{"id":"7cd1b53c-c139-5eb1-956d-2f562ca6bba0","stable_key":"10629adf-a816-5b7b-82db-a76bfbb946f2:bg-cr3-has-a-lectin-site","predicate":"binds","statement":"CR3 serves as the leukocyte beta-glucan receptor through a cation-independent lectin site located C-terminal to the I-domain of CD11b that contains the binding sites for iC3b, ICAM-1 and fibrinogen, a 10-kilodalton soluble zymosan polysaccharide consisting largely of mannose and approximately 5% glucose bound with high affinity of 6.7 x 10(-8) M, binding was blocked not only by pure beta-glucans from yeast, mushroom, seaweed or barley but also by N-acetyl-D-glucosamine and alpha- or beta-methylmannoside and alpha- or beta-methylglucoside, and its sugar specificity is broader than originally appreciated.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"1b5d6d4a-792c-5658-8e94-53ae25fda1dc","mechanism_event_label":"The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.","subject":{"id":"d5d2deaa-4b05-570a-a958-c64d8c19a177","slug":"cr3-lectin-site","display_name":"The lectin site of CD11b C-terminal to the I-domain","entity_type_key":"protein_state"},"object":{"id":"1e73e18e-eca0-56b0-b3de-a850ea95344f","slug":"beta-glucan","display_name":"Beta-glucan","entity_type_key":"chemical_species"},"evidence_count":1,"mechanism_event":{"id":"1b5d6d4a-792c-5658-8e94-53ae25fda1dc","stable_key":"10629adf-a816-5b7b-82db-a76bfbb946f2:bg-cr3-has-a-lectin-site-event","event_type":"biochemical_relationship","label":"The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.","description":"CR3 serves as the leukocyte beta-glucan receptor through a cation-independent lectin site located C-terminal to the I-domain of CD11b that contains the binding sites for iC3b, ICAM-1 and fibrinogen, a 10-kilodalton soluble zymosan polysaccharide consisting largely of mannose and approximately 5% glucose bound with high affinity of 6.7 x 10(-8) M, binding was blocked not only by pure beta-glucans from yeast, mushroom, seaweed or barley but also by N-acetyl-D-glucosamine and alpha- or beta-methylmannoside and alpha- or beta-methylglucoside, and its sugar specificity is broader than originally appreciated.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"a06749c1-3762-5f7b-9de7-5862879dfb30","slug":"itgam","display_name":"Integrin alpha-M / CD11b / ITGAM","entity_type_key":"protein"},"role":"host_protein","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"b3722d48-0326-5143-9e22-e3bb284f3bce","slug":"cr3-i-domain","display_name":"The I-domain of CD11b","entity_type_key":"protein_state"},"role":"separate_site","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"982d0545-312b-52d8-926a-edc95e4a2aa2","slug":"soluble-zymosan-polysaccharide","display_name":"A 10-kilodalton soluble zymosan polysaccharide","entity_type_key":"chemical_species"},"role":"highest_affinity_ligand","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"13d8808b-2a95-5427-b681-5b389c0b694b","slug":"barley-beta-glucan","display_name":"Barley mixed-linkage beta-(1->3)/(1->4)-glucan","entity_type_key":"chemical_species"},"role":"competing_ligand","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"919e84e7-6b11-59de-a10b-8b844b1e72f3","slug":"yeast-beta-glucan","display_name":"Yeast beta-(1->3)/(1->6)-glucan","entity_type_key":"chemical_species"},"role":"competing_ligand","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"34c2ee55-a44b-5987-b45a-eedd946962a0","slug":"glucan-binding-affinity","display_name":"Binding affinity of a glucan for its receptor","entity_type_key":"cellular_process"},"role":"measured_property","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""},{"entity":{"id":"d5d2deaa-4b05-570a-a958-c64d8c19a177","slug":"cr3-lectin-site","display_name":"The lectin site of CD11b C-terminal to the I-domain","entity_type_key":"protein_state"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":6,"notes":""},{"entity":{"id":"1e73e18e-eca0-56b0-b3de-a850ea95344f","slug":"beta-glucan","display_name":"Beta-glucan","entity_type_key":"chemical_species"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":7,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/glucan-research/8558003.