{"gene":"PVRIG","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":2016,"finding":"CD112R (PVRIG) is a coinhibitory receptor expressed preferentially on T cells that inhibits TCR-mediated signals; its ligand is CD112 (PVRL2/Nectin-2), which is widely expressed on antigen-presenting cells and tumor cells, and CD112R competes with CD226 for CD112 binding. Disrupting the CD112R-CD112 interaction enhances human T cell response.","method":"Receptor-ligand binding assays, T cell functional assays (TCR-mediated signaling readouts), competition binding with CD226, blockade experiments","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal binding assays, functional T cell assays, competition binding, independently replicated in subsequent studies","pmids":["26755705"],"is_preprint":false},{"year":2017,"finding":"CD112R (PVRIG) is expressed on human NK cells, and blockade of CD112R (separately or in combination with TIGIT) enhances NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) triggered by trastuzumab. TIGIT (but not CD112R) is preferentially expressed on CD16+ NK cell subset and is upregulated upon NK cell activation via ADCC.","method":"Flow cytometry, NK cell functional assays (ADCC, cytotoxicity), antibody blockade of CD112R and TIGIT","journal":"Cancer immunology, immunotherapy : CII","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional NK cell assays with blockade, single lab, multiple readouts","pmids":["28623459"],"is_preprint":false},{"year":2019,"finding":"PVRIG antagonism increases CD8+ T cell cytokine production and cytotoxic activity. The inhibitory effect of PVRL2 on T cells is mediated specifically by PVRIG and not TIGIT, establishing PVRIG-PVRL2 as a nonredundant signaling node distinct from TIGIT-PVR. Combined PVRIG and TIGIT or PD-1 blockade further increases T cell activation.","method":"Antibody blockade of PVRIG, TIGIT, and PD-1; CD8+ T cell cytokine production assays; cytotoxicity assays; tumor-infiltrating lymphocyte (TIL) functional assays","journal":"Cancer immunology research","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal functional assays (cytokine, cytotoxicity, TIL), nonredundancy demonstrated by selective pathway blockade, replicated across conditions","pmids":["30659054"],"is_preprint":false},{"year":2019,"finding":"Murine PVRIG binds PVRL2 strongly (principal ligand) and interacts weakly with PVR. PVRIG-deficient mouse CD8+ T cells mount a stronger antigen-specific effector response during acute Listeria monocytogenes infection. In the tumor microenvironment, infiltrating CD8+ T cells express PVRIG while its ligand PVRL2 is detected predominantly on myeloid cells and tumor cells.","method":"PVRIG knockout mice, Listeria infection model, tumor growth assays in PVRIG-/- vs. wild-type mice, flow cytometry for receptor/ligand expression, binding assays","journal":"Cancer immunology research","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO with defined phenotypic readout, binding assay for ligand selectivity, in vivo tumor models, multiple orthogonal methods","pmids":["30659055"],"is_preprint":false},{"year":2021,"finding":"PVRIG blockade in NK cells slows tumor growth in murine models and prolongs survival by inhibiting NK cell exhaustion as well as CD8+ T cell exhaustion. In Rag1-/- mice (lacking adaptive immunity), PVRIG blockade still provided therapeutic effect, demonstrating a T cell-independent NK-cell-mediated mechanism. NK cells are required for anti-tumor efficacy of PVRIG blockade.","method":"PVRIG-deficient mice, Rag1-/- mice, NK/CD8+ T cell depletion in vivo, syngeneic and xenograft tumor models, NK cell functional assays","journal":"Journal of hematology & oncology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO, cell depletion experiments, Rag1-/- immunodeficient model, multiple tumor models establishing NK cell-intrinsic mechanism","pmids":["34174928"],"is_preprint":false},{"year":2021,"finding":"NK cell activation (via tumor cell recognition, cytokines IL-2/IL-12, or activating receptor stimulation via CD16 and NKp46) causes reduced PVRIG surface expression. PVRIG is present at higher levels in the cytoplasm than on the cell surface (especially in CD56bright NK cells), and is continually transported to the cell surface via the ER and Golgi in both unstimulated and activated NK cells.","method":"Flow cytometry for surface vs. cytoplasmic PVRIG, ER/Golgi trafficking inhibitors, NK cell activation assays, immunofluorescence","journal":"Haematologica","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization experiments (cytoplasmic vs. surface), trafficking pathway determination, multiple activation stimuli tested, single lab","pmids":["33147937"],"is_preprint":false},{"year":2024,"finding":"Crystal structure of PVRIG in