{"gene":"CD55","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":1994,"finding":"CD55 (DAF) functions as a complement regulator by inhibiting C3/C5 convertase formation, acting as a species-restricting factor at the level of C3/C5 activation. The third short consensus repeat (SCR3) of DAF is responsible for its complement regulatory activity and signaling.","method":"Functional review synthesizing biochemical and molecular cloning data; SCR domain analysis","journal":"The Journal of laboratory and clinical medicine","confidence":"High","confidence_rationale":"Tier 1 / Strong — molecular cloning combined with domain-level functional analysis, widely replicated across multiple studies in the field","pmids":["7511675"],"is_preprint":false},{"year":1994,"finding":"CD55 is a GPI-anchored protein associated with tyrosine kinases on the inner leaflet of the plasma membrane, enabling signal transduction despite lacking a transmembrane domain.","method":"Biochemical association studies; GPI anchor characterization","journal":"The Journal of laboratory and clinical medicine","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — biochemical association data reported in a review, replicated conceptually in subsequent immunoprecipitation studies","pmids":["7511675"],"is_preprint":false},{"year":1991,"finding":"CD55 co-immunoprecipitates with CD59 and a common 80-kDa glycoprotein from detergent lysates, forming noncovalent membrane complexes. These CD55/CD59/80-kDa complexes contain protein kinase activity, linking GPI-anchored CD55 to intracellular signaling.","method":"Co-immunoprecipitation from HPB ALL cell line detergent lysates; identification of protein kinase activity in immune complexes","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single Co-IP/pulldown with kinase activity assay, single lab but two orthogonal methods","pmids":["1715364"],"is_preprint":false},{"year":1996,"finding":"CD55 (DAF) is the HeLa cell receptor for Enterovirus 70 (EV70). Anti-DAF monoclonal antibodies inhibited EV70 binding to HeLa cells; stable expression of human DAF in murine NIH 3T3 cells conferred EV70 binding and supported virus replication.","method":"Monoclonal antibody blocking assay; heterologous expression of human DAF in NIH 3T3 cells; radiolabeled virus binding assay; immunoprecipitation","journal":"Journal of virology","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution via heterologous expression plus antibody inhibition plus radiolabeled binding, multiple orthogonal methods in one study","pmids":["8764022"],"is_preprint":false},{"year":1998,"finding":"Cardiovirulent Group B Coxsackievirus 3 (CVB3) uses CD55 (DAF) as an attachment receptor. Anti-DAF monoclonal antibodies directed against SCR2 and SCR3 domains most effectively blocked virus binding and infection. Virus binding was reduced by phosphatidylinositol phospholipase C treatment that removes GPI-anchored DAF. Virus binding and internalization were associated with DAF down-regulation at the cell surface.","method":"Monoclonal antibody blocking assay; phospholipase C treatment to deplete GPI-anchored DAF; flow cytometry; competitive binding assays","journal":"Virology","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple orthogonal methods (antibody blocking, enzymatic GPI removal, flow cytometry, competitive binding), identifying SCR2/3 as the binding domain","pmids":["9601501"],"is_preprint":false},{"year":1998,"finding":"CD55 associates with a specific 43-kDa DAF-associated protein (identified by mAb 2E12-G7) that acts as a signal transducer. Cross-linking of DAF via its associated 43-kDa protein induced tyrosine phosphorylation of proteins of 45, 72, 78 and ~100 kDa in peripheral blood mononuclear cells. This 43-kDa antigen was present in CD55 but not CD59 immunoprecipitates, indicating specific association.","method":"Affinity purification of DAF-associated proteins; monoclonal antibody generation; co-immunoprecipitation; surface biotinylation and immunoblotting; tyrosine phosphorylation assay with [gamma-32P]ATP","journal":"International immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal immunoprecipitation plus functional phosphorylation assay, single lab","pmids":["9620603"],"is_preprint":false},{"year":1999,"finding":"Mouse DAF (CD55) exists in multiple isoforms generated by alternative splicing, including GPI-anchored and transmembrane forms encoded by separate genes (Daf-GPI and Daf-TM). Stable expression of either TM or GPI-anchored mouse DAF in CHO cells reduced C3b deposition and protected cells from complement-mediated lysis in a cell-lysis assay. Soluble recombinant mouse DAF inhibited complement in a haemolytic assay.","method":"Molecular cloning; stable transfection of CHO cells; C3b deposition assay; cell lysis assay; haemolytic assay with soluble recombinant DAF","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution via heterologous expression, functional complement inhibition confirmed by multiple assays in one study","pmids":["10417349"],"is_preprint":false},{"year":1999,"finding":"CD55 is a specific cellular ligand for the seven-transmembrane receptor CD97, and this receptor-ligand pair is expressed on fibroblast-like synoviocytes (FLS) and macrophages respectively in synovial tissue, suggesting a role in mediating FLS-macrophage interactions and maintaining synovial architecture.","method":"Immunohistochemical analysis of synovial biopsy specimens; ELISA for soluble CD97 in synovial fluid","journal":"Arthritis and rheumatism","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — immunohistochemistry plus ELISA establishing expression pattern; ligand identity for CD97 based on prior published binding data referenced in the paper","pmids":["10211878"],"is_preprint":false},{"year":2003,"finding":"Exosomes derived from antigen-presenting cells express GPI-anchored CD55 and CD59 but not the transmembrane protein CD46. Antibody blockade of CD55 in the presence of sensitizing antibody and human serum resulted in increased C3b deposition and significantly increased exosome lysis, demonstrating that CD55 on exosomes functionally protects them from complement-mediated lysis.","method":"Flow cytometry of exosome surface proteins; antibody blocking experiments; C3b deposition assay; lysis assay","journal":"European journal of immunology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — functional antibody-blocking experiment with defined complement readouts (C3b deposition and lysis), multiple orthogonal measures in one study","pmids":["12645951"],"is_preprint":false},{"year":2005,"finding":"CD55 (DAF) suppresses adaptive T cell immune responses in vivo. Daf1-/- mice showed significantly enhanced T cell responses to immunization, characterized by hypersecretion of IFN-γ and IL-2 and down-regulation of IL-10. This was complement-dependent: disabling complement in Daf1-/- mice normalized T cell cytokine secretion. CD55 deficiency also exacerbated EAE disease severity, which was also complement-dependent.","method":"Daf1 knockout mouse model; active immunization with antigen; in vitro lymphocyte restimulation cytokine assays; EAE model with complement inhibition","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO with defined cellular phenotype, genetic and pharmacologic complement inhibition as epistasis, two disease models, multiple labs' models referenced","pmids":["15710649"],"is_preprint":false},{"year":2009,"finding":"In nonpolarized HeLa cells, DAF-binding CVB3 entry requires dynamin and lipid rafts but not caveolin, clathrin, or endosomal acidification. Unlike in polarized Caco-2 cells, CVB3 entered HeLa cells with CAR (not DAF-mediated entry). Tyrosine kinase inhibition blocked an early infection event but did not prevent virus entry, indicating DAF-mediated tyrosine kinase signaling is not required for entry into nonpolarized cells.","method":"Dominant-negative proteins; siRNA knockdown of endocytic pathway components; pharmacologic inhibitors; immunofluorescence microscopy","journal":"Journal of virology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic and pharmacologic perturbations of specific endocytic pathways, single lab","pmids":["19710132"],"is_preprint":false},{"year":2010,"finding":"Deletion of CD55 ameliorates arthritis in collagen-induced and K/BxN serum-transfer mouse models, demonstrating that CD55 interaction with CD97 on infiltrating macrophages plays a pathogenic role in RA beyond its complement-inhibitory function. Similarly, CD97-/- mice had reduced arthritis, consistent with the CD55/CD97 axis driving disease.","method":"CD55-/- and CD97-/- mouse models; collagen-induced arthritis; K/BxN serum transfer arthritis model; clinical and immunohistochemical evaluation","journal":"Arthritis and rheumatism","confidence":"High","confidence_rationale":"Tier 2 / Strong — two independent knockout mouse lines in two distinct arthritis models, complementary genetic evidence for CD55/CD97 pathway","pmids":["20131275"],"is_preprint":false},{"year":2015,"finding":"CD55 produced by fibroblast-like synoviocytes (FLS) is deposited on collagen type I and III reticular fibers in the synovial extracellular matrix; this ECM-associated CD55 is resistant to phospholipase C cleavage and co-localizes with complement C3. CD55 deficiency on a FcγRIIB-null background exaggerated K/BxN-induced arthritis, indicating that ECM-deposited CD55 protects synovial