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"00a0fef65e91375066fe9920200032466aec1c0d85bf548d53f64c3d384106b7\", \"start_char\": 0, \"end_char\": 1936, \"text_sha256\": \"00a0fef65e91375066fe9920200032466aec1c0d85bf548d53f64c3d384106b7\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Flow cytometry with labelled soluble polysaccharides, CR3 and CR4 chimeras, and a panel of domain-specific antibodies","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Labelled beta-glucans from yeast, mushroom, seaweed and barley, and a 10-kilodalton soluble zymosan polysaccharide","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Binding and inhibition rather than function. The highest-affinity ligand measured was not a pure beta-glucan but a mannose-rich zymosan polysaccharide, and the sugar specificity proved broader than beta-glucan alone.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Beta-glucan research collection; topical membership is not evidence of a direct clinical effect, and each preparation is recorded as its own entity with no family link joining any pair.","comparator":null,"unit":null,"notes":"","entity":{"slug":"beta-glucan","display_name":"Beta-glucan","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Human","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[bg-p8558003] Analysis of the sugar specificity and molecular location of the beta-glucan-binding lectin site of complement receptor type 3 (CD11b/CD18). (1996). https://pubmed.ncbi.nlm.nih.gov/8558003/ DOI: 10.4049/jimmunol.156.3.1235","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Leukocytes","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"d8bbbb30-a850-5750-a851-d4f85ae04890","evidence_kind":"source_excerpt","locator":"Lines 203-214","start_line":203,"end_line":214,"excerpt":"### bg-cr3-has-a-lectin-site\nCR3 serves as the leukocyte beta-glucan receptor through a cation-independent lectin site located C-terminal to the I-domain of CD11b that contains the binding sites for iC3b, ICAM-1 and fibrinogen, a 10-kilodalton soluble zymosan polysaccharide consisting largely of mannose and approximately 5% glucose bound with high affinity of 6.7 x 10(-8) M, binding was blocked not only by pure beta-glucans from yeast, mushroom, seaweed or barley but also by N-acetyl-D-glucosamine and alpha- or beta-methylmannoside and alpha- or beta-methylglucoside, and its sugar specificity is broader than originally appreciated.\nCondition category: normal\nnutrient_topic: Beta-glucan research collection; topical membership is not evidence of a direct clinical effect, and each preparation is recorded as its own entity with no family link joining any pair.\nplain_language: The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.\norganism: Human\ntissue_or_cell_type: Leukocytes\nexperimental_model: Flow cytometry with labelled soluble polysaccharides, CR3 and CR4 chimeras, and a panel of domain-specific antibodies\nlimitations: Binding and inhibition rather than function. The highest-affinity ligand measured was not a pure beta-glucan but a mannose-rich zymosan polysaccharide, and the sugar specificity proved broader than beta-glucan alone.\nexposure: Labelled beta-glucans from yeast, mushroom, seaweed and barley, and a 10-kilodalton soluble zymosan polysaccharide\nevidence_span: {\"source_cache\": \"artifacts/glucan-research/8558003.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"00a0fef65e91375066fe9920200032466aec1c0d85bf548d53f64c3d384106b7\", \"start_char\": 0, \"end_char\": 1936, \"text_sha256\": \"00a0fef65e91375066fe9920200032466aec1c0d85bf548d53f64c3d384106b7\"}\n[bg-p8558003] Analysis of the sugar specificity and molecular location of the beta-glucan-binding lectin site of complement receptor type 3 (CD11b/CD18). (1996). https://pubmed.ncbi.nlm.nih.gov/8558003/ DOI: 10.4049/jimmunol.156.3.1235","model_system":"Flow cytometry with labelled soluble polysaccharides, CR3 and CR4 chimeras, and a panel of domain-specific antibodies","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [bg-p8558003] Analysis of the sugar specificity and molecular location of the