complex with Nectin-2 (PVRL2) reveals that PVRIG possesses a unique CC' loop that complements a double-lock-and-key binding mode contributing to its high affinity for Nectin-2. Charged residues in the F-strands determine ligand selectivity of PVRIG for Nectin-2 but not Necl-5 (CD155/PVR).","method":"X-ray crystallography (crystal structure of PVRIG–Nectin-2 complex), binding affinity comparisons across co-receptors and ligands","journal":"Structure (London, England : 1993)","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with functional validation of binding mode and selectivity determinants, single rigorous study with structural and binding data","pmids":["38626767"],"is_preprint":false},{"year":2024,"finding":"An anti-PVRIG antibody with Fc-competent function (IBI352g4a) binds the extracellular domain of human PVRIG with high affinity (Kd = 0.53 nM) and fully blocks PVRIG-PVRL2 interaction. In vitro, it significantly induces NK cell activation and degranulation but has minimal effect on T cell activation. In vivo, both NK and T cells contribute to antitumor effect, but NK cells play predominant roles; Fc effector function is critical for both NK cell activation and treatment efficacy.","method":"Binding affinity assay (SPR/ELISA), in vitro NK and T cell functional assays, in vivo tumor models with NK/T cell depletion, Fc-effector-function analysis","journal":"Cancer immunology, immunotherapy : CII","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — binding assay, in vitro functional assays, in vivo depletion experiments, single lab, multiple methods","pmids":["38554184"],"is_preprint":false},{"year":2024,"finding":"PVRL2 (CD112) suppresses antitumor immunity through mechanisms beyond PVRIG: deletion of PVRL2 in syngeneic tumor models dramatically reduced tumor growth even in the absence of PVRIG. PVRIG loss showed no additive effect in the absence of PVRL2, placing PVRIG downstream of or dependent on PVRL2 in this pathway. PVRL2 suppresses CD8+ T and NK cells in the tumor microenvironment.","method":"PVRL2 gene deletion in syngeneic mouse tumor models, PVRIG KO mice, combinatorial KO epistasis analysis, immune cell depletion","journal":"Cancer immunology research","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with double KO models, multiple syngeneic tumor models, defines pathway hierarchy between PVRIG and PVRL2","pmids":["38588410"],"is_preprint":false}],"current_model":"PVRIG (CD112R) is a coinhibitory immune checkpoint receptor expressed on T cells and NK cells that binds PVRL2 (Nectin-2/CD112) with high affinity via a unique CC' loop and charged F-strand residues (crystal structure resolved), competing with the costimulatory receptor CD226; engagement of PVRIG by PVRL2 inhibits TCR-mediated T cell signaling and NK cell activation, constituting a nonredundant inhibitory axis distinct from TIGIT-PVR, with PVRIG trafficking continuously from the ER/Golgi to the cell surface and being downregulated upon NK cell activation, and its blockade (alone or in combination with TIGIT or PD-1 blockade) enhancing CD8+ T cell effector function and NK cell cytotoxicity to suppress tumor growth in vivo."},"narrative":{"mechanistic_narrative":"PVRIG (CD112R) is a coinhibitory immune checkpoint receptor expressed on T cells and NK cells that restrains antitumor immunity by engaging the nectin ligand PVRL2 (CD112/Nectin-2) [PMID:26755705, PMID:30659055]. On T cells, PVRIG binds PVRL2 and competes with the costimulatory receptor CD226 for ligand, and its engagement dampens TCR-mediated signaling; disrupting the PVRIG-PVRL2 interaction enhances CD8+ T cell cytokine production and cytotoxicity [PMID:26755705, PMID:30659054]. The PVRIG-PVRL2 axis is nonredundant with the TIGIT-PVR axis, with PVRL2-mediated T cell inhibition transmitted specifically through PVRIG rather than TIGIT, such that combined PVRIG, TIGIT, or PD-1 blockade gives additive activation [PMID:30659054]. Structurally, PVRIG achieves high-affinity, selective recognition of Nectin-2 through a unique CC' loop that supports a double-lock-and-key binding mode and charged F-strand residues that discriminate Nectin-2 from CD155/PVR [PMID:38626767]. On NK cells, PVRIG blockade enhances ADCC and cytotoxicity and reverses NK cell exhaustion, and genetic and depletion studies establish an NK-cell-intrinsic, T cell-independent antitumor mechanism [PMID:28623459, PMID:34174928]. Surface PVRIG is downregulated upon NK cell activation while the protein is continuously trafficked from the ER and Golgi to the cell surface, with a larger cytoplasmic than surface pool [PMID:33147937]. Epistasis analysis places PVRIG within the broader immunosuppressive activity of PVRL2, as PVRL2 deletion suppresses tumor growth even without PVRIG and PVRIG loss confers