{"gene":"CD52","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":1991,"finding":"CD52 (CAMPATH-1/CDw52) is a GPI-anchored glycoprotein with an exceptionally short mature peptide of 12–18 amino acid residues and a single N-linked oligosaccharide at Asn3. The antigenic epitope is heat-stable but sensitive to mild alkali, and the protein is anchored by a glycosylphosphatidylinositol (GPI) anchor as demonstrated by phosphatidylinositol-specific phospholipase C treatment.","method":"Protein purification, N-terminal sequencing, PCR-based cDNA cloning, phospholipase C treatment","journal":"European journal of immunology","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct biochemical purification, sequencing, and enzymatic (PLC) functional validation; foundational structural characterization replicated across subsequent studies","pmids":["1711975"],"is_preprint":false},{"year":1993,"finding":"The antigenic epitope of CD52 recognized by CAMPATH-1 antibodies resides in a proteolytic fragment containing the C-terminal tripeptide and the GPI anchor; proximity of the epitope to the cell membrane (not the N-linked sugar or the first nine amino acids) is the key feature making it an efficient target for complement-mediated lysis. Both native and deglycosylated antigen, as well as proteolytic fragments, can be reincorporated into target cells to confer complement sensitivity.","method":"Complement lysis assay, antigen reincorporation into cells, proteolytic fragmentation, deglycosylation","journal":"Molecular immunology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with functional lysis assay and multiple chemical/enzymatic manipulations; replicated in same lab and consistent with structural data","pmids":["8366859"],"is_preprint":false},{"year":1993,"finding":"CD52 (CDw52/HE5) is expressed at high levels in the male reproductive system (epididymis, seminal vesicle, seminal plasma) and is acquired by maturing (but not testicular) spermatozoa during epididymal transit, representing a novel mechanism of cell-surface antigen acquisition. In the presence of human complement, CAMPATH-1 antibodies inhibit sperm motility; seminal plasma blocks antibody binding and protects sperm.","method":"Immunohistochemistry, flow cytometry, sperm motility assay with complement","journal":"Journal of reproductive immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization by immunohistochemistry and functional motility assay, single lab, two orthogonal methods","pmids":["7685389"],"is_preprint":false},{"year":1993,"finding":"The human epididymal gene HE5 encodes the same peptide backbone as the lymphocyte differentiation antigen CDw52 (CD52); both products are transcribed from a single-copy gene, and expression is highly restricted to epithelial cells of the epididymal and deferent duct.","method":"Differential cDNA library screening, sequencing, Northern blot, in situ hybridization, Southern blot","journal":"Molecular reproduction and development","confidence":"High","confidence_rationale":"Tier 1 / Strong — cDNA sequencing establishing gene identity, in situ hybridization confirming cell-type-specific expression; foundational finding replicated in subsequent studies","pmids":["8418821"],"is_preprint":false},{"year":1995,"finding":"Cross-linking of CD52 on normal resting CD4+ and CD8+ T lymphocytes with anti-CD52 antibodies induces proliferation and lymphokine production in the presence of phorbol esters (or directly with one antibody), and augments anti-CD3-mediated responses when co-immobilized; this activation is inhibited by cyclosporin A, implicating calcineurin-dependent signal transduction pathways. Anti-CD52 antibodies did not synergize with anti-CD2 or anti-CD28, and did not inhibit antigen-specific T cell responses.","method":"T cell proliferation assay, lymphokine production assay, cyclosporin A inhibition, co-immobilization of antibodies","journal":"International immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean primary T cell functional assays with pharmacological inhibition; single lab, two orthogonal functional readouts","pmids":["7718516"],"is_preprint":false},{"year":1996,"finding":"CD52 is expressed on the surface of human eosinophils (but not neutrophils) as a GPI-anchored molecule (confirmed by phospholipase C treatment). Cross-linking of CD52 on eosinophils dose-dependently inhibits reactive oxygen species production stimulated by C5a, platelet-activating factor, and GM-CSF, identifying a functional inhibitory role for CD52 on eosinophils.","method":"Flow cytometry, RT-PCR, Northern blot, phospholipase C treatment, reactive oxygen species assay","journal":"Blood","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct biochemical confirmation of GPI anchor by PLC treatment, functional cross-linking assay with multiple stimuli, multiple orthogonal methods in single study","pmids":["8977262"],"is_preprint":false},{"year":1998,"finding":"Cross-linking CD52 on B-cell and Jurkat T-cell lines (but not receptor-mediated stimulation) induces growth inhibition and apoptosis (Fas/FasL-independent pathway in Wien 133 B cells). Cells surviving anti-CD52 treatment down-regulate CD52 and other GPI-anchored molecules (CD59, CD55) but not transmembrane molecules, due to a defect in GPI precursor synthesis; this phenotype is reversible in vitro and in vivo.","method":"Cell growth assay, flow cytometry, apoptosis assay, in vivo mouse xenograft","journal":"Immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional cross-linking, apoptosis assay with Fas pathway exclusion, in vivo xenograft reversal; single lab","pmids":["9824507"],"is_preprint":false},{"year":1999,"finding":"Male genital tract CD52 differs structurally from lymphocyte CD52: the sperm/seminal plasma form carries mostly 2-inositol palmitoylated, alkylacylglycerol GPI anchors (rendering it resistant to phospholipase C) and highly charged, complex-type N-glycans with lactosamine repeats and peripheral fucose, distinct from the lymphocyte form.","method":"Protein purification from seminal plasma, Western blot, structural mass spectrometry of glycans and GPI anchor","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — detailed structural mass spectrometry of purified protein; rigorous biochemical analysis establishing tissue-specific post-translational modification","pmids":["10514467"],"is_preprint":false},{"year":2000,"finding":"CD52-mediated signal transduction in T cells requires the co-expression of both the T cell receptor (TCR) and the CD45 tyrosine phosphatase at the cell surface; cross-linking of CD52 triggers TCR-dependent protein tyrosine phosphorylation (involving p56lck and p59fyn regulated by CD45) without activating phospholipase Cγ1 or calcium signals. FRET analysis demonstrated CD52 homo-association at the cell surface independent of TCR/CD45, and CD52-TCR association in CD45+TCR+ cells.","method":"Protein tyrosine phosphorylation assay in primary T cells and Jurkat subclones transfected with CD52, FRET, pharmacological inhibition","journal":"International immunology","confidence":"High","confidence_rationale":"Tier 1 / Strong — transfected cell lines with defined genetic backgrounds, FRET for protein associations, multiple orthogonal readouts (phosphorylation, FRET, Ca2+ flux), single lab","pmids":["10744652"],"is_preprint":false},{"year":2003,"finding":"In a murine ATL model, the major tumor-killing mechanism of alemtuzumab (anti-CD52) in vivo requires Fcγ receptor-containing receptors (e.g., FcγRIII) on polymorphonuclear leukocytes and macrophages, as demonstrated using FcRγ-knockout mice; FcRγ-mediated ADCC and/or cross-linking-induced apoptosis are the primary mechanisms.","method":"In vivo NOD/SCID mouse xenograft, FcRγ-knockout mice, survival analysis","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockout mouse model with defined phenotypic readout (survival); single lab, single model","pmids":["14559836"],"is_preprint":false},{"year":2009,"finding":"In a human CD52 transgenic mouse model, alemtuzumab-mediated lymphocyte depletion and cytokine induction are largely independent of complement (cobra venom factor treatment had no impact) but are mediated primarily by neutrophils and NK cells, as demonstrated by antibody depletion of Gr-1+ or asialo-GM-1+ populations.","method":"Transgenic mouse model, cobra venom factor complement depletion, antibody depletion of neutrophil (Gr-1) and NK cell (asialo-GM-1) populations, flow cytometry","journal":"Immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple genetic/immunological perturbations in defined transgenic model with replicated functional readouts; rigorous controls for both complement and cellular effectors","pmids":["19740383"],"is_preprint":false},{"year":2013,"finding":"Soluble CD52, released from the surface of activated T cells by phospholipase C, binds to the inhibitory receptor Siglec-10 on T cells and suppresses T cell activation by impairing phosphorylation of the TCR-associated kinases Lck and Zap70. Transfer of lymphocyte populations depleted of CD52hi cells into NOD mice substantially accelerated onset of diabetes.","method":"Phospholipase C release assay, Siglec-10 binding assay, kinase phosphorylation assay (Lck, Zap70), NOD mouse adoptive transfer","journal":"Nature immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct biochemical binding, kinase phosphorylation assays, and in vivo adoptive transfer model; multiple orthogonal methods; published in Nature Immunology","pmids":["23685786"],"is_preprint":false},{"year":2018,"finding":"CD52-mediated suppression of T cells requires the DAMP protein HMGB1 as an intermediary: soluble CD52 binds specifically to the proinflammatory Box B domain of HMGB1 via its N-linked glycan (α-2,3 sialic acid linkage with galactose), which then promotes binding to Siglec-10. This triggers tyrosine phosphorylation of Siglec-10 and recruitment of SHP1 phosphatase to the intracellular ITIM motif of Siglec-10, which associates with the TCR; T cell suppression was blocked by anti-HMGB1 antibody or Box A domain of HMGB1.","method":"CD52-Fc binding assays, HMGB1 domain-specific blocking, co-immunoprecipitation (CD52/HMGB1/Siglec-10/SHP1/TCR complex), Siglec-10 phosphorylation assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution of complex, domain-specific mapping, co-IP of multi-protein complex, phosphorylation assay, blocking experiments; multiple orthogonal methods in single rigorous study","pmids":["29997173"],"is_preprint":false},{"year":2017,"finding":"Soluble CD52 inhibits Toll-like receptor and TNF receptor signaling to limit NF-κB activation and reduce inflammatory cytokine production in macrophages, monocytes, and dendritic cells. At higher concentrations, soluble CD52 depletes MCL-1, activating BH3-only proteins BAX and BAK to cause intrinsic apoptotic cell death. In vivo, CD52 administration suppresses LPS-induced cytokine secretion, while genetic deletion of CD52 exacerbates LPS responses.","method":"NF-κB reporter assays, cytokine measurement, MCL-1/BAX/BAK protein assays, CD52 knockout mice, LPS endotoxic shock model","journal":"Cell death and differentiation","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockout with defined in vivo phenotype, multiple molecular pathway readouts (NF-κB, MCL-1, BAX/BAK), multiple cell types and orthogonal methods","pmids":["29244050"],"is_preprint":false},{"year":2019,"finding":"CD52 bioactivity (T cell suppression) requires tetra-antennary α-2,3 sialylated N-glycans: removal of α-2,3 sialylation abolishes bioactivity, which is restored by re-sialylation with α-2,3 sialyltransferases. O-glycan core type-2 di-sialylated structures at Ser12 are also enriched in bioactive CD52 fractions.","method":"Glycomic analysis (porous graphitized carbon-ESI-MS/MS), glycopeptide analysis (C8-LC-ESI-MS), enzymatic desialylation and re-sialylation, anion exchange fractionation, T cell suppression bioassay","journal":"Frontiers in immunology","confidence":"High","confidence_rationale":"Tier 1 / Strong — enzymatic gain-of-function and loss-of-function (desialylation/re-sialylation) combined with structural mass spectrometry and functional bioassay; multiple orthogonal methods","pmids":["31507595"],"is_preprint":false},{"year":2021,"finding":"On B cells, surface CD52 functions as a homeostatic inhibitory molecule: CD52-deficient JeKo-1 cells are hyperresponsive to BCR signaling. Antigen-specific BCR activation triggers CD52 cleavage in a phospholipase C-dependent manner, reducing surface CD52. Soluble CD52-Fc inhibits BCR signaling partially through Siglec-10, reduces surface immunoglobulin and CXCR5, and promotes expansion of IgD+IgMlo anergic B cells.","method":"CD52-knockout cell line (JeKo-1), BCR signaling assay, phospholipase C inhibition, recombinant CD52-Fc treatment, Siglec-10 blocking, flow cytometry","journal":"Frontiers in immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function cell line, pharmacological inhibition of PLC, recombinant protein functional assay; single lab, multiple readouts","pmids":["33658999"],"is_preprint":false},{"year":2021,"finding":"In monocytes, CD52 expression negatively regulates cell adhesion: overexpression of CD52 decreases CD18 levels and monocyte adhesion, while knockdown of CD52 increases monocyte adhesion. CD52 expression is upregulated by IL-4/IL-13 via the STAT6 pathway and downregulated by LPS and type I/II IFNs via JAK1 and HDAC IIa.","method":"CD52 overexpression and siRNA knockdown in monocytes, adhesion assay, STAT6/JAK1/HDAC IIa pathway inhibitors, cytokine stimulation","journal":"Arthritis & rheumatology (Hoboken, N.J.