tissue from immune complex-mediated complement attack.","method":"Confocal microscopy co-localization; in situ hybridization; flow cytometry; phospholipase C treatment; K/BxN serum transfer arthritis model in CD55/Fcgr2b double-deficient mice; 3D FLS micromass culture","journal":"Arthritis research & therapy","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (confocal co-localization, enzymatic resistance assay, in vivo genetic model) establishing ECM localization and functional consequence","pmids":["25596646"],"is_preprint":false},{"year":2017,"finding":"Biallelic loss-of-function mutations in CD55 cause loss of CD55 protein expression, leading to increased complement activation on T lymphocytes with surface deposition of complement and generation of soluble C5a, defective CD55-mediated costimulatory function, and defective cytokine modulation. Genetic reconstitution of CD55 or treatment with a complement-inhibitory antibody reversed abnormal complement activation (CHAPLE syndrome).","method":"Whole-exome sequencing; functional assays on patients' T lymphocytes (complement deposition, C5a generation); exogenous induction of CD55 expression for genetic reconstitution; complement-inhibitory antibody treatment","journal":"The New England journal of medicine","confidence":"High","confidence_rationale":"Tier 1 / Strong — loss-of-function human genetics combined with functional reconstitution and pharmacologic rescue, multiple mechanistic readouts","pmids":["28657829"],"is_preprint":false},{"year":2017,"finding":"In endometrioid cancer, CD55 functions in a complement-independent manner requiring lipid raft localization. CD55 regulates cancer stem cell self-renewal and core pluripotency genes via ROR2/JNK signaling, and in parallel regulates cisplatin resistance via lymphocyte-specific protein tyrosine kinase (LCK) signaling, which induces DNA repair genes. These represent a bifurcating signaling axis downstream of CD55.","method":"Comparative CSC vs non-CSC analysis; lipid raft disruption; ROR2/JNK pathway inhibition; LCK inhibitor (saracatinib) treatment; gene expression analysis of pluripotency and DNA repair genes; loss-of-function knockdown","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (lipid raft disruption, kinase pathway inhibition, KD with defined molecular readouts) establishing two parallel signaling axes in one study","pmids":["28838952"],"is_preprint":false},{"year":2016,"finding":"Hepatitis C virus (HCV) infection induces expression of a secreted isoform of CD55 (sCD55) generated by alternative splicing. Conditioned medium from HCV-infected hepatocytes and serum from chronically HCV-infected patients inhibited C3 convertase activity and complement-dependent cytolysis; CD55-blocking antibody inhibited this effect, implicating sCD55 in impairment of complement function.","method":"HCV infection/replicon system; RT-PCR for sCD55 splice variant; C3 convertase inhibition assay; complement-dependent cytolysis assay of sheep erythrocytes; antibody blocking","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional complement assays with antibody blocking establishing sCD55's role, single lab with multiple orthogonal methods","pmids":["27357152"],"is_preprint":false},{"year":2016,"finding":"Parainfluenza virus 5 (PIV5) incorporates functional CD55 (and CD46) into virions during assembly. CD55-containing PIV5 virions were highly resistant to complement-mediated neutralization; CD46-containing PIV5 was not. PIV5 infection upregulated cell surface CD55 expression (further enhanced by TNF-α), and virus derived from higher CD55-expressing cells was more complement-resistant in vitro.","method":"Virion protein analysis; complement-mediated neutralization assay comparing CD55-incorporating vs non-incorporating virions; flow cytometry of infected cell surface CD55","journal":"Virology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional neutralization assay with virions selectively incorporating CD55, single lab","pmids":["27505156"],"is_preprint":false},{"year":2017,"finding":"HPV E6 protein expression dramatically enriches the CD55+ subpopulation in cervical cancer cells. The CD55+ subpopulation shows enhanced sphere-forming ability, tumourigenicity, cell migration, and radioresistance. CRISPR/Cas9 knockout of CD55 in HPV-E6-overexpressing cells abolished tumourigenic effects of the E6 protein, placing CD55 downstream of E6 in a pathway promoting cervical cancer aggressiveness.","method":"CRISPR/Cas9 CD55 knockout; ectopic HPV-E6 expression; flow cytometry of CD55+ subpopulations; sphere formation assay; in vitro and in vivo tumourigenicity assay; radiation treatment assay","journal":"The Journal of pathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPR KO with defined molecular/phenotypic readout epistasis to E6, single lab with multiple assays","pmids":["28944962"],"is_preprint":false},{"year":2020,"finding":"ST3GAL1-mediated O-linked sialylation of CD55 is required for CD55's immune-evasion function in breast cancer. ST3GAL1 silencing shifted the O-glycan profile of CD55 from disialylated core 2 to nonsialylated core 1 structures without affecting N-glycans. O-desialylation of CD55 resulted in increased C3 deposition, increased complement-mediated lysis, and enhanced sensitivity to antibody-dependent cell-mediated cytotoxicity.","method":"ST3GAL1 siRNA knockdown; tandem mass spectrometry of N- and O-linked oligosaccharides of CD55; C3 deposition assay; complement-mediated lysis assay; ADCC assay","journal":"Cancer immunology research","confidence":"High","confidence_rationale":"Tier 1 / Strong — detailed glycan structural analysis by mass spectrometry combined with functional complement assays, multiple orthogonal methods in one study","pmids":["33177111"],"is_preprint":false},{"year":2021,"finding":"CD55 on human erythrocytes is specifically required for internalization of Plasmodium falciparum parasites, not for pre-invasion kinetics, erythrocyte deformability, or echinocytosis. CRISPR-Cas9 editing to ablate CD55, antibody-based inhibition, and live cell imaging showed that parasites attached normally to CD55-null erythrocytes but entry was inhibited. CD55 acts after rhoptry discharge and appears to play a role in stability and/or progression of the moving junction.","method":"CRISPR-Cas9 editing of erythrocyte CD55; antibody-based inhibition; live cell imaging; deformability and echinocytosis assays","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Strong — genetic ablation plus antibody inhibition plus live imaging, multiple orthogonal methods identifying specific step of invasion","pmids":["34028351"],"is_preprint":false},{"year":2016,"finding":"CD55 is a transcriptional target of HIF-2α in neuroblastoma cells. HIF-2α expression is sufficient to sustain stem-like features, while CD55 protein specifically contributes to colony growth and cell invasion but not stemness. CD55-positive populations display pro-invading and anti-adhesive properties.","method":"HIF-2α gain-of-function; CD55 functional characterization in CD55-positive vs CD55-negative subpopulations; colony formation and invasion assays","journal":"Oncogenesis","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — functional characterization of CD55-positive cells with separation of invasion from stemness, single lab","pmids":["27043658"],"is_preprint":false},{"year":2016,"finding":"HIF-1α negatively regulates CD55 expression in airway epithelial cells. Hypoxia down-regulated CD55 on small-airway epithelial cells in vitro and in murine lungs in vivo, associated with local complement activation. Pharmacologic inhibition or siRNA silencing of HIF-1α during hypoxia recovered CD55 expression; HIF-1α overexpression down-regulated CD55.","method":"Pharmacologic HIF-1α inhibition; HIF-1α gene silencing; HIF-1α overexpression; in vivo murine hypoxia model; complement activation assay","journal":"American journal of respiratory cell and molecular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — bidirectional manipulation (inhibition and overexpression) of HIF-1α both in vitro and in vivo with defined CD55 and complement outcome measures","pmids":["27494303"],"is_preprint":false},{"year":2022,"finding":"EGFR/Wnt signaling induces β-catenin-mediated lncRNA LINC00973 expression, which sponges miR-216b (targeting CD55) and miR-150 (targeting CD59), resulting in upregulated CD55/CD59 that suppresses the complement system and CD8+ T cell activation. CD55/CD59-neutralizing antibody treatment or LINC00973 promoter mutation activated complement and CD8+ T cells and inhibited tumor growth; combined anti-CD55/CD59 and anti-PD-1 treatment showed synergistic tumor-inhibiting effects.","method":"EGFR/Wnt/β-catenin pathway manipulation; LINC00973 promoter mutation; miRNA sponging mechanism validation; complement activation assay; CD8+ T cell activation assay; antibody neutralization; anti-PD-1 combination therapy in vivo","journal":"Nature cancer","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple genetic perturbations of upstream pathway with mechanistic miRNA sponge mechanism plus functional complement and immune readouts, in vitro and in vivo","pmids":["36271172"],"is_preprint":false},{"year":2019,"finding":"Bee venom upregulates CD55 mRNA and protein in THP-1 cells via ERK phosphorylation. CD55 induction by bee venom inactivates complement as measured by C3 convertase activity. In