beta-glucan-binding lectin site of complement receptor type 3 (CD11b/CD18). (1996). https://pubmed.ncbi.nlm.nih.gov/8558003/ DOI: 10.4049/jimmunol.156.3.1235","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"74dc223d-8289-57bf-a731-d220fa017c1e","stable_key":"import-10629adf-a816-5b7b-82db-a76bfbb946f2","title":"Beta-glucan: a structural family rather than an agent, what decides whether a bound glucan actually signals, the complement route that a cereal and a yeast preparation share, and the unequal human evidence behind each (2026-09-22)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"7c62f2d2f8d99b650e6dc26a505b0f053ae1c8bdb38099d4dfc0771f65287461","revision_id":"a53bb794-0a4b-525d-9cf7-22b46a5403b0","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[{"id":"31152449-e8e0-5410-96b2-b4183481c40a","title":"Do cereal and fungal beta-glucans have separate mechanisms, one metabolic and one immune?","kind":"qualification","status":"open","why":"The evidence bases do differ, and sharply. What cereal beta-glucan has in humans is modest LDL lowering and a reduced acute glycaemic response, both established across dozens of randomised trials and both accepted by a regulator with an exact dose attached. What the fungal and yeast preparations have is receptor pharmacology, trained immunity and oncology trials. That difference is real and it is what should govern any practical statement. It is not, however, a boundary between two kinds of molecule. One experiment gave mice oral barley mixed-linkage glucan and oral yeast branched glucan in the same protocol and found that both potentiated an antitumour antibody, with therapeutic failure in C3-deficient and CR3-deficient animals in each case, so the two converged on one complement-dependent route. A separate line reaches immunity from the other direction: oat beta-glucan improved anti-PD-1 efficacy in mice by expanding a gut bacterium whose butyrate and indole-3-propionic acid activated dendritic cells and CD8 T cells. The binding record points the same way, since pure beta-glucans from barley blocked the CR3 lectin site alongside those from yeast, mushroom and seaweed. The defensible statement is that the mechanisms overlap and the human evidence does not: a cereal glucan is not immunologically inert, and an immune effect in a mouse is not a treatment for a person.","resolution":"Resolved against a categorical split. The separation that survives is one of evidence strength per preparation and endpoint, not of mechanism.","created_at":"2026-09-22 23:28:00","record_type":"conflict","display_label":"Recorded conflict","record_url":"/conflicts/31152449-e8e0-5410-96b2-b4183481c40a","sides":[{"conflict_id":"31152449-e8e0-5410-96b2-b4183481c40a","ordinal":0,"label":"Three grams a day takes about a quarter of a millimole off the harmful cholesterol and leaves the other lipids alone.","revision_id":"a53bb794-0a4b-525d-9cf7-22b46a5403b0","start_line":489,"end_line":500,"quote":"### bg-oat-glucan-lowers-ldl\nOat beta-glucan in doses at or above 3 grams per day reduced low-density lipoprotein and total cholesterol relative to control by 0.25 mmol/L with 95% CI 0.20 to 0.30 and 0.30 mmol/L with 95% CI 0.24 to 0.35 respectively, there was no significant effect on high-density lipoprotein cholesterol or triglycerides and no evidence that dose across a range of 3.0 to 12.4 grams per day or duration of treatment from 2 to 12 weeks influenced the results, and LDL cholesterol lowering was significantly greater with higher baseline LDL cholesterol.\nCondition category: normal\nnutrient_topic: Beta-glucan research collection; topical membership is not evidence of a direct clinical effect, and each preparation is recorded as its own entity with no family link joining any pair.\nplain_language: Three grams a day takes about a quarter of a millimole off the harmful cholesterol and leaves the other lipids alone.\norganism: Human\ntissue_or_cell_type: Serum lipids\nexperimental_model: Random-effects meta-analysis and meta-regression of 28 randomised controlled trials at or above 3 grams per day\nlimitations: A meta-analysis with some indication of heterogeneity. The diabetes subgroup rests on few studies, and in-house study reports from a commercial source were among those searched.