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — bidirectional gain/loss-of-function with defined pathway inhibitors and phenotypic readout; single lab","pmids":["33760395"],"is_preprint":false},{"year":1998,"finding":"Crystal structures of the rat CAMPATH-1G and humanized CAMPATH-1H Fab fragments were solved at 2.6 Å and 3.25 Å resolution, revealing that the antibody-combining site is dominated by LysH52b and LysH53 protrusions from loop H2, and that framework residues H71 and H24 are major determinants of structural differences between rat and humanized antibody loops H1 and H2.","method":"X-ray crystallography","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structures of both rat and humanized antibody Fab fragments with detailed structural comparison","pmids":["9811544"],"is_preprint":false},{"year":2019,"finding":"Co-crystal structure of an anti-CD52 antibody Fab with a CD52 peptide mimetic solved at 2.2 Å (PDB 6OBD) revealed that Asn33 of the antibody light chain CDR1 directly contacts the CD52 phosphate group via a hydrogen bond; mutation of Asn33 to Asp (deamidation mimic) reduces antigen binding affinity ~400-fold.","method":"X-ray crystallography, site-directed mutagenesis, Biacore binding affinity measurement, CDC assay","journal":"mAbs","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure combined with systematic mutagenesis and quantitative binding assays; multiple orthogonal methods in single study","pmids":["31199181"],"is_preprint":false},{"year":2008,"finding":"CD52-null mice generated by gene disruption are fertile and show normal sperm viability, motility, morphology, and fertilizing ability both in vivo and in vitro, demonstrating that CD52 is not required for fertilization in the mouse despite being a major sperm maturation-associated antigen.","method":"Gene knockout (Cd52 null mice), in vitro fertilization, sperm parameter analysis, litter size measurement","journal":"Genes to cells : devoted to molecular & cellular mechanisms","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean knockout mouse with comprehensive in vivo and in vitro fertilization phenotyping; negative finding definitively established","pmids":["18782223"],"is_preprint":false},{"year":1997,"finding":"The GPI anchor of male genital tract CD52 contains 2-inositol palmitoylation that renders the molecule insensitive to phospholipase C cleavage, in contrast to lymphocyte CD52; sperm CD52 is acquired from epididymal secretions and associates with large molecular carriers in seminal plasma during transfer onto spermatozoa.","method":"Phospholipase C treatment, flow cytometry, Western blot, size filtration of seminal plasma","journal":"Molecular reproduction and development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — PLC treatment establishing anchor modification, filtration experiments, multiple cell/tissue sources; single lab","pmids":["9291477"],"is_preprint":false},{"year":2024,"finding":"CLL cell-derived CD52 (and CD24) expressed on the CLL cell surface suppresses CAR T cell function via Siglec-10 signaling; blocking CD24 and/or CD52 markedly reduced CAR T cell dysfunction upon coculture with resting CLL cells. CD40 stimulation of CLL cells downregulated CD52 expression via SRC kinase signaling (reversed by dasatinib), restoring T cell function.","method":"Co-culture assays (CLL + CAR T cells), antibody blocking of CD52/CD24, dasatinib pharmacological inhibition, transcriptome profiling, flow cytometry","journal":"Blood advances","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct antibody blocking establishing functional role, pharmacological pathway dissection; single lab, multiple readouts","pmids":["39042920"],"is_preprint":false},{"year":2005,"finding":"Different glycoforms of CD52 associate differently with lipid microdomains: lymphocyte CD52 (both CAMPATH epitope and O-glycan-bearing glycoforms) resides in cholesterol-rich lipid rafts, whereas in capacitated sperm the O-glycoform associates with GM3-rich microdomains distinct from classical rafts. Heterologous CD52 insertion experiments confirmed the importance of the association between GM3 and O-glycans for specialized microdomain formation.","method":"Brij 98 solubilization, sucrose density gradient centrifugation, heterologous CD52 insertion (prostasomes into rat sperm), Western blot","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — biochemical fractionation with heterologous insertion experiment; single lab, two orthogonal approaches","pmids":["16266689"],"is_preprint":false},{"year":2014,"finding":"Activated RAS signaling profoundly promotes surface expression of CD52 on mast cells, as demonstrated in the MCPV-1 cell line generated by lentiviral immortalization. CD52 is expressed at high levels on neoplastic mast cells in advanced systemic mastocytosis but not on normal or indolent SM mast cells.","method":"Lentiviral immortalization, functional studies in MCPV-1 cell line, flow cytometry, NSG mouse xenograft","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional cell line model with RAS pathway manipulation; single lab, mechanistic claim about RAS regulation of CD52 expression","pmids":["24760752"],"is_preprint":false},{"year":1997,"finding":"CD52 expression on sperm is regulated by epididymal maturation: the percentage of sperm expressing CD52 increases progressively from 0.5% in spermatocoeles to 85.7% in the cauda epididymidis, tracking acquisition of motility. CD52 levels on sperm positively correlate with percentage of motile cells, suggesting involvement in sperm maturation.","method":"Flow cytometry with CAMPATH-1G, quantitative immunostaining of sperm from different epididymal regions","journal":"Molecular human reproduction","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct quantitative flow cytometric localization across epididymal regions correlating with functional parameter; single lab","pmids":["9464849"],"is_preprint":false},{"year":1996,"finding":"CD52 mRNA levels in epididymal cells are regulated post-transcriptionally by temperature: exposure to 37°C (vs. 33°C) rapidly and irreversibly suppresses CD52/CE5 mRNA in a specific manner without affecting other epididymal mRNAs, as shown in dog epididymal cell culture; cycloheximide and DRB experiments suggest mRNA half-life regulation.","method":"Epididymal cell culture, Northern blot, temperature shift experiments, cycloheximide and DRB treatment","journal":"Endocrinology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct experimental manipulation (temperature, inhibitors) in cell culture with specific mRNA quantification; single lab","pmids":["8828507"],"is_preprint":false},{"year":2002,"finding":"Peripheral blood myeloid dendritic cells (lineage−HLA-DR+CD11c+) express CD52 and are depleted by alemtuzumab treatment in patients, while tissue-resident Langerhans cells and dermal-interstitial DCs do not express CD52 under steady-state or inflammatory conditions. Depletion of CD52+ cells from normal PB strongly inhibits allogeneic MLR and primary autologous responses to KLH. CD52 expression is lost during monocyte-derived DC maturation with LPS.","method":"Four-color flow cytometry, immunohistochemistry of skin and gut, allogeneic MLR, KLH primary response assay, patient sample analysis before/after alemtuzumab","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization by flow cytometry and IHC with functional MLR assay; replicated across two complementary papers (PMID 12176892, 12393688)","pmids":["12176892","12393688"],"is_preprint":false}],"current_model":"CD52 is a GPI-anchored glycoprotein of only 12 mature amino acids bearing a single complex N-linked glycan; when expressed on the lymphocyte surface it can transduce costimulatory signals via TCR/CD45-dependent tyrosine kinase pathways upon cross-linking, while soluble CD52 released by phospholipase C-mediated shedding acts as an immunosuppressant by binding the proinflammatory HMGB1 Box B domain, facilitating engagement of the inhibitory Siglec-10 receptor, and recruiting SHP1 to impair Lck/Zap70 phosphorylation and NF-κB signaling; the immunosuppressive activity requires specific tetra-antennary α-2,3-sialylated N-glycans, the protein is subject to tissue-specific GPI anchor and glycan modifications (especially in the male reproductive tract), and its expression is transcriptionally regulated by androgens, temperature, and cytokine signaling (IL-4/IL-13 via STAT6; IFN/LPS via JAK1 and HDAC IIa)."},"narrative":{"mechanistic_narrative":"CD52 (CAMPATH-1/CDw52) is a GPI-anchored cell-surface glycoprotein with an exceptionally short mature peptide of only 12-18 amino acids carrying a single N-linked oligosaccharide at Asn3, expressed on lymphocytes and other immune cells as well as in the male reproductive tract [PMID:1711975, PMID:8418821]. Its proximity to the membrane and GPI anchor make it an efficient target for complement-mediated lysis, the basis for the therapeutic antibody alemtuzumab whose in vivo depleting activity is mediated principally by FcγR-bearing neutrophils, NK cells, and macrophages rather than complement [PMID:8366859, PMID:14559836, PMID:19740383]. On the lymphocyte surface CD52 self-associates and physically couples to the TCR, transducing tyrosine-kinase signals through p56lck/p59fyn in a manner dependent on co-expression of the TCR and the CD45 phosphatase [PMID:10744652]. CD52 functions as a homeostatic inhibitory molecule: a soluble form released from activated T and B cells by phospholipase C-mediated shedding suppresses lymphocyte activation, requiring tetra-antennary α-2,3-sialylated N-glycans for bioactivity [PMID:23685786, PMID:31507595, PMID:33658999]. Mechanistically, soluble CD52 binds the proinflammatory Box B domain of the DAMP protein HMGB1 via its sialylated glycan, which promotes engagement of the inhibitory receptor Siglec-10, triggering Siglec-10 phosphorylation and recruitment of the SHP1 phosphatase to its ITIM, thereby impairing Lck/Zap70 phosphorylation [PMID:29997173]. CD52 broadly dampens innate inflammatory signaling, inhibiting TLR/TNFR-driven NF-κB activation and, at high concentrations, depleting MCL-1 to activate BAX/BAK-dependent intrinsic apoptosis, with CD52-knockout mice showing exacerbated LPS responses [PMID:29244050]. CD52 also exerts inhibitory effects on eosinophil reactive oxygen species production, monocyte adhesion, and B-cell receptor signaling, and its expression is regulated by cytokines (IL-4/IL-13 via STAT6; IFN/LPS via JAK1/HDAC IIa) and RAS signaling [PMID:8977262, PMID:33760395, PMID:24760752]. In the male genital tract CD52 is acquired by maturing spermatozoa during epididymal transit and carries distinct, PLC-resistant palmitoylated GPI anchors and complex N-glycans, but it is dispensable for fertility in the mouse [PMID:7685389, PMID:10514467, PMID:18782223].","teleology":[{"year":1991,"claim":"Establishing CD52 as a GPI-anchored glycoprotein with a uniquely minimal peptide backbone defined the molecular nature of the CAMPATH-1 antigen and explained its accessibility at the cell surface.","evidence":"Protein purification, N-terminal sequencing, cDNA cloning, and PLC treatment","pmids":["1711975"],"confidence":"High","gaps":["No endogenous physiological ligand identified at this stage","Function of the short peptide unknown"]},{"year":1993,"claim":"Localizing the antibody epitope to the C-terminal GPI-proximal region explained why CD52 is an efficient target for complement lysis, and reconstitution showed the antigen can be transferred onto cells to confer sensitivity.","evidence":"Complement lysis assay, antigen reincorporation, proteolytic and deglycosylation manipulations","pmids":["8366859"],"confidence":"High","gaps":["Did not address signaling or non-antibody-dependent function","Effector mechanism in vivo not tested"]},{"year":1993,"claim":"Identification of the epididymal HE5 gene as encoding the same backbone as lymphocyte CDw52 established that a single-copy gene produces CD52 in both immune and