an AD mouse model, CD55 was decreased and C3C/MAC were elevated; bee venom treatment reversed these changes and alleviated AD symptoms.","method":"mRNA/protein expression analysis; ERK phosphorylation assay; complement-dependent cytotoxicity assay; bacteria-killing assay; in vivo AD mouse model with bee venom treatment","journal":"Toxins","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — ERK-CD55 signaling link with functional complement readout, single lab with in vitro and in vivo evidence","pmids":["31027358"],"is_preprint":false},{"year":2006,"finding":"CD55 (DAF) promotes CD1d expression on macrophages during CVB3 H3 infection and is required for activation of Vγ4+ T cells that mediate myocarditis. DAF-/- mice showed reduced CD1d expression and few Vγ4+IFNγ+ cells; the immunopathogenic mechanism differs in DAF-/- animals (CD8+ T cell depletion aggravates rather than protects disease), establishing CD55 as required for the CD1d/Vγ4+ T cell pathway of CVB3-induced myocarditis.","method":"DAF-/- mouse infection model; CD1d expression analysis; Vγ4+ T cell depletion; CD8+ T cell depletion; IFN-γ intracellular staining","journal":"Viral immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO model with mechanistic T-cell depletion epistasis experiments, single lab","pmids":["16817758"],"is_preprint":false},{"year":2002,"finding":"VEGF upregulates CD55 expression at the cell surface and within the extracellular matrix of endothelial cells (HUVEC). MMP-7 releases intact, functionally active CD55 from ECM, whereas papain degrades it and collagenase fails to release it, establishing that metalloproteinase-mediated shedding generates soluble functional CD55 in the tumor environment.","method":"VEGF stimulation of HUVEC; flow cytometry; ECM CD55 quantification; complement functional assay; protease treatment (papain, collagenase, MMP-7) of ECM-bound CD55","journal":"Tissue antigens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional complement assay confirming activity of released CD55 combined with specific protease release experiments, single lab","pmids":["12445304"],"is_preprint":false}],"current_model":"CD55 (DAF) is a GPI-anchored complement regulator that accelerates decay of C3 and C5 convertases primarily through its third short consensus repeat (SCR3), protecting host cells, exosomes, and ECM from complement-mediated attack; beyond complement regulation, CD55 serves as a receptor for multiple enteroviruses (EV70, CVB3) and the malaria parasite (mediating P. falciparum internalization at the moving junction), acts as a ligand for the adhesion receptor CD97 to modulate cell–cell interactions and inflammatory responses, transduces intracellular signals via associated tyrosine kinases and downstream ROR2/JNK and LCK pathways to drive cancer stem cell self-renewal and chemoresistance, and has its expression regulated transcriptionally by HIF-1α/HIF-2α and post-translationally by ST3GAL1-mediated O-linked sialylation, which controls its complement-inhibitory efficacy in tumors."},"narrative":{"mechanistic_narrative":"CD55 (DAF) is a GPI-anchored cell-surface glycoprotein whose core function is regulation of the complement cascade, accelerating decay of C3/C5 convertases to protect host cells from complement-mediated attack, an activity localized to its third short consensus repeat (SCR3) [PMID:7511675, PMID:10417349]. This protective coat operates not only on cells but also on antigen-presenting-cell exosomes and, in a phospholipase-C-resistant ECM-deposited form on collagen fibers, on synovial tissue, shielding these compartments from C3b deposition and lysis [PMID:12645951, PMID:25596646]. Biallelic loss-of-function mutations in CD55 cause CHAPLE syndrome, a human disease of unchecked complement activation on T lymphocytes with C5a generation that is reversed by genetic reconstitution or complement-inhibitory antibody [PMID:28657829]. Beyond complement, CD55 transduces intracellular signals despite lacking a transmembrane domain by associating with plasma-membrane tyrosine kinases and a 43-kDa signal-transducing partner, driving tyrosine phosphorylation cascades [PMID:7511675, PMID:1715364, PMID:9620603]; in cancer this manifests as complement-independent, lipid-raft-dependent signaling through ROR2/JNK to sustain cancer stem cell self-renewal and through LCK to confer chemoresistance [PMID:28838952]. CD55 also serves as a cellular receptor for Enterovirus 70 and Coxsackievirus B3 (via SCR2/SCR3) and is specifically required for Plasmodium falciparum erythrocyte internalization at the moving junction [PMID:8764022, PMID:9601501, PMID:34028351], and acts as the ligand for the adhesion GPCR CD97, an interaction that drives macrophage-mediated arthritis pathology [PMID:10211878, PMID:20131275]. CD55 expression and complement-inhibitory efficacy are tightly regulated: transcriptionally by HIF-1α (repressive) and HIF-2α (inductive) under hypoxia and by an EGFR/Wnt/β-catenin–LINC00973 axis, and post-translationally by ST3GAL1-mediated O-sialylation that controls its tumor immune-evasion capacity [PMID:27494303, PMID:27043658, PMID:36271172]. In vivo, CD55 restrains adaptive T cell responses in a complement-dependent manner [PMID:15710649].","teleology":[{"year":1994,"claim":"Established the foundational function of CD55 as a complement regulator and mapped the activity to a defined structural module, answering where in the protein complement inhibition resides.","evidence":"Functional review synthesizing molecular cloning and SCR domain analysis localizing activity to SCR3","pmids":["7511675"],"confidence":"High","gaps":["Atomic-level mechanism of convertase decay acceleration not resolved here","Relative contributions of SCR2 vs SCR3 to different ligand interactions not delineated"]},{"year":1991,"claim":"Addressed how a GPI-anchored protein lacking a cytoplasmic tail could signal, by showing CD55 forms noncovalent membrane complexes with CD59 and an 80-kDa glycoprotein carrying protein kinase activity.","evidence":"Co-immunoprecipitation from HPB ALL detergent lysates with kinase activity assay","pmids":["1715364"],"confidence":"Medium","gaps":["Identity of the 80-kDa glycoprotein and kinase not defined","Single cell line, single lab"]},{"year":1998,"claim":"Refined the signaling model by identifying a specific 43-kDa DAF-associated transducer whose cross-linking elicits a defined tyrosine phosphorylation cascade.","evidence":"Affinity purification, reciprocal co-immunoprecipitation, and tyrosine phosphorylation assay in PBMCs","pmids":["9620603"],"confidence":"Medium","gaps":["Molecular identity of the 43-kDa protein unestablished","Downstream physiologic consequence of the phosphorylation events unclear"]},{"year":1996,"claim":"Demonstrated CD55 is a bona fide viral receptor by reconstituting EV70 binding and replication in heterologous murine cells, opening a non-complement role for the protein.","evidence":"Anti-DAF antibody blocking, heterologous expression in NIH 3T3, radiolabeled virus binding","pmids":["8764022"],"confidence":"High","gaps":["Whether CD55 alone suffices for entry vs requires co-receptors not addressed","Binding domain not mapped in this study"]},{"year":1998,"claim":"Extended viral receptor use to CVB3 and mapped the binding determinant to SCR2/SCR3, linking the receptor surface to specific structural repeats.","evidence":"Domain-specific antibody blocking, PI-PLC GPI removal, flow cytometry, competitive binding","pmids":["9601501"],"confidence":"High","gaps":["Overlap between virus-binding and complement-regulatory surfaces not fully separated","Internalization mechanism not defined here"]},{"year":1999,"claim":"Confirmed by gain-of-function reconstitution that CD55, in both GPI and transmembrane isoforms, is sufficient to inhibit complement and protect cells from lysis.","evidence":"Cloning and stable CHO expression with C3b deposition, cell lysis, and hemolytic assays","pmids":["10417349"],"confidence":"High","gaps":["Functional differences between TM and GPI isoforms in vivo not resolved","Mouse-human isoform divergence may limit translation"]},{"year":1999,"claim":"Identified CD55 as the ligand for the seven-transmembrane receptor CD97 and placed this pair in synovial tissue, suggesting a complement-independent adhesion/inflammation role.","evidence":"Immunohistochemistry of synovium and ELISA for soluble CD97","pmids":["10211878"],"confidence":"Medium","gaps":["Direct functional consequence of CD55-CD97 binding not tested here","Binding affinity and stoichiometry not measured"]},{"year":2003,"claim":"Showed CD55's protective function extends beyond cells to APC-derived exosomes, broadening the substrate range of complement regulation.","evidence":"Flow cytometry of exosome surface proteins with antibody blocking, C3b deposition and lysis assays","pmids":["12645951"],"confidence":"High","gaps":["In vivo relevance of exosomal CD55 protection not established","Mechanism of CD55 sorting onto exosomes unknown"]},{"year":2005,"claim":"Established a physiologic immunoregulatory role by showing CD55 restrains adaptive T cell cytokine responses in a complement-dependent manner.","evidence":"Daf1-/- mice with immunization, cytokine restimulation assays, and EAE model with complement disabling","pmids":["15710649"],"confidence":"High","gaps":["Cellular target (T cell intrinsic vs APC) of complement effect not fully separated","Human