\nexposure: Oat beta-glucan at 3.0 to 12.4 grams per day against an appropriate control for 2 to 12 weeks\nevidence_span: {\"source_cache\": \"artifacts/glucan-research/25411276.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"33075c61a20f22975ba8719b6ef8834ce254f1d4e3ede6ca5d89cd4d81a82b28\", \"start_char\": 0, \"end_char\": 2072, \"text_sha256\": \"33075c61a20f22975ba8719b6ef8834ce254f1d4e3ede6ca5d89cd4d81a82b28\"}\n[bg-p25411276] Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials. (2014). https://pubmed.ncbi.nlm.nih.gov/25411276/ DOI: 10.3945/ajcn.114.086108","source_key":"import-10629adf-a816-5b7b-82db-a76bfbb946f2","source_title":"Beta-glucan: a structural family rather than an agent, what decides whether a bound glucan actually signals, the complement route that a cereal and a yeast preparation share, and the unequal human evidence behind each (2026-09-22)","claim_ids":["08ac8d7c-ab18-5fb6-a5c6-a9c89c76dc52"]},{"conflict_id":"31152449-e8e0-5410-96b2-b4183481c40a","ordinal":1,"label":"A cereal glucan and a yeast glucan did the same job by the same route, which is the result that refuses to let the two be filed apart.","revision_id":"a53bb794-0a4b-525d-9cf7-22b46a5403b0","start_line":242,"end_line":253,"quote":"### bg-barley-and-yeast-converge\nRecent data indicated that barley beta-1,3;1,4-glucan given orally potentiated the activity of antitumour monoclonal antibody leading to enhanced tumour regression and survival, and this investigation showed that orally administered yeast beta-1,3;1,6-glucan functioned similarly to barley beta-1,3;1,4-glucan with antitumour monoclonal antibody, with both oral beta-1,3-glucans a requirement for iC3b on tumours and CR3 on granulocytes being confirmed by demonstrating therapeutic failures in mice deficient in C3 or CR3.\nCondition category: machinery_impairment\nnutrient_topic: Beta-glucan research collection; topical membership is not evidence of a direct clinical effect, and each preparation is recorded as its own entity with no family link joining any pair.\nplain_language: A cereal glucan and a yeast glucan did the same job by the same route, which is the result that refuses to let the two be filed apart.\norganism: Mouse\ntissue_or_cell_type: Gut, spleen, lymph node, bone marrow and tumour\nexperimental_model: Fluorescein-labelled oral glucans tracked through macrophages to marrow, with therapy in C3-deficient and CR3-deficient mice\nlimitations: The single experiment in this collection that tested a cereal mixed-linkage glucan and a yeast branched glucan side by side in the same protocol. It is a mouse tumour model, and oral uptake in mice does not establish the same uptake in people.\nexposure: Orally administered barley beta-1,3;1,4-glucan and orally administered yeast beta-1,3;1,6-glucan, each with antitumour monoclonal antibody\nevidence_span: {\"source_cache\": \"artifacts/glucan-research/15240666.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"eaff7297fa40df19ef82e5e1de433ec0cf34590a7e3fda6aa6061e0922666781\", \"start_char\": 0, \"end_char\": 1454, \"text_sha256\": \"eaff7297fa40df19ef82e5e1de433ec0cf34590a7e3fda6aa6061e0922666781\"}\n[bg-p15240666] Mechanism by which orally administered beta-1,3-glucans enhance the tumoricidal activity of antitumor monoclonal antibodies in murine tumor models. (2004). https://pubmed.ncbi.nlm.nih.gov/15240666/ DOI: 10.4049/jimmunol.173.2.797","source_key":"import-10629adf-a816-5b7b-82db-a76bfbb946f2","source_title":"Beta-glucan: a structural family rather than an agent, what decides whether a bound glucan actually signals, the complement route that a cereal and a yeast preparation share, and the unequal human evidence behind each (2026-09-22)","claim_ids":["ec9b6b52-9f1e-53ff-90df-a03d7c8b4a15"]},{"conflict_id":"31152449-e8e0-5410-96b2-b4183481c40a","ordinal":2,"label":"The cereal glucan never touches the tumour; it feeds a gut bacterium whose products wake the cells that