male reproductive tissues, while sperm functional assays raised a reproductive role.","evidence":"Differential cDNA screening, in situ hybridization, Southern blot, sperm motility assay with complement","pmids":["8418821","7685389"],"confidence":"High","gaps":["Causal requirement of CD52 in sperm function not established","Tissue-specific modifications not yet characterized"]},{"year":1995,"claim":"Demonstrating that anti-CD52 cross-linking drives T-cell proliferation and lymphokine production in a cyclosporin-sensitive manner first implicated CD52 as a costimulatory signaling molecule rather than an inert antigen.","evidence":"Primary T-cell proliferation and lymphokine assays with cyclosporin A inhibition and antibody co-immobilization","pmids":["7718516"],"confidence":"Medium","gaps":["Molecular signaling intermediates not defined","Reliance on antibody cross-linking rather than a natural ligand"]},{"year":1996,"claim":"Extending CD52 expression and inhibitory function to eosinophils showed it can dampen innate effector responses, broadening its role beyond lymphocytes.","evidence":"Flow cytometry, PLC treatment, and reactive oxygen species assays with multiple stimuli","pmids":["8977262"],"confidence":"High","gaps":["Signaling pathway for ROS inhibition not mapped","Endogenous trigger unknown"]},{"year":1997,"claim":"Tracking CD52 acquisition across epididymal regions and identifying PLC-resistant palmitoylated GPI anchors revealed tissue-specific post-translational tailoring of the molecule during sperm maturation.","evidence":"Quantitative flow cytometry across epididymal regions; PLC treatment, filtration of seminal plasma","pmids":["9464849","9291477"],"confidence":"Medium","gaps":["Correlation with motility not shown to be causal","Carrier identity in seminal plasma undefined"]},{"year":1998,"claim":"Showing that anti-CD52 cross-linking induces Fas-independent apoptosis in lymphoid lines, accompanied by loss of GPI biosynthesis, illuminated antibody-induced cell death and a route to antigen-loss escape.","evidence":"Cell growth and apoptosis assays, flow cytometry, in vivo xenograft reversal","pmids":["9824507"],"confidence":"Medium","gaps":["Mechanism linking cross-linking to GPI synthesis defect unclear","Relevance to physiological signaling uncertain"]},{"year":1998,"claim":"Crystal structures of the rat and humanized CAMPATH Fab fragments defined the antibody-combining site and the framework determinants of humanization, supporting therapeutic antibody engineering.","evidence":"X-ray crystallography of CAMPATH-1G and CAMPATH-1H Fab fragments","pmids":["9811544"],"confidence":"High","gaps":["Structure of the antigen-bound complex not resolved here","No insight into CD52 native function"]},{"year":2000,"claim":"Demonstrating that CD52 signaling requires both TCR and CD45 and triggers lck/fyn-dependent phosphorylation, with FRET-confirmed CD52 homo-association and CD52-TCR coupling, defined the membrane signaling architecture of surface CD52.","evidence":"Tyrosine phosphorylation assays in transfected Jurkat subclones, FRET, pharmacological inhibition","pmids":["10744652"],"confidence":"High","gaps":["Downstream transcriptional consequences not mapped","Molecular basis of CD52-TCR association undefined"]},{"year":2003,"claim":"FcRγ-knockout experiments established that alemtuzumab tumor killing in vivo depends on FcγR-bearing effector cells, redirecting the understanding of its mechanism away from pure complement lysis.","evidence":"NOD/SCID xenograft and FcRγ-knockout mouse survival analysis","pmids":["14559836"],"confidence":"Medium","gaps":["Relative contribution of ADCC versus apoptosis not quantified","Single tumor model"]},{"year":2009,"claim":"Using human CD52 transgenic mice, depletion was shown to be complement-independent and mediated by neutrophils and NK cells, refining the in vivo effector requirements of alemtuzumab.","evidence":"Transgenic model, cobra venom factor complement depletion, antibody depletion of Gr-1+ and asialo-GM-1+ cells","pmids":["19740383"],"confidence":"High","gaps":["Human-specific effector contributions may differ","Does not address antigen biology"]},{"year":2013,"claim":"Identifying soluble CD52 released by PLC as a Siglec-10-binding suppressor of Lck/Zap70 phosphorylation, with CD52hi depletion accelerating diabetes, established CD52 as a regulatory immunosuppressive mediator.","evidence":"PLC release assay, Siglec-10 binding, kinase phosphorylation assays, NOD mouse adoptive transfer","pmids":["23685786"],"confidence":"High","gaps":["Direct vs indirect Siglec-10 binding not yet resolved","Glycan dependence not yet defined"]},{"year":2017,"claim":"Demonstrating that soluble CD52 inhibits TLR/TNFR-driven NF-κB activation and triggers MCL-1-depletion/BAX-BAK apoptosis at high doses, with CD52-knockout exacerbating LPS responses, defined a broad innate-immune anti-inflammatory role.","evidence":"NF-κB reporters, cytokine measurement, MCL-1/BAX/BAK assays, CD52 knockout mice, LPS shock model","pmids":["29244050"],"confidence":"High","gaps":["Receptor mediating innate NF-κB inhibition not fully resolved","Concentration thresholds in vivo unclear"]},{"year":2018,"claim":"Resolving HMGB1 as a glycan-dependent intermediary that bridges soluble CD52 to Siglec-10, driving SHP1 recruitment to the Siglec-10 ITIM associated with the TCR, provided the complete mechanistic chain of CD52-mediated suppression.","evidence":"CD52-Fc binding, HMGB1 domain-specific blocking, multi-protein co-IP, Siglec-10 phosphorylation assays","pmids":["29997173"],"confidence":"High","gaps":["Stoichiometry of the CD52/HMGB1/Siglec-10 complex undefined","In vivo requirement of HMGB1 not tested"]},{"year":2019,"claim":"Showing that bioactivity strictly requires tetra-antennary α-2,3-sialylated N-glycans, with loss and enzymatic restoration of function, established the glycan code underlying CD52 immunosuppression.","evidence":"Glycomic mass spectrometry, enzymatic desialylation/re-sialylation, T-cell suppression bioassay","pmids":["31507595"],"confidence":"High","gaps":["Glycosyltransferases producing bioactive glycoform in vivo unidentified","Role of O-glycans at Ser12 not functionally isolated"]},{"year":2021,"claim":"Extending the inhibitory model to B cells and monocytes showed CD52 restrains BCR signaling (partly via Siglec-10) and monocyte adhesion, and identified IL-4/IL-13-STAT6 and IFN/LPS-JAK1/HDAC IIa as regulators of its expression.","evidence":"CD52-knockout JeKo-1 cells, BCR signaling and adhesion assays, recombinant CD52-Fc, pathway inhibitors","pmids":["33658999","33760395"],"confidence":"Medium","gaps":["Whether the same HMGB1/Siglec-10 axis operates in B cells and monocytes not fully established","Adhesion mechanism (CD18 regulation) not molecularly traced"]},{"year":2024,"claim":"Demonstrating that CLL-derived CD52 suppresses CAR T-cell function via Siglec-10, reversible by CD40/SRC-mediated downregulation, extended the inhibitory axis to a tumor immune-evasion mechanism with therapeutic implications.","evidence":"CLL/CAR T co-culture, CD52/CD24 antibody blocking, dasatinib inhibition, transcriptome profiling","pmids":["39042920"],"confidence":"Medium","gaps":["Relative contribution of CD52 versus CD24 not isolated","Single-lab co-culture system"]},{"year":null,"claim":"The endogenous receptor(s) and signaling mechanism mediating surface CD52 costimulation, the physiological trigger and in vivo relevance of the HMGB1/Siglec-10 suppressive axis across cell types, and the in vivo enzymes generating bioactive glycoforms remain to be integrated into a single model.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structure of native CD52 bound to HMGB1 or Siglec-10","Reconciliation of costimulatory surface signaling with inhibitory soluble signaling unresolved","Physiological function of reproductive-tract CD52 unknown given fertility of knockout mice"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[8,11,12]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[11,12,13,15]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,1]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,5,8]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[11,7,12]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[8,11,12,13]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[8,12,13]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[6,13]}],"complexes":[],"partners":["SIGLEC10","HMGB1","PTPN6","TCR","CD45","LCK"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P31358","full_name":"CAMPATH-1 antigen","aliases":["CDw52","Cambridge pathology 1 antigen","Epididymal secretory protein E5","Human epididymis-specific protein 5","He5"],"length_aa":61,"mass_kda":6.6,"function":"May play a role in carrying and orienting carbohydrate, as well as having a more specific role","subcellular_location":"Cell membrane","url":"https://www.uniprot.org/uniprotkb/P31358/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CD52","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1090,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CD52","total_profiled":1310},"omim":[{"mim_id":"114280","title":"CAMPATH-1 ANTIGEN; CD52","url":"https://www.omim.org/entry/114280"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"epididymis","ntpm":34113.9}],"url":"https://www.proteinatlas.org/search/CD52"},"hgnc":{"alias_symbol":["HE5","EDDM5"],"prev_symbol":["CDW52"]},"alphafold":{"accession":"P31358","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P31358","model_url":"https://alphafold.ebi.ac.uk/files/AF-P31358-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P31358-F1-predicted_aligned_error_v6.png","plddt_mean":67.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CD52","jax_strain_url":"https://www.jax.org/strain/search?query=CD52"},"sequence":{"accession":"P31358","fasta_url":"https://rest.uniprot.org/uniprotkb/P31358.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P31358/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P31358"}},"corpus_meta":[{"pmid":"9193354","id":"PMC_9193354","title":"Phase II multicenter study of human CD52 antibody in previously treated chronic lymphocytic leukemia. European Study Group of CAMPATH-1H Treatment in Chronic Lymphocytic Leukemia.","date":"1997","source":"Journal of clinical oncology : official journal of the American Society of Clinical Oncology","url":"https://pubmed.ncbi.nlm.nih.gov/9193354","citation_count":416,"is_preprint":false},{"pmid":"12865797","id":"PMC_12865797","title":"Results from a human renal allograft tolerance trial evaluating the humanized CD52-specific monoclonal antibody alemtuzumab (CAMPATH-1H).","date":"2003","source":"Transplantation","url":"https://pubmed.ncbi.nlm.nih.gov/12865797","citation_count":329,"is_preprint":false},{"pmid":"12543862","id":"PMC_12543862","title":"Phase 2 study of alemtuzumab (anti-CD52 monoclonal antibody) in patients with advanced mycosis fungoides/Sezary syndrome.","date":"2003","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/12543862","citation_count":279,"is_preprint":false},{"pmid":"19740383","id":"PMC_19740383","title":"Investigation of the mechanism of action of alemtuzumab in a human CD52 transgenic mouse model.","date":"2009","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/19740383","citation_count":265,"is_preprint":false},{"pmid":"15070664","id":"PMC_15070664","title":"A pilot study of alemtuzumab (anti-CD52 monoclonal antibody) therapy for patients with relapsed or chemotherapy-refractory peripheral T-cell lymphomas.","date":"2003","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/15070664","citation_count":232,"is_preprint":false},{"pmid":"9593475","id":"PMC_9593475","title":"Levels of expression of CD52 in normal and leukemic B and T cells: correlation with in vivo therapeutic responses to Campath-1H.","date":"1998","source":"Leukemia research","url":"https://pubmed.ncbi.nlm.nih.gov/9593475","citation_count":219,"is_preprint":false},{"pmid":"23685786","id":"PMC_23685786","title":"T cell regulation mediated by interaction of soluble CD52 with the inhibitory receptor Siglec-10.","date":"2013","source":"Nature immunology","url":"https://pubmed.ncbi.nlm.nih.gov/23685786","citation_count":165,"is_preprint":false},{"pmid":"9215839","id":"PMC_9215839","title":"Treatment of T-cell prolymphocytic leukemia with human CD52 antibody.","date":"1997","source":"Journal of clinical oncology : official journal of the American Society of Clinical Oncology","url":"https://pubmed.ncbi.nlm.nih.gov/9215839","citation_count":161,"is_preprint":false},{"pmid":"1711975","id":"PMC_1711975","title":"Characterization of the CAMPATH-1 (CDw52) antigen: biochemical analysis and cDNA cloning reveal an unusually small peptide