relevance inferred from mouse"]},{"year":2006,"claim":"Revealed a complement-independent immunopathogenic role, showing CD55 is required for the CD1d/Vγ4+ T cell pathway driving CVB3 myocarditis.","evidence":"DAF-/- infection model with CD1d analysis and T cell subset depletions","pmids":["16817758"],"confidence":"Medium","gaps":["Molecular link between CD55 and CD1d induction unknown","Single lab"]},{"year":2002,"claim":"Defined how soluble, functionally active CD55 is generated in tissue by showing VEGF induces ECM CD55 and MMP-7 specifically releases it intact.","evidence":"VEGF stimulation of HUVEC, ECM quantification, complement assay, protease release experiments","pmids":["12445304"],"confidence":"Medium","gaps":["In vivo contribution of MMP-7-released CD55 to tumor complement evasion not shown","Single lab"]},{"year":2010,"claim":"Demonstrated genetically that the CD55-CD97 axis drives arthritis pathology independent of complement, validating the receptor-ligand interaction functionally.","evidence":"CD55-/- and CD97-/- mice in collagen-induced and K/BxN serum-transfer arthritis models","pmids":["20131275"],"confidence":"High","gaps":["Downstream macrophage signaling from CD97 engagement not detailed","Relative weight of adhesion vs complement roles not quantified"]},{"year":2015,"claim":"Showed FLS-produced CD55 is deposited on synovial ECM collagen in a PI-PLC-resistant form that protects tissue from immune-complex-driven complement attack.","evidence":"Confocal co-localization, in situ hybridization, PLC resistance assay, K/BxN arthritis in CD55/Fcgr2b double-deficient mice","pmids":["25596646"],"confidence":"High","gaps":["Molecular mechanism anchoring CD55 to collagen unknown","Whether ECM CD55 also engages CD97 not addressed"]},{"year":2017,"claim":"Defined CD55 as a human disease gene, establishing CHAPLE syndrome as a complement dysregulation disorder caused by CD55 loss and reversible by complement inhibition.","evidence":"Whole-exome sequencing, patient T lymphocyte functional assays, genetic reconstitution and antibody rescue","pmids":["28657829"],"confidence":"High","gaps":["Mechanism of CD55's costimulatory function distinct from complement decay not resolved","Genotype-phenotype variability not detailed"]},{"year":2017,"claim":"Uncovered a complement-independent, lipid-raft-dependent signaling output of CD55 that bifurcates into ROR2/JNK-driven stemness and LCK-driven chemoresistance in cancer.","evidence":"Lipid raft disruption, ROR2/JNK and LCK pathway inhibition, knockdown with pluripotency and DNA-repair gene readouts","pmids":["28838952"],"confidence":"High","gaps":["How CD55 physically activates ROR2 and LCK at the raft is unknown","Generality across tumor types beyond endometrioid not established"]},{"year":2017,"claim":"Placed CD55 downstream of an oncogenic driver, showing HPV-E6 enriches a tumourigenic CD55+ cell population that requires CD55 for its aggressive phenotype.","evidence":"CRISPR/Cas9 CD55 knockout, ectopic E6 expression, sphere/tumourigenicity/radioresistance assays","pmids":["28944962"],"confidence":"Medium","gaps":["Mechanism by which E6 enriches CD55+ cells unknown","Single lab"]},{"year":2016,"claim":"Showed transcriptional control of CD55 by hypoxia factors, with HIF-1α repressing CD55 in airway epithelium to permit local complement activation.","evidence":"Bidirectional HIF-1α manipulation in vitro and in vivo murine hypoxia with complement readouts","pmids":["27494303"],"confidence":"High","gaps":["Direct vs indirect promoter regulation by HIF-1α not dissected","Tissue specificity of repression vs induction unexplained"]},{"year":2016,"claim":"Demonstrated HIF-2α drives CD55 expression in neuroblastoma and that CD55 contributes specifically to invasion and colony growth rather than stemness, separating CD55's roles from the HIF-2α stemness program.","evidence":"HIF-2α gain-of-function and functional comparison of CD55-positive vs negative subpopulations","pmids":["27043658"],"confidence":"Medium","gaps":["Apparent opposite-direction HIF regulation vs airway epithelium unreconciled","Single lab"]},{"year":2016,"claim":"Showed pathogens exploit CD55 for complement evasion, with HCV inducing a secreted CD55 splice isoform that inhibits C3 convertase systemically.","evidence":"HCV replicon system, RT-PCR splice detection, C3 convertase and cytolysis assays with antibody blocking","pmids":["27357152"],"confidence":"Medium","gaps":["Cellular source of patient serum sCD55 not pinpointed","Single lab"]},{"year":2016,"claim":"Showed enveloped viruses physically incorporate functional CD55 into virions to resist complement neutralization, a host-protein-hijacking evasion mechanism.","evidence":"Virion protein analysis and complement neutralization comparing CD55-incorporating vs non-incorporating PIV5","pmids":["27505156"],"confidence":"Medium","gaps":["Mechanism of selective CD55 vs CD46 incorporation unknown","Single lab"]},{"year":2020,"claim":"Established that O-linked sialylation by ST3GAL1 is required for CD55's complement-inhibitory immune-evasion function, defining a post-translational control point.","evidence":"ST3GAL1 knockdown, mass spectrometry of CD55 glycans, C3 deposition, lysis, and ADCC assays","pmids":["33177111"],"confidence":"High","gaps":["Structural basis for how sialic acid affects convertase decay unknown","Generality beyond breast cancer not tested"]},{"year":2021,"claim":"Pinpointed the precise step of malaria invasion requiring CD55, showing it acts after rhoptry discharge in moving junction stability rather than in attachment.","evidence":"CRISPR-Cas9 erythrocyte CD55 ablation, antibody inhibition, live cell imaging, deformability/echinocytosis controls","pmids":["34028351"],"confidence":"High","gaps":["Direct parasite ligand for CD55 at the junction not identified","Molecular basis of junction stabilization unresolved"]},{"year":2022,"claim":"Defined an oncogenic non-coding RNA circuit that upregulates CD55 to suppress complement and CD8+ T cells, and showed therapeutic synergy of CD55 blockade with checkpoint inhibition.","evidence":"EGFR/Wnt/β-catenin manipulation, LINC00973 promoter mutation, miRNA sponge validation, complement and T cell assays, anti-PD-1 combination in vivo","pmids":["36271172"],"confidence":"High","gaps":["Relative contribution of CD55 vs CD59 to the immune suppression not separated","Clinical translatability of combination therapy untested"]},{"year":2019,"claim":"Linked an ERK-dependent stimulus to CD55 induction and complement 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produce virions with enhanced resistance to complement-mediated neutralization.","date":"2016","source":"Virology","url":"https://pubmed.ncbi.nlm.nih.gov/27505156","citation_count":20,"is_preprint":false},{"pmid":"27117205","id":"PMC_27117205","title":"Comparison of the radiotoxicity of the 99mTc-labeled compounds 99mTc-pertechnetate, 99mTc-HMPAO and 99mTc-MIBI.","date":"2016","source":"International journal of radiation biology","url":"https://pubmed.ncbi.nlm.nih.gov/27117205","citation_count":19,"is_preprint":false},{"pmid":"11843289","id":"PMC_11843289","title":"Detection of CD55- and/or CD59-deficient red cell populations in patients with plasma cell dyscrasias.","date":"2002","source":"International journal of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/11843289","citation_count":19,"is_preprint":false},{"pmid":"29788264","id":"PMC_29788264","title":"MPK-1/ERK pathway regulates DNA damage response during development through DAF-16/FOXO.","date":"2018","source":"Nucleic 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Factor-1α Regulates CD55 in Airway Epithelium.","date":"2016","source":"American journal of respiratory cell and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/27494303","citation_count":15,"is_preprint":false},{"pmid":"22325826","id":"PMC_22325826","title":"DAF/CD55 and Protectin/CD59 modulate adaptive immunity and disease outcome in experimental autoimmune myasthenia gravis.","date":"2012","source":"Journal of neuroimmunology","url":"https://pubmed.ncbi.nlm.nih.gov/22325826","citation_count":15,"is_preprint":false},{"pmid":"38042929","id":"PMC_38042929","title":"Role of PDGFRA+ cells and a CD55+ PDGFRALo fraction in the gastric mesenchymal niche.","date":"2023","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/38042929","citation_count":14,"is_preprint":false},{"pmid":"20808816","id":"PMC_20808816","title":"Identification of hookworm DAF-16/FOXO response elements and direct gene targets.","date":"2010","source":"PloS 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The third short consensus repeat (SCR3) of DAF is responsible for its complement regulatory activity and signaling.\",\n      \"method\": \"Functional review synthesizing biochemical and molecular cloning data; SCR domain analysis\",\n      \"journal\": \"The Journal of laboratory and clinical medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — molecular cloning combined with domain-level functional analysis, widely replicated across multiple studies in the field\",\n      \"pmids\": [\"7511675\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"CD55 is a GPI-anchored protein associated with tyrosine kinases on the inner leaflet of the plasma membrane, enabling signal transduction despite lacking a transmembrane domain.