do.","revision_id":"a53bb794-0a4b-525d-9cf7-22b46a5403b0","start_line":658,"end_line":669,"quote":"### bg-a-cereal-glucan-reaches-immunity\nOat-beta-glucan enhances anti-PD-1 efficacy in murine models by selectively expanding Faecalibacterium prausnitzii, combining anti-PD-1 with either oat-beta-glucan or F. prausnitzii boosts intratumoral dendritic cell and CD8+ T cell infiltration and cytotoxic activation compared with anti-PD-1 monotherapy, metabolomics identifies F. prausnitzii-derived butyrate and indole-3-propionic acid as key mediators with butyrate activating dendritic cells via the HDAC8, H3K27ac and NF-kappa-B p65 pathway, in a colorectal cancer cohort undergoing anti-PD-1 treatment higher baseline F. prausnitzii abundance and elevated plasma butyrate and indole-3-propionic acid correlate with improved responses, and a human intervention study confirms oat-beta-glucan safety, its ability to increase butyrate and indole-3-propionic acid, and its capacity to modulate F. prausnitzii.\nCondition category: normal\nnutrient_topic: Beta-glucan research collection; topical membership is not evidence of a direct clinical effect, and each preparation is recorded as its own entity with no family link joining any pair.\nplain_language: The cereal glucan never touches the tumour; it feeds a gut bacterium whose products wake the cells that do.\norganism: Mouse\ntissue_or_cell_type: Gut microbiota and tumour microenvironment\nexperimental_model: Murine tumour models with selective bacterial expansion and metabolomics, plus a human cohort and a human intervention study\nlimitations: The causal efficacy claim is demonstrated in mice. The human components are a correlation in a colorectal cancer cohort and an intervention study reporting safety and metabolite change, so no anticancer benefit in people is established here.\nexposure: Oat beta-glucan with anti-PD-1 checkpoint blockade in mice, and oat beta-glucan supplementation in people\nevidence_span: {\"source_cache\": \"artifacts/glucan-research/42214334.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"1e145fb1c4163d9e0cd10a4055b68fa47de521dcf19d25253d42fc9c971d56ba\", \"start_char\": 0, \"end_char\": 1310, \"text_sha256\": \"1e145fb1c4163d9e0cd10a4055b68fa47de521dcf19d25253d42fc9c971d56ba\"}\n[bg-p42214334] Oat-β-glucan potentiates anti-PD-1 efficacy through Faecalibacterium prausnitzii-derived butyrate and indole-3-propionic acid. (2026). https://pubmed.ncbi.nlm.nih.gov/42214334/ DOI: 10.1016/j.chom.2026.05.002","source_key":"import-10629adf-a816-5b7b-82db-a76bfbb946f2","source_title":"Beta-glucan: a structural family rather than an agent, what decides whether a bound glucan actually signals, the complement route that a cereal and a yeast preparation share, and the unequal human evidence behind each (2026-09-22)","claim_ids":["3a2db75e-b8d2-51fd-9b9d-a9825361a4cb"]},{"conflict_id":"31152449-e8e0-5410-96b2-b4183481c40a","ordinal":3,"label":"The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.","revision_id":"a53bb794-0a4b-525d-9cf7-22b46a5403b0","start_line":203,"end_line":214,"quote":"### bg-cr3-has-a-lectin-site\nCR3 serves as the leukocyte beta-glucan receptor through a cation-independent lectin site located C-terminal to the I-domain of CD11b that contains the binding sites for iC3b, ICAM-1 and fibrinogen, a 10-kilodalton soluble zymosan polysaccharide consisting largely of mannose and approximately 5% glucose bound with high affinity of 6.7 x 10(-8) M, binding was blocked not only by pure beta-glucans from yeast, mushroom, seaweed or barley but also by N-acetyl-D-glucosamine and alpha- or beta-methylmannoside and alpha- or beta-methylglucoside, and its sugar specificity is broader than originally appreciated.\nCondition category: normal\nnutrient_topic: Beta-glucan research collection; topical membership is not evidence of a direct clinical effect, and each preparation is recorded as its own entity with no family link joining any pair.\nplain_language: The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.