backbone.","date":"1991","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/1711975","citation_count":154,"is_preprint":false},{"pmid":"24198283","id":"PMC_24198283","title":"Differential reconstitution of T cell subsets following immunodepleting treatment with alemtuzumab (anti-CD52 monoclonal antibody) in patients with relapsing-remitting multiple sclerosis.","date":"2013","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/24198283","citation_count":138,"is_preprint":false},{"pmid":"10918407","id":"PMC_10918407","title":"CD52 antibodies for prevention of graft-versus-host disease and graft rejection following transplantation of allogeneic peripheral blood stem cells.","date":"2000","source":"Bone marrow transplantation","url":"https://pubmed.ncbi.nlm.nih.gov/10918407","citation_count":136,"is_preprint":false},{"pmid":"17145843","id":"PMC_17145843","title":"Heterogeneous CD52 expression among hematologic neoplasms: implications for the use of alemtuzumab (CAMPATH-1H).","date":"2006","source":"Clinical cancer research : an official journal of the American Association for Cancer Research","url":"https://pubmed.ncbi.nlm.nih.gov/17145843","citation_count":116,"is_preprint":false},{"pmid":"12393688","id":"PMC_12393688","title":"Differential CD52 expression by distinct myeloid dendritic cell subsets: implications for alemtuzumab activity at the level of antigen presentation in allogeneic graft-host interactions in transplantation.","date":"2002","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/12393688","citation_count":114,"is_preprint":false},{"pmid":"9824507","id":"PMC_9824507","title":"Cross-linking of the CAMPATH-1 antigen (CD52) mediates growth inhibition in human B- and T-lymphoma cell lines, and subsequent emergence of CD52-deficient cells.","date":"1998","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/9824507","citation_count":112,"is_preprint":false},{"pmid":"12176892","id":"PMC_12176892","title":"Peripheral blood but not tissue dendritic cells express CD52 and are depleted by treatment with alemtuzumab.","date":"2002","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/12176892","citation_count":109,"is_preprint":false},{"pmid":"7685389","id":"PMC_7685389","title":"The glycosylphosphatidylinositol-anchored lymphocyte antigen CDw52 is associated with the epididymal maturation of human spermatozoa.","date":"1993","source":"Journal of reproductive immunology","url":"https://pubmed.ncbi.nlm.nih.gov/7685389","citation_count":98,"is_preprint":false},{"pmid":"8366859","id":"PMC_8366859","title":"Efficient complement-mediated lysis of cells containing the CAMPATH-1 (CDw52) antigen.","date":"1993","source":"Molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/8366859","citation_count":95,"is_preprint":false},{"pmid":"28283679","id":"PMC_28283679","title":"The immunological function of CD52 and its targeting in organ transplantation.","date":"2017","source":"Inflammation research : official journal of the European Histamine Research Society ... [et al.]","url":"https://pubmed.ncbi.nlm.nih.gov/28283679","citation_count":92,"is_preprint":false},{"pmid":"10514467","id":"PMC_10514467","title":"Male-specific modification of human CD52.","date":"1999","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10514467","citation_count":91,"is_preprint":false},{"pmid":"14559836","id":"PMC_14559836","title":"Effective therapy for a murine model of adult T-cell leukemia with the humanized anti-CD52 monoclonal antibody, Campath-1H.","date":"2003","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/14559836","citation_count":84,"is_preprint":false},{"pmid":"8418821","id":"PMC_8418821","title":"A major mRNA of the human epididymal principal cells, HE5, encodes the leucocyte differentiation CDw52 antigen peptide backbone.","date":"1993","source":"Molecular reproduction and development","url":"https://pubmed.ncbi.nlm.nih.gov/8418821","citation_count":82,"is_preprint":false},{"pmid":"8977262","id":"PMC_8977262","title":"Surface and mRNA expression of the CD52 antigen by human eosinophils but not by neutrophils.","date":"1996","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/8977262","citation_count":80,"is_preprint":false},{"pmid":"7632956","id":"PMC_7632956","title":"Emergence of CD52-, phosphatidylinositolglycan-anchor-deficient T lymphocytes after in vivo application of Campath-1H for refractory B-cell non-Hodgkin lymphoma.","date":"1995","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/7632956","citation_count":80,"is_preprint":false},{"pmid":"7718516","id":"PMC_7718516","title":"Cross-linking of the CAMPATH-1 antigen (CD52) triggers activation of normal human T lymphocytes.","date":"1995","source":"International immunology","url":"https://pubmed.ncbi.nlm.nih.gov/7718516","citation_count":79,"is_preprint":false},{"pmid":"16688777","id":"PMC_16688777","title":"Activity of alemtuzumab in patients with CD52-positive acute leukemia.","date":"2006","source":"Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/16688777","citation_count":72,"is_preprint":false},{"pmid":"29997173","id":"PMC_29997173","title":"CD52 glycan binds the proinflammatory B box of HMGB1 to engage the Siglec-10 receptor and suppress human T cell function.","date":"2018","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/29997173","citation_count":70,"is_preprint":false},{"pmid":"19236377","id":"PMC_19236377","title":"Variable CD52 expression in mature T cell and NK cell malignancies: implications for alemtuzumab therapy.","date":"2009","source":"British journal of haematology","url":"https://pubmed.ncbi.nlm.nih.gov/19236377","citation_count":67,"is_preprint":false},{"pmid":"8027367","id":"PMC_8027367","title":"Immunohistochemical analysis of CDw52 antigen expression in non-Hodgkin's lymphomas.","date":"1994","source":"Journal of clinical pathology","url":"https://pubmed.ncbi.nlm.nih.gov/8027367","citation_count":66,"is_preprint":false},{"pmid":"30144037","id":"PMC_30144037","title":"Clinical pharmacology of alemtuzumab, an anti-CD52 immunomodulator, in multiple sclerosis.","date":"2018","source":"Clinical and experimental immunology","url":"https://pubmed.ncbi.nlm.nih.gov/30144037","citation_count":64,"is_preprint":false},{"pmid":"9291477","id":"PMC_9291477","title":"Interaction of the human epididymal protein CD52 (HE5) with epididymal spermatozoa from men and cynomolgus monkeys.","date":"1997","source":"Molecular reproduction and development","url":"https://pubmed.ncbi.nlm.nih.gov/9291477","citation_count":61,"is_preprint":false},{"pmid":"20348971","id":"PMC_20348971","title":"Therapy of steroid-refractory acute GVHD with CD52 antibody alemtuzumab is effective.","date":"2010","source":"Bone marrow transplantation","url":"https://pubmed.ncbi.nlm.nih.gov/20348971","citation_count":59,"is_preprint":false},{"pmid":"11257744","id":"PMC_11257744","title":"CD52 antigen--a review.","date":"2001","source":"Medical science monitor : international medical journal of experimental and clinical research","url":"https://pubmed.ncbi.nlm.nih.gov/11257744","citation_count":56,"is_preprint":false},{"pmid":"29244050","id":"PMC_29244050","title":"CD52 inhibits Toll-like receptor activation of NF-κB and triggers apoptosis to suppress inflammation.","date":"2017","source":"Cell death and differentiation","url":"https://pubmed.ncbi.nlm.nih.gov/29244050","citation_count":55,"is_preprint":false},{"pmid":"9238651","id":"PMC_9238651","title":"CD52 is the 'major maturation-associated' sperm membrane antigen.","date":"1996","source":"Molecular human reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/9238651","citation_count":55,"is_preprint":false},{"pmid":"11778765","id":"PMC_11778765","title":"Campath-1H (anti-CD52) monoclonal antibody therapy in lymphoproliferative disorders.","date":"2001","source":"Medical oncology (Northwood, London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/11778765","citation_count":52,"is_preprint":false},{"pmid":"11114591","id":"PMC_11114591","title":"New insights into the origin, structure and role of CD52: a major component of the mammalian sperm glycocalyx.","date":"2001","source":"Cells, tissues, organs","url":"https://pubmed.ncbi.nlm.nih.gov/11114591","citation_count":52,"is_preprint":false},{"pmid":"19638623","id":"PMC_19638623","title":"Neutrophils express CD52 and exhibit complement-mediated lysis in the presence of alemtuzumab.","date":"2009","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/19638623","citation_count":49,"is_preprint":false},{"pmid":"21394097","id":"PMC_21394097","title":"CD52 as a molecular target for immunotherapy to treat acute myeloid leukemia with high EVI1 expression.","date":"2011","source":"Leukemia","url":"https://pubmed.ncbi.nlm.nih.gov/21394097","citation_count":49,"is_preprint":false},{"pmid":"8828507","id":"PMC_8828507","title":"Body temperature (37 C) specifically down-regulates the messenger ribonucleic acid for the major sperm surface antigen CD52 in epididymal cell culture.","date":"1996","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/8828507","citation_count":47,"is_preprint":false},{"pmid":"17488672","id":"PMC_17488672","title":"Expression of CD52 in peripheral T-cell lymphoma.","date":"2007","source":"Haematologica","url":"https://pubmed.ncbi.nlm.nih.gov/17488672","citation_count":46,"is_preprint":false},{"pmid":"9373346","id":"PMC_9373346","title":"Synthetic peptide mimotope of the CAMPATH-1 (CD52) antigen, a small glycosylphosphatidylinositol-anchored glycoprotein.","date":"1995","source":"Immunotechnology : an international journal of immunological engineering","url":"https://pubmed.ncbi.nlm.nih.gov/9373346","citation_count":44,"is_preprint":false},{"pmid":"12714489","id":"PMC_12714489","title":"Expression of CD52 on plasma cells in plasma cell proliferative disorders.","date":"2003","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/12714489","citation_count":43,"is_preprint":false},{"pmid":"27925187","id":"PMC_27925187","title":"Depletion of CD52-positive cells inhibits the development of central nervous system autoimmune disease, but deletes an immune-tolerance promoting CD8 T-cell population. Implications for secondary autoimmunity of alemtuzumab in multiple sclerosis.","date":"2017","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/27925187","citation_count":42,"is_preprint":false},{"pmid":"14632776","id":"PMC_14632776","title":"Circulating CD20 and CD52 in patients with non-Hodgkin's lymphoma or Hodgkin's disease.","date":"2003","source":"British journal of haematology","url":"https://pubmed.ncbi.nlm.nih.gov/14632776","citation_count":41,"is_preprint":false},{"pmid":"18086494","id":"PMC_18086494","title":"Long-term immune reconstitution after anti-CD52-treated or anti-CD34-treated hematopoietic stem cell transplantation for severe T-lymphocyte immunodeficiency.","date":"2007","source":"The Journal of allergy and clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/18086494","citation_count":40,"is_preprint":false},{"pmid":"6316259","id":"PMC_6316259","title":"Integration of viral DNA into the genome of the adenovirus type 2-transformed hamster cell line HE5 without loss or alteration of cellular nucleotides.","date":"1983","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/6316259","citation_count":38,"is_preprint":false},{"pmid":"9148769","id":"PMC_9148769","title":"Antibody selection against CD52 produces a paroxysmal nocturnal haemoglobinuria phenotype in human lymphocytes by a novel mechanism.","date":"1997","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/9148769","citation_count":37,"is_preprint":false},{"pmid":"8671618","id":"PMC_8671618","title":"Emergence of CD52-, glycosylphosphatidylinositol-anchor-deficient lymphocytes in rheumatoid arthritis patients following Campath-1H treatment.","date":"1996","source":"International immunology","url":"https://pubmed.ncbi.nlm.nih.gov/8671618","citation_count":36,"is_preprint":false},{"pmid":"26549384","id":"PMC_26549384","title":"Ex vivo expansion of natural killer cells from human peripheral blood mononuclear cells co-stimulated with anti-CD3 and anti-CD52 monoclonal antibodies.","date":"2015","source":"Cytotherapy","url":"https://pubmed.ncbi.nlm.nih.gov/26549384","citation_count":36,"is_preprint":false},{"pmid":"9020367","id":"PMC_9020367","title":"Clonal CD8+ and CD52- T cells are induced in responding B cell lymphoma patients treated with Campath-1H (anti-CD52).","date":"1997","source":"European journal of haematology","url":"https://pubmed.ncbi.nlm.nih.gov/9020367","citation_count":34,"is_preprint":false},{"pmid":"9464849","id":"PMC_9464849","title":"Human epididymal secreted protein CD52 on ejaculated spermatozoa: correlations with semen characteristics and the effect of its antibody.","date":"1997","source":"Molecular human reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/9464849","citation_count":34,"is_preprint":false},{"pmid":"16796779","id":"PMC_16796779","title":"CD52 