no further benefit in the absence of PVRL2 [PMID:38588410].","teleology":[{"year":2016,"claim":"Established PVRIG as a coinhibitory receptor on T cells, identifying its ligand and its competition with the activating receptor CD226 — defining the molecular basis of a new inhibitory axis.","evidence":"Receptor-ligand and competition binding assays with CD226, plus TCR-signaling functional readouts in human T cells","pmids":["26755705"],"confidence":"High","gaps":["Downstream signaling motifs transmitting the inhibitory signal not defined","Did not resolve relative contributions of PVRIG vs. CD226 in physiological settings"]},{"year":2017,"claim":"Extended PVRIG function to NK cells, showing blockade augments antibody-dependent cytotoxicity and distinguishing its expression pattern from TIGIT.","evidence":"Flow cytometry and NK cell ADCC/cytotoxicity assays with PVRIG and TIGIT antibody blockade","pmids":["28623459"],"confidence":"Medium","gaps":["Single-lab functional data","Mechanism of NK inhibition not dissected at signaling level"]},{"year":2019,"claim":"Demonstrated that PVRL2-mediated inhibition of CD8+ T cells runs specifically through PVRIG and not TIGIT, establishing PVRIG-PVRL2 as a nonredundant node combinable with TIGIT and PD-1 blockade.","evidence":"Selective antibody blockade of PVRIG/TIGIT/PD-1 with CD8+ T cell cytokine, cytotoxicity, and TIL functional assays","pmids":["30659054"],"confidence":"High","gaps":["Did not establish ligand selectivity at structural level","Combination synergy mechanism not mapped"]},{"year":2019,"claim":"Genetic knockout confirmed PVRIG as a bona fide inhibitory receptor in vivo, with PVRL2 as principal ligand and weak PVR binding, and defined the receptor/ligand cellular compartments in the tumor microenvironment.","evidence":"PVRIG knockout mice, Listeria infection and tumor models, binding assays, flow cytometry for receptor/ligand expression","pmids":["30659055"],"confidence":"High","gaps":["Functional consequence of weak PVR interaction unresolved","Cell-intrinsic signaling output not characterized"]},{"year":2021,"claim":"Resolved whether PVRIG blockade efficacy depends on adaptive immunity by showing an NK-cell-intrinsic, T-cell-independent antitumor mechanism that reverses NK and CD8+ T cell exhaustion.","evidence":"PVRIG-deficient and Rag1-/- mice with NK/CD8 depletion across syngeneic and xenograft tumor models","pmids":["34174928"],"confidence":"High","gaps":["Molecular basis of exhaustion reversal not defined","Relative NK vs. T contribution context-dependent"]},{"year":2021,"claim":"Defined PVRIG subcellular dynamics, showing a predominantly cytoplasmic pool, continuous ER/Golgi-to-surface trafficking, and surface downregulation upon NK activation.","evidence":"Surface vs. cytoplasmic flow cytometry, trafficking inhibitors, immunofluorescence, multiple NK activation stimuli","pmids":["33147937"],"confidence":"Medium","gaps":["Trafficking regulatory machinery unidentified","Functional consequence of activation-induced downregulation unclear","Single lab"]},{"year":2024,"claim":"Crystal structure of the PVRIG-Nectin-2 complex defined the structural determinants of high-affinity binding and ligand selectivity.","evidence":"X-ray crystallography of PVRIG-Nectin-2 complex with binding affinity comparisons across co-receptors and ligands","pmids":["38626767"],"confidence":"High","gaps":["Structure does not address intracellular signaling","Apo PVRIG conformation and competitive interface with CD226 not co-resolved"]},{"year":2024,"claim":"Tested a therapeutic Fc-competent anti-PVRIG antibody, showing blockade preferentially drives NK cell activation and that Fc effector function is critical for efficacy.","evidence":"SPR/ELISA binding (Kd 0.53 nM), in vitro NK and T cell assays, in vivo tumor models with depletion and Fc-effector analysis","pmids":["38554184"],"confidence":"Medium","gaps":["Single-lab antibody-specific findings","Mechanistic basis for NK-over-T selectivity not resolved"]},{"year":2024,"claim":"Genetic epistasis placed PVRIG within the broader immunosuppressive activity of PVRL2, showing PVRL2 acts through PVRIG-independent routes and PVRIG loss adds nothing without PVRL2.","evidence":"PVRL2 and PVRIG single and double knockout syngeneic tumor models with immune cell depletion","pmids":["38588410"],"confidence":"High","gaps":["Identity of additional PVRL2 receptors mediating PVRIG-independent suppression not defined","Pathway hierarchy in human disease not validated"]},{"year":null,"claim":"The intracellular signaling cascade by which PVRIG transmits its inhibitory signal upon PVRL2 engagement remains uncharacterized in the available corpus.","evidence":"","pmids":[],"confidence":"High","gaps":["No cytoplasmic-domain signaling motifs or