\norganism: Human\ntissue_or_cell_type: Leukocytes\nexperimental_model: Flow cytometry with labelled soluble polysaccharides, CR3 and CR4 chimeras, and a panel of domain-specific antibodies\nlimitations: Binding and inhibition rather than function. The highest-affinity ligand measured was not a pure beta-glucan but a mannose-rich zymosan polysaccharide, and the sugar specificity proved broader than beta-glucan alone.\nexposure: Labelled beta-glucans from yeast, mushroom, seaweed and barley, and a 10-kilodalton soluble zymosan polysaccharide\nevidence_span: {\"source_cache\": \"artifacts/glucan-research/8558003.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"00a0fef65e91375066fe9920200032466aec1c0d85bf548d53f64c3d384106b7\", \"start_char\": 0, \"end_char\": 1936, \"text_sha256\": \"00a0fef65e91375066fe9920200032466aec1c0d85bf548d53f64c3d384106b7\"}\n[bg-p8558003] Analysis of the sugar specificity and molecular location of the beta-glucan-binding lectin site of complement receptor type 3 (CD11b/CD18). (1996). https://pubmed.ncbi.nlm.nih.gov/8558003/ DOI: 10.4049/jimmunol.156.3.1235","source_key":"import-10629adf-a816-5b7b-82db-a76bfbb946f2","source_title":"Beta-glucan: a structural family rather than an agent, what decides whether a bound glucan actually signals, the complement route that a cereal and a yeast preparation share, and the unequal human evidence behind each (2026-09-22)","claim_ids":["7cd1b53c-c139-5eb1-956d-2f562ca6bba0"]}]},{"id":"9b957712-74e1-5f44-b1e6-72f51f1cff1d","title":"Which receptor is the leukocyte beta-glucan receptor?","kind":"qualification","status":"open","why":"Two papers a few years apart each announce that they have identified the long-sought leukocyte beta-glucan receptor, and they name different molecules. The earlier concludes that CR3 serves that role through a cation-independent lectin site C-terminal to the CD11b I-domain, with binding blocked by pure beta-glucans from four different sources. The later finds that non-opsonic zymosan binding is entirely unaffected by genetic CD11b deficiency or by a blocking anti-CR3 antibody, and that Dectin-1 is almost exclusively responsible, describing this as resolving the controversy. The records are not actually incompatible once the endpoints are separated: the first measured binding and inhibition, the second measured non-opsonic recognition of a particle, and a receptor can bind a ligand without being the one that mediates a given cellular response. Both receptors carry claims elsewhere in this collection, and the antitumour records depend on CR3 while the antifungal signalling records depend on Dectin-1. The highest-affinity ligand in the CR3 work was also not a pure beta-glucan but a mannose-rich zymosan polysaccharide, which weakens any reading of it as a pure glucan affinity.","resolution":"Unresolved as posed; the question assumes a single receptor. Both bind glucans and they carry different functions in the records here.","created_at":"2026-09-22 23:28:00","record_type":"conflict","display_label":"Recorded conflict","record_url":"/conflicts/9b957712-74e1-5f44-b1e6-72f51f1cff1d","sides":[{"conflict_id":"9b957712-74e1-5f44-b1e6-72f51f1cff1d","ordinal":0,"label":"The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.","revision_id":"a53bb794-0a4b-525d-9cf7-22b46a5403b0","start_line":203,"end_line":214,"quote":"### bg-cr3-has-a-lectin-site\nCR3 serves as the leukocyte beta-glucan receptor through a cation-independent lectin site located C-terminal to the I-domain of CD11b that contains the binding sites for iC3b, ICAM-1 and fibrinogen, a 10-kilodalton soluble zymosan polysaccharide consisting largely of mannose and approximately 5% glucose bound with high affinity of 6.7 x 10(-8) M, binding was blocked not only by pure beta-glucans from yeast, mushroom, seaweed or barley but also by N-acetyl-D-glucosamine and alpha- or beta-methylmannoside and alpha- or beta-methylglucoside, and its sugar specificity is broader than originally appreciated.\nCondition category: normal\nnutrient_topic: Beta-glucan research collection; topical membership is not evidence of a direct clinical effect, and each preparation is recorded as its own entity with no family link joining any pair.\nplain_language: The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.