is expressed on human mast cells and is a potential therapeutic target in Waldenstrom's Macroglobulinemia and mast cell disorders.","date":"2006","source":"Clinical lymphoma & myeloma","url":"https://pubmed.ncbi.nlm.nih.gov/16796779","citation_count":34,"is_preprint":false},{"pmid":"10744652","id":"PMC_10744652","title":"The CD45 tyrosine phosphatase regulates Campath-1H (CD52)-induced TCR-dependent signal transduction in human T cells.","date":"2000","source":"International immunology","url":"https://pubmed.ncbi.nlm.nih.gov/10744652","citation_count":34,"is_preprint":false},{"pmid":"14635201","id":"PMC_14635201","title":"CD52 expression in hairy cell leukemia.","date":"2003","source":"American journal of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/14635201","citation_count":33,"is_preprint":false},{"pmid":"19794084","id":"PMC_19794084","title":"Therapeutic implications of variable expression of CD52 on clonal cytotoxic T cells in CD8+ large granular lymphocyte leukemia.","date":"2009","source":"Haematologica","url":"https://pubmed.ncbi.nlm.nih.gov/19794084","citation_count":33,"is_preprint":false},{"pmid":"11420384","id":"PMC_11420384","title":"Changes of the major sperm maturation-associated epididymal protein HE5 (CD52) on human ejaculated spermatozoa during incubation.","date":"2001","source":"Molecular human reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/11420384","citation_count":30,"is_preprint":false},{"pmid":"1352921","id":"PMC_1352921","title":"The distribution of the CDW52 molecule on blood cells and characterization of its involvement in T cell activation.","date":"1992","source":"Transplantation","url":"https://pubmed.ncbi.nlm.nih.gov/1352921","citation_count":30,"is_preprint":false},{"pmid":"24760752","id":"PMC_24760752","title":"CD52 is a molecular target in advanced systemic mastocytosis.","date":"2014","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/24760752","citation_count":30,"is_preprint":false},{"pmid":"18067019","id":"PMC_18067019","title":"CD52 over-expression affects rituximab-associated complement-mediated cytotoxicity but not antibody-dependent cellular cytotoxicity: preclinical evidence that targeting CD52 with alemtuzumab may reverse acquired resistance to rituximab in non-Hodgkin lymphoma.","date":"2007","source":"Leukemia & lymphoma","url":"https://pubmed.ncbi.nlm.nih.gov/18067019","citation_count":29,"is_preprint":false},{"pmid":"15390358","id":"PMC_15390358","title":"Anti-CD52 antibody, alemtuzumab, binds to Langerhans cells in Langerhans cell histiocytosis.","date":"2005","source":"Pediatric blood & cancer","url":"https://pubmed.ncbi.nlm.nih.gov/15390358","citation_count":29,"is_preprint":false},{"pmid":"8690449","id":"PMC_8690449","title":"Recognition of CD52 allelic gene products by CAMPATH-1H antibodies.","date":"1996","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/8690449","citation_count":29,"is_preprint":false},{"pmid":"38242120","id":"PMC_38242120","title":"Surface CD52, CD84, and PTGER2 mark mature PMN-MDSCs from cancer patients and G-CSF-treated donors.","date":"2024","source":"Cell reports. Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38242120","citation_count":28,"is_preprint":false},{"pmid":"33658999","id":"PMC_33658999","title":"CD52 Is Elevated on B cells of SLE Patients and Regulates B Cell Function.","date":"2021","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/33658999","citation_count":28,"is_preprint":false},{"pmid":"16019510","id":"PMC_16019510","title":"CD52 expression in T-cell large granular lymphocyte leukemia--implications for treatment with alemtuzumab.","date":"2005","source":"Leukemia & lymphoma","url":"https://pubmed.ncbi.nlm.nih.gov/16019510","citation_count":28,"is_preprint":false},{"pmid":"24799522","id":"PMC_24799522","title":"Identification of campath-1 (CD52) as novel drug target in neoplastic stem cells in 5q-patients with MDS and AML.","date":"2014","source":"Clinical cancer research : an official journal of the American Association for Cancer Research","url":"https://pubmed.ncbi.nlm.nih.gov/24799522","citation_count":27,"is_preprint":false},{"pmid":"9811544","id":"PMC_9811544","title":"Crystal structures of a rat anti-CD52 (CAMPATH-1) therapeutic antibody Fab fragment and its humanized counterpart.","date":"1998","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/9811544","citation_count":27,"is_preprint":false},{"pmid":"25511139","id":"PMC_25511139","title":"Cytogenetic and flow cytometry evaluation of Richter syndrome reveals MYC, CDKN2A, IGH alterations with loss of CD52, CD62L and increase of CD71 antigen expression as the most frequent recurrent abnormalities.","date":"2015","source":"American journal of clinical pathology","url":"https://pubmed.ncbi.nlm.nih.gov/25511139","citation_count":26,"is_preprint":false},{"pmid":"20848033","id":"PMC_20848033","title":"Expeditious chemoenzymatic synthesis of CD52 glycopeptide antigens.","date":"2010","source":"Organic & biomolecular chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20848033","citation_count":26,"is_preprint":false},{"pmid":"18782223","id":"PMC_18782223","title":"Cd52, known as a major maturation-associated sperm membrane antigen secreted from the epididymis, is not required for fertilization in the mouse.","date":"2008","source":"Genes to cells : devoted to molecular & cellular mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/18782223","citation_count":25,"is_preprint":false},{"pmid":"17325855","id":"PMC_17325855","title":"CD52 expression in non-mycotic T- and NK/T-cell lymphomas.","date":"2007","source":"Leukemia & lymphoma","url":"https://pubmed.ncbi.nlm.nih.gov/17325855","citation_count":24,"is_preprint":false},{"pmid":"26372145","id":"PMC_26372145","title":"Characterisation of a Novel Anti-CD52 Antibody with Improved Efficacy and Reduced Immunogenicity.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/26372145","citation_count":24,"is_preprint":false},{"pmid":"15794865","id":"PMC_15794865","title":"CD52 expression in Waldenstrom's macroglobulinemia: implications for alemtuzumab therapy and response assessment.","date":"2005","source":"Clinical lymphoma","url":"https://pubmed.ncbi.nlm.nih.gov/15794865","citation_count":24,"is_preprint":false},{"pmid":"14662784","id":"PMC_14662784","title":"Vasectomy influences expression of HE1 but not HE2 and HE5 genes in human epididymis.","date":"2004","source":"Journal of andrology","url":"https://pubmed.ncbi.nlm.nih.gov/14662784","citation_count":23,"is_preprint":false},{"pmid":"23934027","id":"PMC_23934027","title":"Immune regulation by CD52-expressing CD4 T cells.","date":"2013","source":"Cellular & molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/23934027","citation_count":23,"is_preprint":false},{"pmid":"16325507","id":"PMC_16325507","title":"Giant cell tumors of the bone: molecular profiling and expression analysis of Ephrin A1 receptor, Claudin 7, CD52, FGFR3 and AMFR.","date":"2005","source":"Pathology, research and practice","url":"https://pubmed.ncbi.nlm.nih.gov/16325507","citation_count":23,"is_preprint":false},{"pmid":"16266689","id":"PMC_16266689","title":"Different glycoforms of the human GPI-anchored antigen CD52 associate differently with lipid microdomains in leukocytes and sperm membranes.","date":"2005","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/16266689","citation_count":23,"is_preprint":false},{"pmid":"25087772","id":"PMC_25087772","title":"Anti-mouse CD52 monoclonal antibody ameliorates intestinal epithelial barrier function in interleukin-10 knockout mice with spontaneous chronic colitis.","date":"2015","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/25087772","citation_count":22,"is_preprint":false},{"pmid":"10524207","id":"PMC_10524207","title":"Structure and chromosomal location of mouse and human CD52 genes.","date":"1999","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/10524207","citation_count":21,"is_preprint":false},{"pmid":"19479612","id":"PMC_19479612","title":"CD52 expression in peripheral T-cell lymphomas determined by combined immunophenotyping using tumor cell specific T-cell receptor antibodies.","date":"2009","source":"Leukemia & lymphoma","url":"https://pubmed.ncbi.nlm.nih.gov/19479612","citation_count":21,"is_preprint":false},{"pmid":"18223233","id":"PMC_18223233","title":"A novel Raji-Burkitt's lymphoma model for preclinical and mechanistic evaluation of CD52-targeted immunotherapeutic agents.","date":"2008","source":"Clinical cancer research : an official journal of the American Association for Cancer Research","url":"https://pubmed.ncbi.nlm.nih.gov/18223233","citation_count":21,"is_preprint":false},{"pmid":"16995884","id":"PMC_16995884","title":"Reconstitution of the T-cell repertoire following treatment with alemtuzumab (anti-CD52 monoclonal antibody) in patients with B-cell chronic lymphocytic leukaemia.","date":"2006","source":"British journal of haematology","url":"https://pubmed.ncbi.nlm.nih.gov/16995884","citation_count":21,"is_preprint":false},{"pmid":"33760395","id":"PMC_33760395","title":"Regulation of Monocyte Adhesion and Type I Interferon Signaling by CD52 in Patients With Systemic Sclerosis.","date":"2021","source":"Arthritis & rheumatology (Hoboken, N.J.)","url":"https://pubmed.ncbi.nlm.nih.gov/33760395","citation_count":20,"is_preprint":false},{"pmid":"28087077","id":"PMC_28087077","title":"Alteration of CD39+Foxp3+ CD4 T cell and cytokine levels in EAE/MS following anti-CD52 treatment.","date":"2016","source":"Journal of neuroimmunology","url":"https://pubmed.ncbi.nlm.nih.gov/28087077","citation_count":20,"is_preprint":false},{"pmid":"31199181","id":"PMC_31199181","title":"Engineering an anti-CD52 antibody for enhanced deamidation stability.","date":"2019","source":"mAbs","url":"https://pubmed.ncbi.nlm.nih.gov/31199181","citation_count":19,"is_preprint":false},{"pmid":"15720389","id":"PMC_15720389","title":"Kinetic and binding studies with purified recombinant proteins ferredoxin reductase, ferredoxin and cytochrome P450 comprising the morpholine mono-oxygenase from Mycobacterium sp. strain HE5.","date":"2005","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/15720389","citation_count":18,"is_preprint":false},{"pmid":"10737964","id":"PMC_10737964","title":"CD52 mRNA is modulated by androgens and temperature in epididymal cell cultures.","date":"2000","source":"Molecular reproduction and development","url":"https://pubmed.ncbi.nlm.nih.gov/10737964","citation_count":18,"is_preprint":false},{"pmid":"9364437","id":"PMC_9364437","title":"Regionalized expression of CD52 in rat epididymis is related to mRNA poly(A) tail length.","date":"1997","source":"Molecular reproduction and development","url":"https://pubmed.ncbi.nlm.nih.gov/9364437","citation_count":18,"is_preprint":false},{"pmid":"16728276","id":"PMC_16728276","title":"CD52 antigen expressed by malignant plasma cells can be targeted by alemtuzumab in vivo in NOD/SCID mice.","date":"2006","source":"Experimental hematology","url":"https://pubmed.ncbi.nlm.nih.gov/16728276","citation_count":18,"is_preprint":false},{"pmid":"12042050","id":"PMC_12042050","title":"Impact on T-cell depletion and CD34+ cell recovery using humanised CD52 monoclonal antibody (CAMPATH-1H) in BM and PSBC collections; comparison with CAMPATH-1M and CAMPATH-1G.","date":"2000","source":"Cytotherapy","url":"https://pubmed.ncbi.nlm.nih.gov/12042050","citation_count":18,"is_preprint":false},{"pmid":"11911422","id":"PMC_11911422","title":"Immunophenotype changes and loss of CD52 expression in two patients with relapsed T-cell prolymphocytic leukaemia.","date":"2001","source":"Leukemia & lymphoma","url":"https://pubmed.ncbi.nlm.nih.gov/11911422","citation_count":18,"is_preprint":false},{"pmid":"35475910","id":"PMC_35475910","title":"Interleukin-15 augments NK cell-mediated ADCC of alemtuzumab in patients with CD52+ T-cell malignancies.","date":"2023","source":"Blood advances","url":"https://pubmed.ncbi.nlm.nih.gov/35475910","citation_count":17,"is_preprint":false},{"pmid":"11549020","id":"PMC_11549020","title":"A cytochrome P450 and a ferredoxin isolated from Mycobacterium sp. strain HE5 after growth on morpholine.","date":"2001","source":"Applied microbiology and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/11549020","citation_count":17,"is_preprint":false},{"pmid":"28830605","id":"PMC_28830605","title":"Quantitative flow cytometric evaluation of CD200, CD123, CD43 and CD52 as a tool for the differential diagnosis of mature B-cell neoplasms.","date":"2017","source":"Revista brasileira de hematologia e hemoterapia","url":"https://pubmed.ncbi.nlm.nih.gov/28830605","citation_count":17,"is_preprint":false},{"pmid":"17428002","id":"PMC_17428002","title":"Different levels of CD52 antigen expression evaluated by