downstream effectors identified","Mechanism of CD226 antagonism at the signaling level unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0,2,3]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,2]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[5]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[5]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[5]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[0,2,3,4]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,2]}],"complexes":[],"partners":["PVRL2","CD226","TIGIT"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q6DKI7","full_name":"Transmembrane protein PVRIG","aliases":["CD112 receptor","CD112R","Poliovirus receptor-related immunoglobulin domain-containing protein"],"length_aa":326,"mass_kda":34.3,"function":"Cell surface receptor for NECTIN2. May act as a coinhibitory receptor that suppresses T-cell receptor-mediated signals. Following interaction with NECTIN2, inhibits T-cell proliferation. Competes with CD226 for NECTIN2-binding","subcellular_location":"Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q6DKI7/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PVRIG","classification":"Not Classified","n_dependent_lines":20,"n_total_lines":1208,"dependency_fraction":0.016556291390728478},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/PVRIG","total_profiled":1310},"omim":[{"mim_id":"617012","title":"POLIOVIRUS RECEPTOR-RELATED IMMUNOGLOBULIN DOMAIN-CONTAINING PROTEIN; PVRIG","url":"https://www.omim.org/entry/617012"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"lymphoid tissue","ntpm":44.5}],"url":"https://www.proteinatlas.org/search/PVRIG"},"hgnc":{"alias_symbol":["MGC2463","C7orf15","CD112R"],"prev_symbol":[]},"alphafold":{"accession":"Q6DKI7","domains":[{"cath_id":"2.60.40.10","chopping":"44-153","consensus_level":"high","plddt":82.8835,"start":44,"end":153}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6DKI7","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q6DKI7-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q6DKI7-F1-predicted_aligned_error_v6.png","plddt_mean":60.84},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PVRIG","jax_strain_url":"https://www.jax.org/strain/search?query=PVRIG"},"sequence":{"accession":"Q6DKI7","fasta_url":"https://rest.uniprot.org/uniprotkb/Q6DKI7.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q6DKI7/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6DKI7"}},"corpus_meta":[{"pmid":"26755705","id":"PMC_26755705","title":"Identification of CD112R as a novel checkpoint for human T cells.","date":"2016","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/26755705","citation_count":176,"is_preprint":false},{"pmid":"31234588","id":"PMC_31234588","title":"DNAM-1 and the TIGIT/PVRIG/TACTILE Axis: Novel Immune Checkpoints for Natural Killer Cell-Based Cancer Immunotherapy.","date":"2019","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/31234588","citation_count":175,"is_preprint":false},{"pmid":"30659054","id":"PMC_30659054","title":"PVRIG and PVRL2 Are Induced in Cancer and Inhibit CD8+ T-cell Function.","date":"2019","source":"Cancer immunology research","url":"https://pubmed.ncbi.nlm.nih.gov/30659054","citation_count":134,"is_preprint":false},{"pmid":"28623459","id":"PMC_28623459","title":"Blockade of CD112R and TIGIT signaling sensitizes human natural killer cell functions.","date":"2017","source":"Cancer immunology, immunotherapy : CII","url":"https://pubmed.ncbi.nlm.nih.gov/28623459","citation_count":125,"is_preprint":false},{"pmid":"30659055","id":"PMC_30659055","title":"Mouse PVRIG Has CD8+ T Cell-Specific Coinhibitory Functions and Dampens Antitumor Immunity.","date":"2019","source":"Cancer immunology research","url":"https://pubmed.ncbi.nlm.nih.gov/30659055","citation_count":47,"is_preprint":false},{"pmid":"34507594","id":"PMC_34507594","title":"The CD112R/CD112 axis: a breakthrough in cancer immunotherapy.","date":"2021","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/34507594","citation_count":47,"is_preprint":false},{"pmid":"33298247","id":"PMC_33298247","title":"Hitting the complexity of the TIGIT-CD96-CD112R-CD226 axis for next-generation cancer immunotherapy.","date":"2021","source":"BMB reports","url":"https://pubmed.ncbi.nlm.nih.gov/33298247","citation_count":44,"is_preprint":false},{"pmid":"34174928","id":"PMC_34174928","title":"Blockade of checkpoint receptor PVRIG unleashes anti-tumor immunity of NK cells in murine and human solid tumors.","date":"2021","source":"Journal of hematology & oncology","url":"https://pubmed.ncbi.nlm.nih.gov/34174928","citation_count":44,"is_preprint":false},{"pmid":"33903974","id":"PMC_33903974","title":"COM902, a novel therapeutic antibody targeting TIGIT augments anti-tumor T cell function