\",\n      \"method\": \"Biochemical association studies; GPI anchor characterization\",\n      \"journal\": \"The Journal of laboratory and clinical medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — biochemical association data reported in a review, replicated conceptually in subsequent immunoprecipitation studies\",\n      \"pmids\": [\"7511675\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"CD55 co-immunoprecipitates with CD59 and a common 80-kDa glycoprotein from detergent lysates, forming noncovalent membrane complexes. These CD55/CD59/80-kDa complexes contain protein kinase activity, linking GPI-anchored CD55 to intracellular signaling.\",\n      \"method\": \"Co-immunoprecipitation from HPB ALL cell line detergent lysates; identification of protein kinase activity in immune complexes\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single Co-IP/pulldown with kinase activity assay, single lab but two orthogonal methods\",\n      \"pmids\": [\"1715364\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"CD55 (DAF) is the HeLa cell receptor for Enterovirus 70 (EV70). Anti-DAF monoclonal antibodies inhibited EV70 binding to HeLa cells; stable expression of human DAF in murine NIH 3T3 cells conferred EV70 binding and supported virus replication.\",\n      \"method\": \"Monoclonal antibody blocking assay; heterologous expression of human DAF in NIH 3T3 cells; radiolabeled virus binding assay; immunoprecipitation\",\n      \"journal\": \"Journal of virology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution via heterologous expression plus antibody inhibition plus radiolabeled binding, multiple orthogonal methods in one study\",\n      \"pmids\": [\"8764022\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Cardiovirulent Group B Coxsackievirus 3 (CVB3) uses CD55 (DAF) as an attachment receptor. Anti-DAF monoclonal antibodies directed against SCR2 and SCR3 domains most effectively blocked virus binding and infection. Virus binding was reduced by phosphatidylinositol phospholipase C treatment that removes GPI-anchored DAF. Virus binding and internalization were associated with DAF down-regulation at the cell surface.\",\n      \"method\": \"Monoclonal antibody blocking assay; phospholipase C treatment to deplete GPI-anchored DAF; flow cytometry; competitive binding assays\",\n      \"journal\": \"Virology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple orthogonal methods (antibody blocking, enzymatic GPI removal, flow cytometry, competitive binding), identifying SCR2/3 as the binding domain\",\n      \"pmids\": [\"9601501\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"CD55 associates with a specific 43-kDa DAF-associated protein (identified by mAb 2E12-G7) that acts as a signal transducer. Cross-linking of DAF via its associated 43-kDa protein induced tyrosine phosphorylation of proteins of 45, 72, 78 and ~100 kDa in peripheral blood mononuclear cells. This 43-kDa antigen was present in CD55 but not CD59 immunoprecipitates, indicating specific association.\",\n      \"method\": \"Affinity purification of DAF-associated proteins; monoclonal antibody generation; co-immunoprecipitation; surface biotinylation and immunoblotting; tyrosine phosphorylation assay with [gamma-32P]ATP\",\n      \"journal\": \"International immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal immunoprecipitation plus functional phosphorylation assay, single lab\",\n      \"pmids\": [\"9620603\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Mouse DAF (CD55) exists in multiple isoforms generated by alternative splicing, including GPI-anchored and transmembrane forms encoded by separate genes (Daf-GPI and Daf-TM). Stable expression of either TM or GPI-anchored mouse DAF in CHO cells reduced C3b deposition and protected cells from complement-mediated lysis in a cell-lysis assay. Soluble recombinant mouse DAF inhibited complement in a haemolytic assay.\",\n      \"method\": \"Molecular cloning; stable transfection of CHO cells; C3b deposition assay; cell lysis assay; haemolytic assay with soluble recombinant DAF\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution via heterologous expression, functional complement inhibition confirmed by multiple assays in one study\",\n      \"pmids\": [\"10417349\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"CD55 is a specific cellular ligand for the seven-transmembrane receptor CD97, and this receptor-ligand pair is expressed on fibroblast-like synoviocytes (FLS) and macrophages respectively in synovial tissue, suggesting a role in mediating FLS-macrophage interactions and maintaining synovial architecture.\",\n      \"method\": \"Immunohistochemical analysis of synovial biopsy specimens; ELISA for soluble CD97 in synovial fluid\",\n      \"journal\": \"Arthritis and rheumatism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — immunohistochemistry plus ELISA establishing expression pattern; ligand identity for CD97 based on prior published binding data referenced in the paper\",\n      \"pmids\": [\"10211878\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Exosomes derived from antigen-presenting cells express GPI-anchored CD55 and CD59 but not the transmembrane protein CD46. Antibody blockade of CD55 in the presence of sensitizing antibody and human serum resulted in increased C3b deposition and significantly increased exosome lysis, demonstrating that CD55 on exosomes functionally protects them from complement-mediated lysis.\",\n      \"method\": \"Flow cytometry of exosome surface proteins; antibody blocking experiments; C3b deposition assay; lysis assay\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — functional antibody-blocking experiment with defined complement readouts (C3b deposition and lysis), multiple orthogonal measures in one study\",\n      \"pmids\": [\"12645951\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"CD55 (DAF) suppresses adaptive T cell immune responses in vivo. Daf1-/- mice showed significantly enhanced T cell responses to immunization, characterized by hypersecretion of IFN-γ and IL-2 and down-regulation of IL-10. This was complement-dependent: disabling complement in Daf1-/- mice normalized T cell cytokine secretion. CD55 deficiency also exacerbated EAE disease severity, which was also complement-dependent.\",\n      \"method\": \"Daf1 knockout mouse model; active immunization with antigen; in vitro lymphocyte restimulation cytokine assays; EAE model with complement inhibition\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO with defined cellular phenotype, genetic and pharmacologic complement inhibition as epistasis, two disease models, multiple labs' models referenced\",\n      \"pmids\": [\"15710649\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"In nonpolarized HeLa cells, DAF-binding CVB3 entry requires dynamin and lipid rafts but not caveolin, clathrin, or endosomal acidification. Unlike in polarized Caco-2 cells, CVB3 entered HeLa cells with CAR (not DAF-mediated entry). Tyrosine kinase inhibition blocked an early infection event but did not prevent virus entry, indicating DAF-mediated tyrosine kinase signaling is not required for entry into nonpolarized cells.\",\n      \"method\": \"Dominant-negative proteins; siRNA knockdown of endocytic pathway components; pharmacologic inhibitors; immunofluorescence microscopy\",\n      \"journal\": \"Journal of virology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic and pharmacologic perturbations of specific endocytic pathways, single lab\",\n      \"pmids\": [\"19710132\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Deletion of CD55 ameliorates arthritis in collagen-induced and K/BxN serum-transfer mouse models, demonstrating that CD55 interaction with CD97 on infiltrating macrophages plays a pathogenic role in RA beyond its complement-inhibitory function. Similarly, CD97-/- mice had reduced arthritis, consistent with the CD55/CD97 axis driving disease.\",\n      \"method\": \"CD55-/- and CD97-/- mouse models; collagen-induced arthritis; K/BxN serum transfer arthritis model; clinical and immunohistochemical evaluation\",\n      \"journal\": \"Arthritis and rheumatism\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two independent knockout mouse lines in two distinct arthritis models, complementary genetic evidence for CD55/CD97 pathway\",\n      \"pmids\": [\"20131275\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"CD55 produced by fibroblast-like synoviocytes (FLS) is deposited on collagen type I and III reticular fibers in the synovial extracellular matrix; this ECM-associated CD55 is resistant to phospholipase C cleavage and co-localizes with complement C3. CD55 deficiency on a FcγRIIB-null background exaggerated K/BxN-induced arthritis, indicating that ECM-deposited CD55 protects synovial tissue from immune complex-mediated complement attack.\",\n      \"method\": \"Confocal microscopy co-localization; in situ hybridization; flow cytometry; phospholipase C treatment; K/BxN serum transfer arthritis model in CD55/Fcgr2b double-deficient mice; 3D FLS micromass culture\",\n      \"journal\": \"Arthritis research & therapy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (confocal co-localization, enzymatic resistance assay, in vivo genetic model) establishing ECM localization and functional consequence\",\n      \"pmids\": [\"25596646\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Biallelic loss-of-function mutations in CD55 cause loss of CD55 protein expression, leading to increased complement activation on T lymphocytes with surface deposition of complement and generation of soluble C5a, defective CD55-mediated costimulatory function, and defective cytokine modulation. Genetic reconstitution of CD55 or treatment with a complement-inhibitory antibody reversed abnormal complement activation (CHAPLE syndrome).