quantitative fluorescence cytometry are detected on B-lymphocytes, CD 34+ cells and tumor cells of patients with chronic B-cell lymphoproliferative diseases.","date":"2007","source":"Cytometry. Part B, Clinical cytometry","url":"https://pubmed.ncbi.nlm.nih.gov/17428002","citation_count":17,"is_preprint":false},{"pmid":"11986948","id":"PMC_11986948","title":"Phenotypic transformation of CD52(pos) to CD52(neg) leukemic T cells as a mechanism for resistance to CAMPATH-1H.","date":"2002","source":"Leukemia","url":"https://pubmed.ncbi.nlm.nih.gov/11986948","citation_count":17,"is_preprint":false},{"pmid":"12021047","id":"PMC_12021047","title":"Analysis of a human sperm CD52 glycoform in primates: identification of an animal model for immunocontraceptive vaccine development.","date":"2002","source":"Biology of reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/12021047","citation_count":17,"is_preprint":false},{"pmid":"30098594","id":"PMC_30098594","title":"Anti-CD52 antibody treatment depletes B cell aggregates in the central nervous system in a mouse model of multiple sclerosis.","date":"2018","source":"Journal of neuroinflammation","url":"https://pubmed.ncbi.nlm.nih.gov/30098594","citation_count":16,"is_preprint":false},{"pmid":"12492811","id":"PMC_12492811","title":"A male genital tract-specific carbohydrate epitope on human CD52: implications for immunocontraception.","date":"2002","source":"Tissue antigens","url":"https://pubmed.ncbi.nlm.nih.gov/12492811","citation_count":16,"is_preprint":false},{"pmid":"39042920","id":"PMC_39042920","title":"T-cell dysfunction in CLL is mediated through expression of Siglec-10 ligands CD24 and CD52 on CLL cells.","date":"2024","source":"Blood advances","url":"https://pubmed.ncbi.nlm.nih.gov/39042920","citation_count":15,"is_preprint":false},{"pmid":"31507595","id":"PMC_31507595","title":"Specific Sialoforms Required for the Immune Suppressive Activity of Human Soluble CD52.","date":"2019","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/31507595","citation_count":15,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":52013,"output_tokens":7188,"usd":0.13193,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":16479,"output_tokens":5497,"usd":0.10991,"stage2_stop_reason":"end_turn"},"total_usd":0.24184,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1991,\n      \"finding\": \"CD52 (CAMPATH-1/CDw52) is a GPI-anchored glycoprotein with an exceptionally short mature peptide of 12–18 amino acid residues and a single N-linked oligosaccharide at Asn3. The antigenic epitope is heat-stable but sensitive to mild alkali, and the protein is anchored by a glycosylphosphatidylinositol (GPI) anchor as demonstrated by phosphatidylinositol-specific phospholipase C treatment.\",\n      \"method\": \"Protein purification, N-terminal sequencing, PCR-based cDNA cloning, phospholipase C treatment\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct biochemical purification, sequencing, and enzymatic (PLC) functional validation; foundational structural characterization replicated across subsequent studies\",\n      \"pmids\": [\"1711975\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"The antigenic epitope of CD52 recognized by CAMPATH-1 antibodies resides in a proteolytic fragment containing the C-terminal tripeptide and the GPI anchor; proximity of the epitope to the cell membrane (not the N-linked sugar or the first nine amino acids) is the key feature making it an efficient target for complement-mediated lysis. Both native and deglycosylated antigen, as well as proteolytic fragments, can be reincorporated into target cells to confer complement sensitivity.\",\n      \"method\": \"Complement lysis assay, antigen reincorporation into cells, proteolytic fragmentation, deglycosylation\",\n      \"journal\": \"Molecular immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with functional lysis assay and multiple chemical/enzymatic manipulations; replicated in same lab and consistent with structural data\",\n      \"pmids\": [\"8366859\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"CD52 (CDw52/HE5) is expressed at high levels in the male reproductive system (epididymis, seminal vesicle, seminal plasma) and is acquired by maturing (but not testicular) spermatozoa during epididymal transit, representing a novel mechanism of cell-surface antigen acquisition. In the presence of human complement, CAMPATH-1 antibodies inhibit sperm motility; seminal plasma blocks antibody binding and protects sperm.\",\n      \"method\": \"Immunohistochemistry, flow cytometry, sperm motility assay with complement\",\n      \"journal\": \"Journal of reproductive immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization by immunohistochemistry and functional motility assay, single lab, two orthogonal methods\",\n      \"pmids\": [\"7685389\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"The human epididymal gene HE5 encodes the same peptide backbone as the lymphocyte differentiation antigen CDw52 (CD52); both products are transcribed from a single-copy gene, and expression is highly restricted to epithelial cells of the epididymal and deferent duct.\",\n      \"method\": \"Differential cDNA library screening, sequencing, Northern blot, in situ hybridization, Southern blot\",\n      \"journal\": \"Molecular reproduction and development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cDNA sequencing establishing gene identity, in situ hybridization confirming cell-type-specific expression; foundational finding replicated in subsequent studies\",\n      \"pmids\": [\"8418821\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Cross-linking of CD52 on normal resting CD4+ and CD8+ T lymphocytes with anti-CD52 antibodies induces proliferation and lymphokine production in the presence of phorbol esters (or directly with one antibody), and augments anti-CD3-mediated responses when co-immobilized; this activation is inhibited by cyclosporin A, implicating calcineurin-dependent signal transduction pathways. Anti-CD52 antibodies did not synergize with anti-CD2 or anti-CD28, and did not inhibit antigen-specific T cell responses.\",\n      \"method\": \"T cell proliferation assay, lymphokine production assay, cyclosporin A inhibition, co-immobilization of antibodies\",\n      \"journal\": \"International immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean primary T cell functional assays with pharmacological inhibition; single lab, two orthogonal functional readouts\",\n      \"pmids\": [\"7718516\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"CD52 is expressed on the surface of human eosinophils (but not neutrophils) as a GPI-anchored molecule (confirmed by phospholipase C treatment). Cross-linking of CD52 on eosinophils dose-dependently inhibits reactive oxygen species production stimulated by C5a, platelet-activating factor, and GM-CSF, identifying a functional inhibitory role for CD52 on eosinophils.\",\n      \"method\": \"Flow cytometry, RT-PCR, Northern blot, phospholipase C treatment, reactive oxygen species assay\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct biochemical confirmation of GPI anchor by PLC treatment, functional cross-linking assay with multiple stimuli, multiple orthogonal methods in single study\",\n      \"pmids\": [\"8977262\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Cross-linking CD52 on B-cell and Jurkat T-cell lines (but not receptor-mediated stimulation) induces growth inhibition and apoptosis (Fas/FasL-independent pathway in Wien 133 B cells). Cells surviving anti-CD52 treatment down-regulate CD52 and other GPI-anchored molecules (CD59, CD55) but not transmembrane molecules, due to a defect in GPI precursor synthesis; this phenotype is reversible in vitro and in vivo.\",\n      \"method\": \"Cell growth assay, flow cytometry, apoptosis assay, in vivo mouse xenograft\",\n      \"journal\": \"Immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional cross-linking, apoptosis assay with Fas pathway exclusion, in vivo xenograft reversal; single lab\",\n      \"pmids\": [\"9824507\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Male genital tract CD52 differs structurally from lymphocyte CD52: the sperm/seminal plasma form carries mostly 2-inositol palmitoylated, alkylacylglycerol GPI anchors (rendering it resistant to phospholipase C) and highly charged, complex-type N-glycans with lactosamine repeats and peripheral fucose, distinct from the lymphocyte form.\",\n      \"method\": \"Protein purification from seminal plasma, Western blot, structural mass spectrometry of glycans and GPI anchor\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — detailed structural mass spectrometry of purified protein; rigorous biochemical analysis establishing tissue-specific post-translational modification\",\n      \"pmids\": [\"10514467\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"CD52-mediated signal transduction in T cells requires the co-expression of both the T cell receptor (TCR) and the CD45 tyrosine phosphatase at the cell surface; cross-linking of CD52 triggers TCR-dependent protein tyrosine phosphorylation (involving p56lck and p59fyn regulated by CD45) without activating phospholipase Cγ1 or calcium signals. FRET analysis demonstrated CD52 homo-association at the cell surface independent of TCR/CD45, and CD52-TCR association in CD45+TCR+ cells.\",\n      \"method\": \"Protein tyrosine phosphorylation assay in primary T cells and Jurkat subclones transfected with CD52, FRET, pharmacological inhibition\",\n      \"journal\": \"International immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — transfected cell lines with defined genetic backgrounds, FRET for protein associations, multiple orthogonal readouts (phosphorylation, FRET, Ca2+ flux), single lab\",\n      \"pmids\": [\"10744652\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"In a murine ATL model, the major tumor-killing mechanism of alemtuzumab (anti-CD52) in vivo requires Fcγ receptor-containing receptors (e.g., FcγRIII) on polymorphonuclear leukocytes and macrophages, as demonstrated using FcRγ-knockout mice; FcRγ-mediated ADCC and/or cross-linking-induced apoptosis are the primary mechanisms.\",\n      \"method\": \"In vivo NOD/SCID mouse xenograft, FcRγ-knockout mice, survival analysis\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout mouse model with defined phenotypic readout (survival); single lab, single model\",\n      \"pmids\": [\"14559836\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"In a human CD52 transgenic mouse model, alemtuzumab-mediated lymphocyte depletion and cytokine induction are largely independent of complement (cobra venom factor treatment had no impact) but are mediated primarily by neutrophils and NK cells, as demonstrated by antibody depletion of Gr-1+ or asialo-GM-1+ populations.\",\n      \"method\": \"Transgenic mouse model, cobra venom factor complement depletion, antibody depletion of neutrophil (Gr-1) and NK cell (asialo-GM-1) populations, flow cytometry\",\n      \"journal\": \"Immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple genetic/immunological perturbations in defined transgenic model with replicated functional readouts; rigorous controls for both complement and cellular effectors\",\n      \"pmids\": [\"19740383\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Soluble CD52, released from the surface of activated T cells by phospholipase C, binds to the inhibitory receptor Siglec-10 on T cells and suppresses T cell activation by impairing phosphorylation of the TCR-associated kinases Lck and Zap70. Transfer of lymphocyte populations depleted of CD52hi cells into NOD mice substantially accelerated onset of diabetes.\",\n      \"method\": \"Phospholipase C release assay, Siglec-10 binding assay, kinase phosphorylation assay (Lck, Zap70), NOD mouse adoptive transfer\",\n      \"journal\": \"Nature immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct biochemical binding, kinase phosphorylation assays, and in vivo adoptive transfer model; multiple orthogonal methods; published in Nature Immunology\",\n      \"pmids\": [\"23685786\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"CD52-mediated suppression of T cells requires the DAMP protein HMGB1 as an intermediary: soluble CD52 binds specifically to the proinflammatory Box B domain of HMGB1 via its N-linked glycan (α-2,3 sialic acid linkage with galactose), which then promotes binding to Siglec-10. This triggers tyrosine phosphorylation of Siglec-10 and recruitment of SHP1 phosphatase to the intracellular ITIM motif of Siglec-10, which associates with the TCR; T cell suppression was blocked by anti-HMGB1 antibody or Box A domain of HMGB1.