in combination with PVRIG or PD-1 pathway blockade.","date":"2021","source":"Cancer immunology, immunotherapy : CII","url":"https://pubmed.ncbi.nlm.nih.gov/33903974","citation_count":34,"is_preprint":false},{"pmid":"33147937","id":"PMC_33147937","title":"PVRIG is a novel natural killer cell immune checkpoint receptor in acute myeloid leukemia.","date":"2021","source":"Haematologica","url":"https://pubmed.ncbi.nlm.nih.gov/33147937","citation_count":26,"is_preprint":false},{"pmid":"38588410","id":"PMC_38588410","title":"PVRL2 Suppresses Antitumor Immunity through PVRIG- and TIGIT-independent Pathways.","date":"2024","source":"Cancer immunology research","url":"https://pubmed.ncbi.nlm.nih.gov/38588410","citation_count":10,"is_preprint":false},{"pmid":"36788088","id":"PMC_36788088","title":"Nonredundant Upregulation of CD112R (PVRIG) and PD-1 on Cytotoxic T Lymphocytes Located in T Cell Nests of Colorectal Cancer.","date":"2023","source":"Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc","url":"https://pubmed.ncbi.nlm.nih.gov/36788088","citation_count":10,"is_preprint":false},{"pmid":"39851063","id":"PMC_39851063","title":"Co-blocking TIGIT and PVRIG Using a Novel Bispecific Antibody Enhances Antitumor Immunity.","date":"2025","source":"Molecular cancer therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/39851063","citation_count":7,"is_preprint":false},{"pmid":"38626767","id":"PMC_38626767","title":"Structural basis for the immune recognition and selectivity of the immune receptor PVRIG for ligand Nectin-2.","date":"2024","source":"Structure (London, England : 1993)","url":"https://pubmed.ncbi.nlm.nih.gov/38626767","citation_count":5,"is_preprint":false},{"pmid":"38554184","id":"PMC_38554184","title":"Characterization of a novel anti-PVRIG antibody with Fc-competent function that exerts strong antitumor effects via NK activation in preclinical models.","date":"2024","source":"Cancer immunology, immunotherapy : CII","url":"https://pubmed.ncbi.nlm.nih.gov/38554184","citation_count":3,"is_preprint":false},{"pmid":"40425968","id":"PMC_40425968","title":"Investigation of TIGIT, PVRIG, CD112 and CD155 expression in early and late onset preeclampsia.","date":"2025","source":"Journal of molecular histology","url":"https://pubmed.ncbi.nlm.nih.gov/40425968","citation_count":0,"is_preprint":false},{"pmid":"39694409","id":"PMC_39694409","title":"The inhibitory receptor PVRIG is dominantly expressed in the bone marrow of patients with multiple myeloma and its blockade enhances T-cell engager's immune activation.","date":"2024","source":"Experimental hematology","url":"https://pubmed.ncbi.nlm.nih.gov/39694409","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.02.19.25322384","title":"Downregulation of cancer hallmarks and immune check-points in patients with glioblastoma following a short course of the pro-oxidant combination of Resveratrol and Copper","date":"2025-02-24","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.19.25322384","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.01.16.633312","title":"Epigenetic Modulation of Host Immunity related genes in Pulmonary Tuberculosis: A Comprehensive Analysis of DNA Methylation Profiles in Peripheral Blood Mononuclear Cells","date":"2025-01-18","source":"bioRxiv","url":"https://doi.org/10.1101/2025.01.16.633312","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11990,"output_tokens":2546,"usd":0.03708,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9829,"output_tokens":3250,"usd":0.065198,"stage2_stop_reason":"end_turn"},"total_usd":0.102278,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"CD112R (PVRIG) is a coinhibitory receptor expressed preferentially on T cells that inhibits TCR-mediated signals; its ligand is CD112 (PVRL2/Nectin-2), which is widely expressed on antigen-presenting cells and tumor cells, and CD112R competes with CD226 for CD112 binding. Disrupting the CD112R-CD112 interaction enhances human T cell response.\",\n      \"method\": \"Receptor-ligand binding assays, T cell functional assays (TCR-mediated signaling readouts), competition binding with CD226, blockade experiments\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal binding assays, functional T cell assays, competition binding, independently replicated in subsequent studies\",\n      \"pmids\": [\"26755705\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CD112R (PVRIG) is expressed on human NK cells, and blockade of CD112R (separately or in combination with TIGIT) enhances NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) triggered by trastuzumab. TIGIT (but not CD112R) is preferentially expressed on CD16+ NK cell subset and is upregulated upon NK cell activation via ADCC.