\",\n      \"method\": \"Whole-exome sequencing; functional assays on patients' T lymphocytes (complement deposition, C5a generation); exogenous induction of CD55 expression for genetic reconstitution; complement-inhibitory antibody treatment\",\n      \"journal\": \"The New England journal of medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — loss-of-function human genetics combined with functional reconstitution and pharmacologic rescue, multiple mechanistic readouts\",\n      \"pmids\": [\"28657829\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"In endometrioid cancer, CD55 functions in a complement-independent manner requiring lipid raft localization. CD55 regulates cancer stem cell self-renewal and core pluripotency genes via ROR2/JNK signaling, and in parallel regulates cisplatin resistance via lymphocyte-specific protein tyrosine kinase (LCK) signaling, which induces DNA repair genes. These represent a bifurcating signaling axis downstream of CD55.\",\n      \"method\": \"Comparative CSC vs non-CSC analysis; lipid raft disruption; ROR2/JNK pathway inhibition; LCK inhibitor (saracatinib) treatment; gene expression analysis of pluripotency and DNA repair genes; loss-of-function knockdown\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (lipid raft disruption, kinase pathway inhibition, KD with defined molecular readouts) establishing two parallel signaling axes in one study\",\n      \"pmids\": [\"28838952\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Hepatitis C virus (HCV) infection induces expression of a secreted isoform of CD55 (sCD55) generated by alternative splicing. Conditioned medium from HCV-infected hepatocytes and serum from chronically HCV-infected patients inhibited C3 convertase activity and complement-dependent cytolysis; CD55-blocking antibody inhibited this effect, implicating sCD55 in impairment of complement function.\",\n      \"method\": \"HCV infection/replicon system; RT-PCR for sCD55 splice variant; C3 convertase inhibition assay; complement-dependent cytolysis assay of sheep erythrocytes; antibody blocking\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional complement assays with antibody blocking establishing sCD55's role, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"27357152\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Parainfluenza virus 5 (PIV5) incorporates functional CD55 (and CD46) into virions during assembly. CD55-containing PIV5 virions were highly resistant to complement-mediated neutralization; CD46-containing PIV5 was not. PIV5 infection upregulated cell surface CD55 expression (further enhanced by TNF-α), and virus derived from higher CD55-expressing cells was more complement-resistant in vitro.\",\n      \"method\": \"Virion protein analysis; complement-mediated neutralization assay comparing CD55-incorporating vs non-incorporating virions; flow cytometry of infected cell surface CD55\",\n      \"journal\": \"Virology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional neutralization assay with virions selectively incorporating CD55, single lab\",\n      \"pmids\": [\"27505156\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"HPV E6 protein expression dramatically enriches the CD55+ subpopulation in cervical cancer cells. The CD55+ subpopulation shows enhanced sphere-forming ability, tumourigenicity, cell migration, and radioresistance. CRISPR/Cas9 knockout of CD55 in HPV-E6-overexpressing cells abolished tumourigenic effects of the E6 protein, placing CD55 downstream of E6 in a pathway promoting cervical cancer aggressiveness.\",\n      \"method\": \"CRISPR/Cas9 CD55 knockout; ectopic HPV-E6 expression; flow cytometry of CD55+ subpopulations; sphere formation assay; in vitro and in vivo tumourigenicity assay; radiation treatment assay\",\n      \"journal\": \"The Journal of pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR KO with defined molecular/phenotypic readout epistasis to E6, single lab with multiple assays\",\n      \"pmids\": [\"28944962\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ST3GAL1-mediated O-linked sialylation of CD55 is required for CD55's immune-evasion function in breast cancer. ST3GAL1 silencing shifted the O-glycan profile of CD55 from disialylated core 2 to nonsialylated core 1 structures without affecting N-glycans. O-desialylation of CD55 resulted in increased C3 deposition, increased complement-mediated lysis, and enhanced sensitivity to antibody-dependent cell-mediated cytotoxicity.\",\n      \"method\": \"ST3GAL1 siRNA knockdown; tandem mass spectrometry of N- and O-linked oligosaccharides of CD55; C3 deposition assay; complement-mediated lysis assay; ADCC assay\",\n      \"journal\": \"Cancer immunology research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — detailed glycan structural analysis by mass spectrometry combined with functional complement assays, multiple orthogonal methods in one study\",\n      \"pmids\": [\"33177111\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CD55 on human erythrocytes is specifically required for internalization of Plasmodium falciparum parasites, not for pre-invasion kinetics, erythrocyte deformability, or echinocytosis. CRISPR-Cas9 editing to ablate CD55, antibody-based inhibition, and live cell imaging showed that parasites attached normally to CD55-null erythrocytes but entry was inhibited. CD55 acts after rhoptry discharge and appears to play a role in stability and/or progression of the moving junction.\",\n      \"method\": \"CRISPR-Cas9 editing of erythrocyte CD55; antibody-based inhibition; live cell imaging; deformability and echinocytosis assays\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — genetic ablation plus antibody inhibition plus live imaging, multiple orthogonal methods identifying specific step of invasion\",\n      \"pmids\": [\"34028351\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CD55 is a transcriptional target of HIF-2α in neuroblastoma cells. HIF-2α expression is sufficient to sustain stem-like features, while CD55 protein specifically contributes to colony growth and cell invasion but not stemness. CD55-positive populations display pro-invading and anti-adhesive properties.\",\n      \"method\": \"HIF-2α gain-of-function; CD55 functional characterization in CD55-positive vs CD55-negative subpopulations; colony formation and invasion assays\",\n      \"journal\": \"Oncogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — functional characterization of CD55-positive cells with separation of invasion from stemness, single lab\",\n      \"pmids\": [\"27043658\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"HIF-1α negatively regulates CD55 expression in airway epithelial cells. Hypoxia down-regulated CD55 on small-airway epithelial cells in vitro and in murine lungs in vivo, associated with local complement activation. Pharmacologic inhibition or siRNA silencing of HIF-1α during hypoxia recovered CD55 expression; HIF-1α overexpression down-regulated CD55.\",\n      \"method\": \"Pharmacologic HIF-1α inhibition; HIF-1α gene silencing; HIF-1α overexpression; in vivo murine hypoxia model; complement activation assay\",\n      \"journal\": \"American journal of respiratory cell and molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — bidirectional manipulation (inhibition and overexpression) of HIF-1α both in vitro and in vivo with defined CD55 and complement outcome measures\",\n      \"pmids\": [\"27494303\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"EGFR/Wnt signaling induces β-catenin-mediated lncRNA LINC00973 expression, which sponges miR-216b (targeting CD55) and miR-150 (targeting CD59), resulting in upregulated CD55/CD59 that suppresses the complement system and CD8+ T cell activation. CD55/CD59-neutralizing antibody treatment or LINC00973 promoter mutation activated complement and CD8+ T cells and inhibited tumor growth; combined anti-CD55/CD59 and anti-PD-1 treatment showed synergistic tumor-inhibiting effects.\",\n      \"method\": \"EGFR/Wnt/β-catenin pathway manipulation; LINC00973 promoter mutation; miRNA sponging mechanism validation; complement activation assay; CD8+ T cell activation assay; antibody neutralization; anti-PD-1 combination therapy in vivo\",\n      \"journal\": \"Nature cancer\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple genetic perturbations of upstream pathway with mechanistic miRNA sponge mechanism plus functional complement and immune readouts, in vitro and in vivo\",\n      \"pmids\": [\"36271172\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Bee venom upregulates CD55 mRNA and protein in THP-1 cells via ERK phosphorylation. CD55 induction by bee venom inactivates complement as measured by C3 convertase activity. In an AD mouse model, CD55 was decreased and C3C/MAC were elevated; bee venom treatment reversed these changes and alleviated AD symptoms.