\",\n      \"method\": \"CD52-Fc binding assays, HMGB1 domain-specific blocking, co-immunoprecipitation (CD52/HMGB1/Siglec-10/SHP1/TCR complex), Siglec-10 phosphorylation assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution of complex, domain-specific mapping, co-IP of multi-protein complex, phosphorylation assay, blocking experiments; multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"29997173\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Soluble CD52 inhibits Toll-like receptor and TNF receptor signaling to limit NF-κB activation and reduce inflammatory cytokine production in macrophages, monocytes, and dendritic cells. At higher concentrations, soluble CD52 depletes MCL-1, activating BH3-only proteins BAX and BAK to cause intrinsic apoptotic cell death. In vivo, CD52 administration suppresses LPS-induced cytokine secretion, while genetic deletion of CD52 exacerbates LPS responses.\",\n      \"method\": \"NF-κB reporter assays, cytokine measurement, MCL-1/BAX/BAK protein assays, CD52 knockout mice, LPS endotoxic shock model\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockout with defined in vivo phenotype, multiple molecular pathway readouts (NF-κB, MCL-1, BAX/BAK), multiple cell types and orthogonal methods\",\n      \"pmids\": [\"29244050\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CD52 bioactivity (T cell suppression) requires tetra-antennary α-2,3 sialylated N-glycans: removal of α-2,3 sialylation abolishes bioactivity, which is restored by re-sialylation with α-2,3 sialyltransferases. O-glycan core type-2 di-sialylated structures at Ser12 are also enriched in bioactive CD52 fractions.\",\n      \"method\": \"Glycomic analysis (porous graphitized carbon-ESI-MS/MS), glycopeptide analysis (C8-LC-ESI-MS), enzymatic desialylation and re-sialylation, anion exchange fractionation, T cell suppression bioassay\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — enzymatic gain-of-function and loss-of-function (desialylation/re-sialylation) combined with structural mass spectrometry and functional bioassay; multiple orthogonal methods\",\n      \"pmids\": [\"31507595\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"On B cells, surface CD52 functions as a homeostatic inhibitory molecule: CD52-deficient JeKo-1 cells are hyperresponsive to BCR signaling. Antigen-specific BCR activation triggers CD52 cleavage in a phospholipase C-dependent manner, reducing surface CD52. Soluble CD52-Fc inhibits BCR signaling partially through Siglec-10, reduces surface immunoglobulin and CXCR5, and promotes expansion of IgD+IgMlo anergic B cells.\",\n      \"method\": \"CD52-knockout cell line (JeKo-1), BCR signaling assay, phospholipase C inhibition, recombinant CD52-Fc treatment, Siglec-10 blocking, flow cytometry\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function cell line, pharmacological inhibition of PLC, recombinant protein functional assay; single lab, multiple readouts\",\n      \"pmids\": [\"33658999\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"In monocytes, CD52 expression negatively regulates cell adhesion: overexpression of CD52 decreases CD18 levels and monocyte adhesion, while knockdown of CD52 increases monocyte adhesion. CD52 expression is upregulated by IL-4/IL-13 via the STAT6 pathway and downregulated by LPS and type I/II IFNs via JAK1 and HDAC IIa.\",\n      \"method\": \"CD52 overexpression and siRNA knockdown in monocytes, adhesion assay, STAT6/JAK1/HDAC IIa pathway inhibitors, cytokine stimulation\",\n      \"journal\": \"Arthritis & rheumatology (Hoboken, N.J.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bidirectional gain/loss-of-function with defined pathway inhibitors and phenotypic readout; single lab\",\n      \"pmids\": [\"33760395\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Crystal structures of the rat CAMPATH-1G and humanized CAMPATH-1H Fab fragments were solved at 2.6 Å and 3.25 Å resolution, revealing that the antibody-combining site is dominated by LysH52b and LysH53 protrusions from loop H2, and that framework residues H71 and H24 are major determinants of structural differences between rat and humanized antibody loops H1 and H2.\",\n      \"method\": \"X-ray crystallography\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structures of both rat and humanized antibody Fab fragments with detailed structural comparison\",\n      \"pmids\": [\"9811544\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Co-crystal structure of an anti-CD52 antibody Fab with a CD52 peptide mimetic solved at 2.2 Å (PDB 6OBD) revealed that Asn33 of the antibody light chain CDR1 directly contacts the CD52 phosphate group via a hydrogen bond; mutation of Asn33 to Asp (deamidation mimic) reduces antigen binding affinity ~400-fold.\",\n      \"method\": \"X-ray crystallography, site-directed mutagenesis, Biacore binding affinity measurement, CDC assay\",\n      \"journal\": \"mAbs\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure combined with systematic mutagenesis and quantitative binding assays; multiple orthogonal methods in single study\",\n      \"pmids\": [\"31199181\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"CD52-null mice generated by gene disruption are fertile and show normal sperm viability, motility, morphology, and fertilizing ability both in vivo and in vitro, demonstrating that CD52 is not required for fertilization in the mouse despite being a major sperm maturation-associated antigen.\",\n      \"method\": \"Gene knockout (Cd52 null mice), in vitro fertilization, sperm parameter analysis, litter size measurement\",\n      \"journal\": \"Genes to cells : devoted to molecular & cellular mechanisms\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean knockout mouse with comprehensive in vivo and in vitro fertilization phenotyping; negative finding definitively established\",\n      \"pmids\": [\"18782223\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"The GPI anchor of male genital tract CD52 contains 2-inositol palmitoylation that renders the molecule insensitive to phospholipase C cleavage, in contrast to lymphocyte CD52; sperm CD52 is acquired from epididymal secretions and associates with large molecular carriers in seminal plasma during transfer onto spermatozoa.\",\n      \"method\": \"Phospholipase C treatment, flow cytometry, Western blot, size filtration of seminal plasma\",\n      \"journal\": \"Molecular reproduction and development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — PLC treatment establishing anchor modification, filtration experiments, multiple cell/tissue sources; single lab\",\n      \"pmids\": [\"9291477\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CLL cell-derived CD52 (and CD24) expressed on the CLL cell surface suppresses CAR T cell function via Siglec-10 signaling; blocking CD24 and/or CD52 markedly reduced CAR T cell dysfunction upon coculture with resting CLL cells. CD40 stimulation of CLL cells downregulated CD52 expression via SRC kinase signaling (reversed by dasatinib), restoring T cell function.\",\n      \"method\": \"Co-culture assays (CLL + CAR T cells), antibody blocking of CD52/CD24, dasatinib pharmacological inhibition, transcriptome profiling, flow cytometry\",\n      \"journal\": \"Blood advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct antibody blocking establishing functional role, pharmacological pathway dissection; single lab, multiple readouts\",\n      \"pmids\": [\"39042920\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Different glycoforms of CD52 associate differently with lipid microdomains: lymphocyte CD52 (both CAMPATH epitope and O-glycan-bearing glycoforms) resides in cholesterol-rich lipid rafts, whereas in capacitated sperm the O-glycoform associates with GM3-rich microdomains distinct from classical rafts. Heterologous CD52 insertion experiments confirmed the importance of the association between GM3 and O-glycans for specialized microdomain formation.\",\n      \"method\": \"Brij 98 solubilization, sucrose density gradient centrifugation, heterologous CD52 insertion (prostasomes into rat sperm), Western blot\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — biochemical fractionation with heterologous insertion experiment; single lab, two orthogonal approaches\",\n      \"pmids\": [\"16266689\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Activated RAS signaling profoundly promotes surface expression of CD52 on mast cells, as demonstrated in the MCPV-1 cell line generated by lentiviral immortalization. CD52 is expressed at high levels on neoplastic mast cells in advanced systemic mastocytosis but not on normal or indolent SM mast cells.\",\n      \"method\": \"Lentiviral immortalization, functional studies in MCPV-1 cell line, flow cytometry, NSG mouse xenograft\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional cell line model with RAS pathway manipulation; single lab, mechanistic claim about RAS regulation of CD52 expression\",\n      \"pmids\": [\"24760752\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"CD52 expression on sperm is regulated by epididymal maturation: the percentage of sperm expressing CD52 increases progressively from 0.5% in spermatocoeles to 85.7% in the cauda epididymidis, tracking acquisition of motility. CD52 levels on sperm positively correlate with percentage of motile cells, suggesting involvement in sperm maturation.\",\n      \"method\": \"Flow cytometry with CAMPATH-1G, quantitative immunostaining of sperm from different epididymal regions\",\n      \"journal\": \"Molecular human reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct quantitative flow cytometric localization across epididymal regions correlating with functional parameter; single lab\",\n      \"pmids\": [\"9464849\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"CD52 mRNA levels in epididymal cells are regulated post-transcriptionally by temperature: exposure to 37°C (vs. 33°C) rapidly and irreversibly suppresses CD52/CE5 mRNA in a specific manner without affecting other epididymal mRNAs, as shown in dog epididymal cell culture; cycloheximide and DRB experiments suggest mRNA half-life regulation.\",\n      \"method\": \"Epididymal cell culture, Northern blot, temperature shift experiments, cycloheximide and DRB treatment\",\n      \"journal\": \"Endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct experimental manipulation (temperature, inhibitors) in cell culture with specific mRNA quantification; single lab\",\n      \"pmids\": [\"8828507\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Peripheral blood myeloid dendritic cells (lineage−HLA-DR+CD11c+) express CD52 and are depleted by alemtuzumab treatment in patients, while tissue-resident Langerhans cells and dermal-interstitial DCs do not express CD52 under steady-state or inflammatory conditions. Depletion of CD52+ cells from normal PB strongly inhibits allogeneic MLR and primary autologous responses to KLH. CD52 expression is lost during monocyte-derived DC maturation with LPS.\",\n      \"method\": \"Four-color flow cytometry, immunohistochemistry of skin and gut, allogeneic MLR, KLH primary response assay, patient sample analysis before/after alemtuzumab\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization by flow cytometry and IHC with functional MLR assay; replicated across two complementary papers (PMID 12176892, 12393688)\",\n      \"pmids\": [\"12176892\", \"12393688\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CD52 is a GPI-anchored glycoprotein of only 12 mature amino acids bearing a single complex N-linked glycan; when expressed on the lymphocyte surface it can transduce costimulatory signals via TCR/CD45-dependent tyrosine kinase pathways upon cross-linking, while soluble CD52 released by phospholipase C-mediated shedding acts as an immunosuppressant by binding the proinflammatory HMGB1 Box B domain, facilitating engagement of the inhibitory Siglec-10 receptor, and recruiting SHP1 to impair Lck/Zap70 phosphorylation and NF-κB signaling; the immunosuppressive activity requires specific tetra-antennary α-2,3-sialylated N-glycans, the protein is subject to tissue-specific GPI anchor and glycan modifications (especially in the male reproductive tract), and its expression is transcriptionally regulated by androgens, temperature, and cytokine signaling (IL-4/IL-13 via STAT6; IFN/LPS via JAK1 and HDAC IIa).