\",\n      \"method\": \"Flow cytometry, NK cell functional assays (ADCC, cytotoxicity), antibody blockade of CD112R and TIGIT\",\n      \"journal\": \"Cancer immunology, immunotherapy : CII\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional NK cell assays with blockade, single lab, multiple readouts\",\n      \"pmids\": [\"28623459\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PVRIG antagonism increases CD8+ T cell cytokine production and cytotoxic activity. The inhibitory effect of PVRL2 on T cells is mediated specifically by PVRIG and not TIGIT, establishing PVRIG-PVRL2 as a nonredundant signaling node distinct from TIGIT-PVR. Combined PVRIG and TIGIT or PD-1 blockade further increases T cell activation.\",\n      \"method\": \"Antibody blockade of PVRIG, TIGIT, and PD-1; CD8+ T cell cytokine production assays; cytotoxicity assays; tumor-infiltrating lymphocyte (TIL) functional assays\",\n      \"journal\": \"Cancer immunology research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal functional assays (cytokine, cytotoxicity, TIL), nonredundancy demonstrated by selective pathway blockade, replicated across conditions\",\n      \"pmids\": [\"30659054\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Murine PVRIG binds PVRL2 strongly (principal ligand) and interacts weakly with PVR. PVRIG-deficient mouse CD8+ T cells mount a stronger antigen-specific effector response during acute Listeria monocytogenes infection. In the tumor microenvironment, infiltrating CD8+ T cells express PVRIG while its ligand PVRL2 is detected predominantly on myeloid cells and tumor cells.\",\n      \"method\": \"PVRIG knockout mice, Listeria infection model, tumor growth assays in PVRIG-/- vs. wild-type mice, flow cytometry for receptor/ligand expression, binding assays\",\n      \"journal\": \"Cancer immunology research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO with defined phenotypic readout, binding assay for ligand selectivity, in vivo tumor models, multiple orthogonal methods\",\n      \"pmids\": [\"30659055\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PVRIG blockade in NK cells slows tumor growth in murine models and prolongs survival by inhibiting NK cell exhaustion as well as CD8+ T cell exhaustion. In Rag1-/- mice (lacking adaptive immunity), PVRIG blockade still provided therapeutic effect, demonstrating a T cell-independent NK-cell-mediated mechanism. NK cells are required for anti-tumor efficacy of PVRIG blockade.\",\n      \"method\": \"PVRIG-deficient mice, Rag1-/- mice, NK/CD8+ T cell depletion in vivo, syngeneic and xenograft tumor models, NK cell functional assays\",\n      \"journal\": \"Journal of hematology & oncology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO, cell depletion experiments, Rag1-/- immunodeficient model, multiple tumor models establishing NK cell-intrinsic mechanism\",\n      \"pmids\": [\"34174928\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"NK cell activation (via tumor cell recognition, cytokines IL-2/IL-12, or activating receptor stimulation via CD16 and NKp46) causes reduced PVRIG surface expression. PVRIG is present at higher levels in the cytoplasm than on the cell surface (especially in CD56bright NK cells), and is continually transported to the cell surface via the ER and Golgi in both unstimulated and activated NK cells.\",\n      \"method\": \"Flow cytometry for surface vs. cytoplasmic PVRIG, ER/Golgi trafficking inhibitors, NK cell activation assays, immunofluorescence\",\n      \"journal\": \"Haematologica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiments (cytoplasmic vs. surface), trafficking pathway determination, multiple activation stimuli tested, single lab\",\n      \"pmids\": [\"33147937\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Crystal structure of PVRIG in complex with Nectin-2 (PVRL2) reveals that PVRIG possesses a unique CC' loop that complements a double-lock-and-key binding mode contributing to its high affinity for Nectin-2. Charged residues in the F-strands determine ligand selectivity of PVRIG for Nectin-2 but not Necl-5 (CD155/PVR).\",\n      \"method\": \"X-ray crystallography (crystal structure of PVRIG–Nectin-2 complex), binding affinity comparisons across co-receptors and ligands\",\n      \"journal\": \"Structure (London, England : 1993)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with functional validation of binding mode and selectivity determinants, single rigorous study with structural and binding data\",\n      \"pmids\": [\"38626767\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"An anti-PVRIG antibody with Fc-competent function (IBI352g4a) binds the extracellular domain of human PVRIG with high affinity (Kd = 0.53 nM) and fully blocks PVRIG-PVRL2 interaction. In vitro, it significantly induces NK cell activation and degranulation but has minimal effect on T cell activation. In vivo, both NK and T cells contribute to antitumor effect, but NK cells play predominant roles; Fc effector function is critical for both NK cell activation and treatment efficacy.