\",\n      \"method\": \"mRNA/protein expression analysis; ERK phosphorylation assay; complement-dependent cytotoxicity assay; bacteria-killing assay; in vivo AD mouse model with bee venom treatment\",\n      \"journal\": \"Toxins\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — ERK-CD55 signaling link with functional complement readout, single lab with in vitro and in vivo evidence\",\n      \"pmids\": [\"31027358\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"CD55 (DAF) promotes CD1d expression on macrophages during CVB3 H3 infection and is required for activation of Vγ4+ T cells that mediate myocarditis. DAF-/- mice showed reduced CD1d expression and few Vγ4+IFNγ+ cells; the immunopathogenic mechanism differs in DAF-/- animals (CD8+ T cell depletion aggravates rather than protects disease), establishing CD55 as required for the CD1d/Vγ4+ T cell pathway of CVB3-induced myocarditis.\",\n      \"method\": \"DAF-/- mouse infection model; CD1d expression analysis; Vγ4+ T cell depletion; CD8+ T cell depletion; IFN-γ intracellular staining\",\n      \"journal\": \"Viral immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO model with mechanistic T-cell depletion epistasis experiments, single lab\",\n      \"pmids\": [\"16817758\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"VEGF upregulates CD55 expression at the cell surface and within the extracellular matrix of endothelial cells (HUVEC). MMP-7 releases intact, functionally active CD55 from ECM, whereas papain degrades it and collagenase fails to release it, establishing that metalloproteinase-mediated shedding generates soluble functional CD55 in the tumor environment.\",\n      \"method\": \"VEGF stimulation of HUVEC; flow cytometry; ECM CD55 quantification; complement functional assay; protease treatment (papain, collagenase, MMP-7) of ECM-bound CD55\",\n      \"journal\": \"Tissue antigens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional complement assay confirming activity of released CD55 combined with specific protease release experiments, single lab\",\n      \"pmids\": [\"12445304\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CD55 (DAF) is a GPI-anchored complement regulator that accelerates decay of C3 and C5 convertases primarily through its third short consensus repeat (SCR3), protecting host cells, exosomes, and ECM from complement-mediated attack; beyond complement regulation, CD55 serves as a receptor for multiple enteroviruses (EV70, CVB3) and the malaria parasite (mediating P. falciparum internalization at the moving junction), acts as a ligand for the adhesion receptor CD97 to modulate cell–cell interactions and inflammatory responses, transduces intracellular signals via associated tyrosine kinases and downstream ROR2/JNK and LCK pathways to drive cancer stem cell self-renewal and chemoresistance, and has its expression regulated transcriptionally by HIF-1α/HIF-2α and post-translationally by ST3GAL1-mediated O-linked sialylation, which controls its complement-inhibitory efficacy in tumors.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CD55 (DAF) is a GPI-anchored cell-surface glycoprotein whose core function is regulation of the complement cascade, accelerating decay of C3/C5 convertases to protect host cells from complement-mediated attack, an activity localized to its third short consensus repeat (SCR3) [#0, #6]. This protective coat operates not only on cells but also on antigen-presenting-cell exosomes and, in a phospholipase-C-resistant ECM-deposited form on collagen fibers, on synovial tissue, shielding these compartments from C3b deposition and lysis [#8, #12]. Biallelic loss-of-function mutations in CD55 cause CHAPLE syndrome, a human disease of unchecked complement activation on T lymphocytes with C5a generation that is reversed by genetic reconstitution or complement-inhibitory antibody [#13]. Beyond complement, CD55 transduces intracellular signals despite lacking a transmembrane domain by associating with plasma-membrane tyrosine kinases and a 43-kDa signal-transducing partner, driving tyrosine phosphorylation cascades [#1, #2, #5]; in cancer this manifests as complement-independent, lipid-raft-dependent signaling through ROR2/JNK to sustain cancer stem cell self-renewal and through LCK to confer chemoresistance [#14]. CD55 also serves as a cellular receptor for Enterovirus 70 and Coxsackievirus B3 (via SCR2/SCR3) and is specifically required for Plasmodium falciparum erythrocyte internalization at the moving junction [#3, #4, #19], and acts as the ligand for the adhesion GPCR CD97, an interaction that drives macrophage-mediated arthritis pathology [#7, #11]. CD55 expression and complement-inhibitory efficacy are tightly regulated: transcriptionally by HIF-1\\u03b1 (repressive) and HIF-2\\u03b1 (inductive) under hypoxia and by an EGFR/Wnt/\\u03b2-catenin\\u2013LINC00973 axis, and post-translationally by ST3GAL1-mediated O-sialylation that controls its tumor immune-evasion capacity [#21, #20, #22]. In vivo, CD55 restrains adaptive T cell responses in a complement-dependent manner [#9].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Established the foundational function of CD55 as a complement regulator and mapped the activity to a defined structural module, answering where in the protein complement inhibition resides.\",\n      \"evidence\": \"Functional review synthesizing molecular cloning and SCR domain analysis localizing activity to SCR3\",\n      \"pmids\": [\"7511675\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic-level mechanism of convertase decay acceleration not resolved here\", \"Relative contributions of SCR2 vs SCR3 to different ligand interactions not delineated\"]\n    },\n    {\n      \"year\": 1991,\n      \"claim\": \"Addressed how a GPI-anchored protein lacking a cytoplasmic tail could signal, by showing CD55 forms noncovalent membrane complexes with CD59 and an 80-kDa glycoprotein carrying protein kinase activity.\",\n      \"evidence\": \"Co-immunoprecipitation from HPB ALL detergent lysates with kinase activity assay\",\n      \"pmids\": [\"1715364\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Identity of the 80-kDa glycoprotein and kinase not defined\", \"Single cell line, single lab\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Refined the signaling model by identifying a specific 43-kDa DAF-associated transducer whose cross-linking elicits a defined tyrosine phosphorylation cascade.\",\n      \"evidence\": \"Affinity purification, reciprocal co-immunoprecipitation, and tyrosine phosphorylation assay in PBMCs\",\n      \"pmids\": [\"9620603\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular identity of the 43-kDa protein unestablished\", \"Downstream physiologic consequence of the phosphorylation events unclear\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Demonstrated CD55 is a bona fide viral receptor by reconstituting EV70 binding and replication in heterologous murine cells, opening a non-complement role for the protein.\",\n      \"evidence\": \"Anti-DAF antibody blocking, heterologous expression in NIH 3T3, radiolabeled virus binding\",\n      \"pmids\": [\"8764022\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CD55 alone suffices for entry vs requires co-receptors not addressed\", \"Binding domain not mapped in this study\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Extended viral receptor use to CVB3 and mapped the binding determinant to SCR2/SCR3, linking the receptor surface to specific structural repeats.\",\n      \"evidence\": \"Domain-specific antibody blocking, PI-PLC GPI removal, flow cytometry, competitive binding\",\n      \"pmids\": [\"9601501\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Overlap between virus-binding and complement-regulatory surfaces not fully separated\", \"Internalization mechanism not defined here\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Confirmed by gain-of-function reconstitution that CD55, in both GPI and transmembrane isoforms, is sufficient to inhibit complement and protect cells from lysis.\",\n      \"evidence\": \"Cloning and stable CHO expression with C3b deposition, cell lysis, and hemolytic assays\",\n      \"pmids\": [\"10417349\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional differences between TM and GPI isoforms in vivo not resolved\", \"Mouse-human isoform divergence may limit translation\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Identified CD55 as the ligand for the seven-transmembrane receptor CD97 and placed this pair in synovial tissue, suggesting a complement-independent adhesion/inflammation role.\",\n      \"evidence\": \"Immunohistochemistry of synovium and ELISA for soluble CD97\",\n      \"pmids\": [\"10211878\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct functional consequence of CD55-CD97 binding not tested here\", \"Binding affinity and stoichiometry not measured\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Showed CD55's protective function extends beyond cells to APC-derived exosomes, broadening the substrate range of complement regulation.\",\n      \"evidence\": \"Flow cytometry of exosome surface proteins with antibody blocking, C3b deposition and lysis assays\",\n      \"pmids\": [\"12645951\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance of exosomal CD55 protection not established\", \"Mechanism of CD55 sorting onto exosomes unknown\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Established a physiologic immunoregulatory role by showing CD55 restrains adaptive T cell cytokine responses in a complement-dependent manner.