\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CD52 (CAMPATH-1/CDw52) is a GPI-anchored cell-surface glycoprotein with an exceptionally short mature peptide of only 12-18 amino acids carrying a single N-linked oligosaccharide at Asn3, expressed on lymphocytes and other immune cells as well as in the male reproductive tract [#0, #3]. Its proximity to the membrane and GPI anchor make it an efficient target for complement-mediated lysis, the basis for the therapeutic antibody alemtuzumab whose in vivo depleting activity is mediated principally by Fc\\u03b3R-bearing neutrophils, NK cells, and macrophages rather than complement [#1, #9, #10]. On the lymphocyte surface CD52 self-associates and physically couples to the TCR, transducing tyrosine-kinase signals through p56lck/p59fyn in a manner dependent on co-expression of the TCR and the CD45 phosphatase [#8]. CD52 functions as a homeostatic inhibitory molecule: a soluble form released from activated T and B cells by phospholipase C-mediated shedding suppresses lymphocyte activation, requiring tetra-antennary \\u03b1-2,3-sialylated N-glycans for bioactivity [#11, #14, #15]. Mechanistically, soluble CD52 binds the proinflammatory Box B domain of the DAMP protein HMGB1 via its sialylated glycan, which promotes engagement of the inhibitory receptor Siglec-10, triggering Siglec-10 phosphorylation and recruitment of the SHP1 phosphatase to its ITIM, thereby impairing Lck/Zap70 phosphorylation [#12]. CD52 broadly dampens innate inflammatory signaling, inhibiting TLR/TNFR-driven NF-\\u03baB activation and, at high concentrations, depleting MCL-1 to activate BAX/BAK-dependent intrinsic apoptosis, with CD52-knockout mice showing exacerbated LPS responses [#13]. CD52 also exerts inhibitory effects on eosinophil reactive oxygen species production, monocyte adhesion, and B-cell receptor signaling, and its expression is regulated by cytokines (IL-4/IL-13 via STAT6; IFN/LPS via JAK1/HDAC IIa) and RAS signaling [#5, #16, #23]. In the male genital tract CD52 is acquired by maturing spermatozoa during epididymal transit and carries distinct, PLC-resistant palmitoylated GPI anchors and complex N-glycans, but it is dispensable for fertility in the mouse [#2, #7, #19].\",\n  \"teleology\": [\n    {\n      \"year\": 1991,\n      \"claim\": \"Establishing CD52 as a GPI-anchored glycoprotein with a uniquely minimal peptide backbone defined the molecular nature of the CAMPATH-1 antigen and explained its accessibility at the cell surface.\",\n      \"evidence\": \"Protein purification, N-terminal sequencing, cDNA cloning, and PLC treatment\",\n      \"pmids\": [\"1711975\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No endogenous physiological ligand identified at this stage\", \"Function of the short peptide unknown\"]\n    },\n    {\n      \"year\": 1993,\n      \"claim\": \"Localizing the antibody epitope to the C-terminal GPI-proximal region explained why CD52 is an efficient target for complement lysis, and reconstitution showed the antigen can be transferred onto cells to confer sensitivity.\",\n      \"evidence\": \"Complement lysis assay, antigen reincorporation, proteolytic and deglycosylation manipulations\",\n      \"pmids\": [\"8366859\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not address signaling or non-antibody-dependent function\", \"Effector mechanism in vivo not tested\"]\n    },\n    {\n      \"year\": 1993,\n      \"claim\": \"Identification of the epididymal HE5 gene as encoding the same backbone as lymphocyte CDw52 established that a single-copy gene produces CD52 in both immune and male reproductive tissues, while sperm functional assays raised a reproductive role.\",\n      \"evidence\": \"Differential cDNA screening, in situ hybridization, Southern blot, sperm motility assay with complement\",\n      \"pmids\": [\"8418821\", \"7685389\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Causal requirement of CD52 in sperm function not established\", \"Tissue-specific modifications not yet characterized\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Demonstrating that anti-CD52 cross-linking drives T-cell proliferation and lymphokine production in a cyclosporin-sensitive manner first implicated CD52 as a costimulatory signaling molecule rather than an inert antigen.\",\n      \"evidence\": \"Primary T-cell proliferation and lymphokine assays with cyclosporin A inhibition and antibody co-immobilization\",\n      \"pmids\": [\"7718516\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular signaling intermediates not defined\", \"Reliance on antibody cross-linking rather than a natural ligand\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Extending CD52 expression and inhibitory function to eosinophils showed it can dampen innate effector responses, broadening its role beyond lymphocytes.\",\n      \"evidence\": \"Flow cytometry, PLC treatment, and reactive oxygen species assays with multiple stimuli\",\n      \"pmids\": [\"8977262\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Signaling pathway for ROS inhibition not mapped\", \"Endogenous trigger unknown\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Tracking CD52 acquisition across epididymal regions and identifying PLC-resistant palmitoylated GPI anchors revealed tissue-specific post-translational tailoring of the molecule during sperm maturation.\",\n      \"evidence\": \"Quantitative flow cytometry across epididymal regions; PLC treatment, filtration of seminal plasma\",\n      \"pmids\": [\"9464849\", \"9291477\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Correlation with motility not shown to be causal\", \"Carrier identity in seminal plasma undefined\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Showing that anti-CD52 cross-linking induces Fas-independent apoptosis in lymphoid lines, accompanied by loss of GPI biosynthesis, illuminated antibody-induced cell death and a route to antigen-loss escape.\",\n      \"evidence\": \"Cell growth and apoptosis assays, flow cytometry, in vivo xenograft reversal\",\n      \"pmids\": [\"9824507\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking cross-linking to GPI synthesis defect unclear\", \"Relevance to physiological signaling uncertain\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Crystal structures of the rat and humanized CAMPATH Fab fragments defined the antibody-combining site and the framework determinants of humanization, supporting therapeutic antibody engineering.\",\n      \"evidence\": \"X-ray crystallography of CAMPATH-1G and CAMPATH-1H Fab fragments\",\n      \"pmids\": [\"9811544\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure of the antigen-bound complex not resolved here\", \"No insight into CD52 native function\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Demonstrating that CD52 signaling requires both TCR and CD45 and triggers lck/fyn-dependent phosphorylation, with FRET-confirmed CD52 homo-association and CD52-TCR coupling, defined the membrane signaling architecture of surface CD52.\",\n      \"evidence\": \"Tyrosine phosphorylation assays in transfected Jurkat subclones, FRET, pharmacological inhibition\",\n      \"pmids\": [\"10744652\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream transcriptional consequences not mapped\", \"Molecular basis of CD52-TCR association undefined\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"FcR\\u03b3-knockout experiments established that alemtuzumab tumor killing in vivo depends on Fc\\u03b3R-bearing effector cells, redirecting the understanding of its mechanism away from pure complement lysis.\",\n      \"evidence\": \"NOD/SCID xenograft and FcR\\u03b3-knockout mouse survival analysis\",\n      \"pmids\": [\"14559836\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relative contribution of ADCC versus apoptosis not quantified\", \"Single tumor model\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Using human CD52 transgenic mice, depletion was shown to be complement-independent and mediated by neutrophils and NK cells, refining the in vivo effector requirements of alemtuzumab.\",\n      \"evidence\": \"Transgenic model, cobra venom factor complement depletion, antibody depletion of Gr-1+ and asialo-GM-1+ cells\",\n      \"pmids\": [\"19740383\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Human-specific effector contributions may differ\", \"Does not address antigen biology\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identifying soluble CD52 released by PLC as a Siglec-10-binding suppressor of Lck/Zap70 phosphorylation, with CD52hi depletion accelerating diabetes, established CD52 as a regulatory immunosuppressive mediator.\",\n      \"evidence\": \"PLC release assay, Siglec-10 binding, kinase phosphorylation assays, NOD mouse adoptive transfer\",\n      \"pmids\": [\"23685786\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct vs indirect Siglec-10 binding not yet resolved\", \"Glycan dependence not yet defined\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrating that soluble CD52 inhibits TLR/TNFR-driven NF-\\u03baB activation and triggers MCL-1-depletion/BAX-BAK apoptosis at high doses, with CD52-knockout exacerbating LPS responses, defined a broad innate-immune anti-inflammatory role.\",\n      \"evidence\": \"NF-\\u03baB reporters, cytokine measurement, MCL-1/BAX/BAK assays, CD52 knockout mice, LPS shock model\",\n      \"pmids\": [\"29244050\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Receptor mediating innate NF-\\u03baB inhibition not fully resolved\", \"Concentration thresholds in vivo unclear\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Resolving HMGB1 as a glycan-dependent intermediary that bridges soluble CD52 to Siglec-10, driving SHP1 recruitment to the Siglec-10 ITIM associated with the TCR, provided the complete mechanistic chain of CD52-mediated suppression.\",\n      \"evidence\": \"CD52-Fc binding, HMGB1 domain-specific blocking, multi-protein co-IP, Siglec-10 phosphorylation assays\",\n      \"pmids\": [\"29997173\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry of the CD52/HMGB1/Siglec-10 complex undefined\", \"In vivo requirement of HMGB1 not tested\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Showing that bioactivity strictly requires tetra-antennary \\u03b1-2,3-sialylated N-glycans, with loss and enzymatic restoration of function, established the glycan code underlying CD52 immunosuppression.\",\n      \"evidence\": \"Glycomic mass spectrometry, enzymatic desialylation/re-sialylation, T-cell suppression bioassay\",\n      \"pmids\": [\"31507595\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Glycosyltransferases producing bioactive glycoform in vivo unidentified\", \"Role of O-glycans at Ser12 not functionally isolated\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Extending the inhibitory model to B cells and monocytes showed CD52 restrains BCR signaling (partly via Siglec-10) and monocyte adhesion, and identified IL-4/IL-13-STAT6 and IFN/LPS-JAK1/HDAC IIa as regulators of its expression.\",\n      \"evidence\": \"CD52-knockout JeKo-1 cells, BCR signaling and adhesion assays, recombinant CD52-Fc, pathway inhibitors\",\n      \"pmids\": [\"33658999\", \"33760395\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether the same HMGB1/Siglec-10 axis operates in B cells and monocytes not fully established\", \"Adhesion mechanism (CD18 regulation) not molecularly traced\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrating that CLL-derived CD52 suppresses CAR T-cell function via Siglec-10, reversible by CD40/SRC-mediated downregulation, extended the inhibitory axis to a tumor immune-evasion mechanism with therapeutic implications.\",\n      \"evidence\": \"CLL/CAR T co-culture, CD52/CD24 antibody blocking, dasatinib inhibition, transcriptome profiling\",\n      \"pmids\": [\"39042920\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relative contribution of CD52 versus CD24 not isolated\", \"Single-lab co-culture system\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The endogenous receptor(s) and signaling mechanism mediating surface CD52 costimulation, the physiological trigger and in vivo relevance of the HMGB1/Siglec-10 suppressive axis across cell types, and the in vivo enzymes generating bioactive glycoforms remain to be integrated into a single model.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structure of native CD52 bound to HMGB1 or Siglec-10\", \"Reconciliation of costimulatory surface signaling with inhibitory soluble signaling unresolved\", \"Physiological function of reproductive-tract CD52 unknown given fertility of knockout mice\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [8, 11, 12]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [11, 12, 13, 15]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 5, 8]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [11, 7, 12]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [8, 11, 12, 13]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [8, 12, 13]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [6, 13]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"SIGLEC10\", \"HMGB1\", \"PTPN6\", \"TCR\", \"CD45\", \"LCK\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}