\",\n      \"method\": \"Binding affinity assay (SPR/ELISA), in vitro NK and T cell functional assays, in vivo tumor models with NK/T cell depletion, Fc-effector-function analysis\",\n      \"journal\": \"Cancer immunology, immunotherapy : CII\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — binding assay, in vitro functional assays, in vivo depletion experiments, single lab, multiple methods\",\n      \"pmids\": [\"38554184\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PVRL2 (CD112) suppresses antitumor immunity through mechanisms beyond PVRIG: deletion of PVRL2 in syngeneic tumor models dramatically reduced tumor growth even in the absence of PVRIG. PVRIG loss showed no additive effect in the absence of PVRL2, placing PVRIG downstream of or dependent on PVRL2 in this pathway. PVRL2 suppresses CD8+ T and NK cells in the tumor microenvironment.\",\n      \"method\": \"PVRL2 gene deletion in syngeneic mouse tumor models, PVRIG KO mice, combinatorial KO epistasis analysis, immune cell depletion\",\n      \"journal\": \"Cancer immunology research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with double KO models, multiple syngeneic tumor models, defines pathway hierarchy between PVRIG and PVRL2\",\n      \"pmids\": [\"38588410\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PVRIG (CD112R) is a coinhibitory immune checkpoint receptor expressed on T cells and NK cells that binds PVRL2 (Nectin-2/CD112) with high affinity via a unique CC' loop and charged F-strand residues (crystal structure resolved), competing with the costimulatory receptor CD226; engagement of PVRIG by PVRL2 inhibits TCR-mediated T cell signaling and NK cell activation, constituting a nonredundant inhibitory axis distinct from TIGIT-PVR, with PVRIG trafficking continuously from the ER/Golgi to the cell surface and being downregulated upon NK cell activation, and its blockade (alone or in combination with TIGIT or PD-1 blockade) enhancing CD8+ T cell effector function and NK cell cytotoxicity to suppress tumor growth in vivo.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PVRIG (CD112R) is a coinhibitory immune checkpoint receptor expressed on T cells and NK cells that restrains antitumor immunity by engaging the nectin ligand PVRL2 (CD112/Nectin-2) [#0, #3]. On T cells, PVRIG binds PVRL2 and competes with the costimulatory receptor CD226 for ligand, and its engagement dampens TCR-mediated signaling; disrupting the PVRIG-PVRL2 interaction enhances CD8+ T cell cytokine production and cytotoxicity [#0, #2]. The PVRIG-PVRL2 axis is nonredundant with the TIGIT-PVR axis, with PVRL2-mediated T cell inhibition transmitted specifically through PVRIG rather than TIGIT, such that combined PVRIG, TIGIT, or PD-1 blockade gives additive activation [#2]. Structurally, PVRIG achieves high-affinity, selective recognition of Nectin-2 through a unique CC' loop that supports a double-lock-and-key binding mode and charged F-strand residues that discriminate Nectin-2 from CD155/PVR [#6]. On NK cells, PVRIG blockade enhances ADCC and cytotoxicity and reverses NK cell exhaustion, and genetic and depletion studies establish an NK-cell-intrinsic, T cell-independent antitumor mechanism [#1, #4]. Surface PVRIG is downregulated upon NK cell activation while the protein is continuously trafficked from the ER and Golgi to the cell surface, with a larger cytoplasmic than surface pool [#5]. Epistasis analysis places PVRIG within the broader immunosuppressive activity of PVRL2, as PVRL2 deletion suppresses tumor growth even without PVRIG and PVRIG loss confers no further benefit in the absence of PVRL2 [#8].\",\n  \"teleology\": [\n    {\n      \"year\": 2016,\n      \"claim\": \"Established PVRIG as a coinhibitory receptor on T cells, identifying its ligand and its competition with the activating receptor CD226 — defining the molecular basis of a new inhibitory axis.\",\n      \"evidence\": \"Receptor-ligand and competition binding assays with CD226, plus TCR-signaling functional readouts in human T cells\",\n      \"pmids\": [\"26755705\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream signaling motifs transmitting the inhibitory signal not defined\", \"Did not resolve relative contributions of PVRIG vs. CD226 in physiological settings\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Extended PVRIG function to NK cells, showing blockade augments antibody-dependent cytotoxicity and distinguishing its expression pattern from TIGIT.