\norganism: Human\ntissue_or_cell_type: Leukocytes\nexperimental_model: Flow cytometry with labelled soluble polysaccharides, CR3 and CR4 chimeras, and a panel of domain-specific antibodies\nlimitations: Binding and inhibition rather than function. The highest-affinity ligand measured was not a pure beta-glucan but a mannose-rich zymosan polysaccharide, and the sugar specificity proved broader than beta-glucan alone.\nexposure: Labelled beta-glucans from yeast, mushroom, seaweed and barley, and a 10-kilodalton soluble zymosan polysaccharide\nevidence_span: {\"source_cache\": \"artifacts/glucan-research/8558003.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"00a0fef65e91375066fe9920200032466aec1c0d85bf548d53f64c3d384106b7\", \"start_char\": 0, \"end_char\": 1936, \"text_sha256\": \"00a0fef65e91375066fe9920200032466aec1c0d85bf548d53f64c3d384106b7\"}\n[bg-p8558003] Analysis of the sugar specificity and molecular location of the beta-glucan-binding lectin site of complement receptor type 3 (CD11b/CD18). (1996). https://pubmed.ncbi.nlm.nih.gov/8558003/ DOI: 10.4049/jimmunol.156.3.1235","source_key":"import-10629adf-a816-5b7b-82db-a76bfbb946f2","source_title":"Beta-glucan: a structural family rather than an agent, what decides whether a bound glucan actually signals, the complement route that a cereal and a yeast preparation share, and the unequal human evidence behind each (2026-09-22)","claim_ids":["7cd1b53c-c139-5eb1-956d-2f562ca6bba0"]},{"conflict_id":"9b957712-74e1-5f44-b1e6-72f51f1cff1d","ordinal":1,"label":"Removing the complement receptor entirely did not change how macrophages grabbed yeast particles; blocking the other receptor did.","revision_id":"a53bb794-0a4b-525d-9cf7-22b46a5403b0","start_line":112,"end_line":123,"quote":"### bg-dectin1-not-cr3-binds-zymosan\nNon-opsonic zymosan binding was unaffected by genetic CD11b deficiency or a blocking monoclonal antibody against CR3, demonstrating that CR3 was not the beta-glucan receptor mediating this activity, and using the novel anti-Dectin-1 antibody 2A11 Dectin-1 was shown to be almost exclusively responsible for the beta-glucan-dependent non-opsonic recognition of zymosan by primary macrophages, defining Dectin-1 as the leukocyte beta-glucan receptor first described over 50 years ago and resolving the long-standing controversy regarding the identity of this important molecule.\nCondition category: normal\nnutrient_topic: Beta-glucan research collection; topical membership is not evidence of a direct clinical effect, and each preparation is recorded as its own entity with no family link joining any pair.\nplain_language: Removing the complement receptor entirely did not change how macrophages grabbed yeast particles; blocking the other receptor did.\norganism: Mouse\ntissue_or_cell_type: Primary macrophage\nexperimental_model: Carbohydrate inhibition, CD11b-deficient cells and a new anti-Dectin-1 monoclonal antibody applied to non-opsonic zymosan binding\nlimitations: The ligand is zymosan, which is a mannan-rich particle as well as a glucan one, and the readout is non-opsonic binding rather than every glucan response.\nexposure: Zymosan binding to primary macrophages with specific carbohydrate inhibitors, CD11b deficiency, a blocking anti-CR3 antibody and the novel anti-Dectin-1 antibody 2A11\nevidence_span: {\"source_cache\": \"artifacts/glucan-research/12163569.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"533d8630c3d727db58869724825f47c5241cf9c3159acce359d3bc8b0fdb2a6a\", \"start_char\": 0, \"end_char\": 1365, \"text_sha256\": \"533d8630c3d727db58869724825f47c5241cf9c3159acce359d3bc8b0fdb2a6a\"}\n[bg-p12163569] Dectin-1 is a major beta-glucan receptor on macrophages. (2002). https://pubmed.ncbi.nlm.nih.gov/12163569/ DOI: 10.1084/jem.20020470","source_key":"import-10629adf-a816-5b7b-82db-a76bfbb946f2","source_title":"Beta-glucan: a structural family rather than an agent, what decides whether a bound glucan actually signals, the complement route that a cereal and a yeast preparation share, and the unequal human evidence behind each (2026-09-22)","claim_ids":["c067c7b2-dfbd-5629-a0dc-088c42d034cf"]}]}],"corrections":[],"research":null}