\",\n      \"evidence\": \"Daf1-/- mice with immunization, cytokine restimulation assays, and EAE model with complement disabling\",\n      \"pmids\": [\"15710649\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cellular target (T cell intrinsic vs APC) of complement effect not fully separated\", \"Human relevance inferred from mouse\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Revealed a complement-independent immunopathogenic role, showing CD55 is required for the CD1d/Vγ4+ T cell pathway driving CVB3 myocarditis.\",\n      \"evidence\": \"DAF-/- infection model with CD1d analysis and T cell subset depletions\",\n      \"pmids\": [\"16817758\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular link between CD55 and CD1d induction unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Defined how soluble, functionally active CD55 is generated in tissue by showing VEGF induces ECM CD55 and MMP-7 specifically releases it intact.\",\n      \"evidence\": \"VEGF stimulation of HUVEC, ECM quantification, complement assay, protease release experiments\",\n      \"pmids\": [\"12445304\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo contribution of MMP-7-released CD55 to tumor complement evasion not shown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Demonstrated genetically that the CD55-CD97 axis drives arthritis pathology independent of complement, validating the receptor-ligand interaction functionally.\",\n      \"evidence\": \"CD55-/- and CD97-/- mice in collagen-induced and K/BxN serum-transfer arthritis models\",\n      \"pmids\": [\"20131275\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream macrophage signaling from CD97 engagement not detailed\", \"Relative weight of adhesion vs complement roles not quantified\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Showed FLS-produced CD55 is deposited on synovial ECM collagen in a PI-PLC-resistant form that protects tissue from immune-complex-driven complement attack.\",\n      \"evidence\": \"Confocal co-localization, in situ hybridization, PLC resistance assay, K/BxN arthritis in CD55/Fcgr2b double-deficient mice\",\n      \"pmids\": [\"25596646\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism anchoring CD55 to collagen unknown\", \"Whether ECM CD55 also engages CD97 not addressed\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defined CD55 as a human disease gene, establishing CHAPLE syndrome as a complement dysregulation disorder caused by CD55 loss and reversible by complement inhibition.\",\n      \"evidence\": \"Whole-exome sequencing, patient T lymphocyte functional assays, genetic reconstitution and antibody rescue\",\n      \"pmids\": [\"28657829\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of CD55's costimulatory function distinct from complement decay not resolved\", \"Genotype-phenotype variability not detailed\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Uncovered a complement-independent, lipid-raft-dependent signaling output of CD55 that bifurcates into ROR2/JNK-driven stemness and LCK-driven chemoresistance in cancer.\",\n      \"evidence\": \"Lipid raft disruption, ROR2/JNK and LCK pathway inhibition, knockdown with pluripotency and DNA-repair gene readouts\",\n      \"pmids\": [\"28838952\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How CD55 physically activates ROR2 and LCK at the raft is unknown\", \"Generality across tumor types beyond endometrioid not established\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Placed CD55 downstream of an oncogenic driver, showing HPV-E6 enriches a tumourigenic CD55+ cell population that requires CD55 for its aggressive phenotype.\",\n      \"evidence\": \"CRISPR/Cas9 CD55 knockout, ectopic E6 expression, sphere/tumourigenicity/radioresistance assays\",\n      \"pmids\": [\"28944962\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which E6 enriches CD55+ cells unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Showed transcriptional control of CD55 by hypoxia factors, with HIF-1α repressing CD55 in airway epithelium to permit local complement activation.\",\n      \"evidence\": \"Bidirectional HIF-1α manipulation in vitro and in vivo murine hypoxia with complement readouts\",\n      \"pmids\": [\"27494303\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct vs indirect promoter regulation by HIF-1α not dissected\", \"Tissue specificity of repression vs induction unexplained\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Demonstrated HIF-2α drives CD55 expression in neuroblastoma and that CD55 contributes specifically to invasion and colony growth rather than stemness, separating CD55's roles from the HIF-2α stemness program.\",\n      \"evidence\": \"HIF-2α gain-of-function and functional comparison of CD55-positive vs negative subpopulations\",\n      \"pmids\": [\"27043658\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Apparent opposite-direction HIF regulation vs airway epithelium unreconciled\", \"Single lab\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Showed pathogens exploit CD55 for complement evasion, with HCV inducing a secreted CD55 splice isoform that inhibits C3 convertase systemically.\",\n      \"evidence\": \"HCV replicon system, RT-PCR splice detection, C3 convertase and cytolysis assays with antibody blocking\",\n      \"pmids\": [\"27357152\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cellular source of patient serum sCD55 not pinpointed\", \"Single lab\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Showed enveloped viruses physically incorporate functional CD55 into virions to resist complement neutralization, a host-protein-hijacking evasion mechanism.\",\n      \"evidence\": \"Virion protein analysis and complement neutralization comparing CD55-incorporating vs non-incorporating PIV5\",\n      \"pmids\": [\"27505156\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of selective CD55 vs CD46 incorporation unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Established that O-linked sialylation by ST3GAL1 is required for CD55's complement-inhibitory immune-evasion function, defining a post-translational control point.\",\n      \"evidence\": \"ST3GAL1 knockdown, mass spectrometry of CD55 glycans, C3 deposition, lysis, and ADCC assays\",\n      \"pmids\": [\"33177111\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for how sialic acid affects convertase decay unknown\", \"Generality beyond breast cancer not tested\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Pinpointed the precise step of malaria invasion requiring CD55, showing it acts after rhoptry discharge in moving junction stability rather than in attachment.\",\n      \"evidence\": \"CRISPR-Cas9 erythrocyte CD55 ablation, antibody inhibition, live cell imaging, deformability/echinocytosis controls\",\n      \"pmids\": [\"34028351\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct parasite ligand for CD55 at the junction not identified\", \"Molecular basis of junction stabilization unresolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined an oncogenic non-coding RNA circuit that upregulates CD55 to suppress complement and CD8+ T cells, and showed therapeutic synergy of CD55 blockade with checkpoint inhibition.\",\n      \"evidence\": \"EGFR/Wnt/β-catenin manipulation, LINC00973 promoter mutation, miRNA sponge validation, complement and T cell assays, anti-PD-1 combination in vivo\",\n      \"pmids\": [\"36271172\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contribution of CD55 vs CD59 to the immune suppression not separated\", \"Clinical translatability of combination therapy untested\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Linked an ERK-dependent stimulus to CD55 induction and complement inactivation, with bee venom restoring CD55 and ameliorating an inflammatory disease model.\",\n      \"evidence\": \"Expression and ERK phosphorylation assays in THP-1, complement assays, AD mouse model\",\n      \"pmids\": [\"31027358\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct transcriptional effector downstream of ERK not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular identities of the CD55-associated kinases/transducers (80-kDa and 43-kDa partners) and the structural basis by which raft localization couples CD55 to ROR2/JNK and LCK signaling remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"80-kDa and 43-kDa associated proteins remain molecularly unidentified\", \"No structural model linking CD55 ectodomain engagement to intracellular kinase activation\", \"Mechanism of CD55-CD97 signal transduction into macrophages undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 6, 13]},\n      {\"term_id\": \"GO:0001618\", \"supporting_discovery_ids\": [3, 4, 19]},\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [7, 11]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [1, 2, 5, 14]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 4, 6]},\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [12, 25]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [0, 8, 9, 13, 22]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [13, 17, 22]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 5, 14]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"CD59\", \"CD97\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}