\",\n      \"evidence\": \"Flow cytometry and NK cell ADCC/cytotoxicity assays with PVRIG and TIGIT antibody blockade\",\n      \"pmids\": [\"28623459\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab functional data\", \"Mechanism of NK inhibition not dissected at signaling level\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrated that PVRL2-mediated inhibition of CD8+ T cells runs specifically through PVRIG and not TIGIT, establishing PVRIG-PVRL2 as a nonredundant node combinable with TIGIT and PD-1 blockade.\",\n      \"evidence\": \"Selective antibody blockade of PVRIG/TIGIT/PD-1 with CD8+ T cell cytokine, cytotoxicity, and TIL functional assays\",\n      \"pmids\": [\"30659054\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish ligand selectivity at structural level\", \"Combination synergy mechanism not mapped\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Genetic knockout confirmed PVRIG as a bona fide inhibitory receptor in vivo, with PVRL2 as principal ligand and weak PVR binding, and defined the receptor/ligand cellular compartments in the tumor microenvironment.\",\n      \"evidence\": \"PVRIG knockout mice, Listeria infection and tumor models, binding assays, flow cytometry for receptor/ligand expression\",\n      \"pmids\": [\"30659055\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of weak PVR interaction unresolved\", \"Cell-intrinsic signaling output not characterized\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Resolved whether PVRIG blockade efficacy depends on adaptive immunity by showing an NK-cell-intrinsic, T-cell-independent antitumor mechanism that reverses NK and CD8+ T cell exhaustion.\",\n      \"evidence\": \"PVRIG-deficient and Rag1-/- mice with NK/CD8 depletion across syngeneic and xenograft tumor models\",\n      \"pmids\": [\"34174928\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of exhaustion reversal not defined\", \"Relative NK vs. T contribution context-dependent\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined PVRIG subcellular dynamics, showing a predominantly cytoplasmic pool, continuous ER/Golgi-to-surface trafficking, and surface downregulation upon NK activation.\",\n      \"evidence\": \"Surface vs. cytoplasmic flow cytometry, trafficking inhibitors, immunofluorescence, multiple NK activation stimuli\",\n      \"pmids\": [\"33147937\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Trafficking regulatory machinery unidentified\", \"Functional consequence of activation-induced downregulation unclear\", \"Single lab\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Crystal structure of the PVRIG-Nectin-2 complex defined the structural determinants of high-affinity binding and ligand selectivity.\",\n      \"evidence\": \"X-ray crystallography of PVRIG-Nectin-2 complex with binding affinity comparisons across co-receptors and ligands\",\n      \"pmids\": [\"38626767\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure does not address intracellular signaling\", \"Apo PVRIG conformation and competitive interface with CD226 not co-resolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Tested a therapeutic Fc-competent anti-PVRIG antibody, showing blockade preferentially drives NK cell activation and that Fc effector function is critical for efficacy.\",\n      \"evidence\": \"SPR/ELISA binding (Kd 0.53 nM), in vitro NK and T cell assays, in vivo tumor models with depletion and Fc-effector analysis\",\n      \"pmids\": [\"38554184\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab antibody-specific findings\", \"Mechanistic basis for NK-over-T selectivity not resolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Genetic epistasis placed PVRIG within the broader immunosuppressive activity of PVRL2, showing PVRL2 acts through PVRIG-independent routes and PVRIG loss adds nothing without PVRL2.\",\n      \"evidence\": \"PVRL2 and PVRIG single and double knockout syngeneic tumor models with immune cell depletion\",\n      \"pmids\": [\"38588410\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of additional PVRL2 receptors mediating PVRIG-independent suppression not defined\", \"Pathway hierarchy in human disease not validated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The intracellular signaling cascade by which PVRIG transmits its inhibitory signal upon PVRL2 engagement remains uncharacterized in the available corpus.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No cytoplasmic-domain signaling motifs or downstream effectors identified\", \"Mechanism of CD226 antagonism at the signaling level unresolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 2, 3]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [0, 2, 3, 4]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"PVRL2\", \"CD226\", \"TIGIT\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}