{"id":"c067c7b2-dfbd-5629-a0dc-088c42d034cf","stable_key":"10629adf-a816-5b7b-82db-a76bfbb946f2:bg-dectin1-not-cr3-binds-zymosan","predicate":"enables","statement":"Non-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.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"bc0ea1df-c30d-5d06-add8-ef42931d4eb5","mechanism_event_label":"Removing the complement receptor entirely did not change how macrophages grabbed yeast particles; blocking the other receptor did.","subject":{"id":"117c178c-d74c-5c56-b2d6-d3956ad70c03","slug":"clec7a","display_name":"Dectin-1 / CLEC7A","entity_type_key":"protein"},"object":{"id":"259358db-e7c6-54c8-be08-f67e02998bdc","slug":"nonopsonic-recognition","display_name":"Non-opsonic recognition of a yeast particle","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"bc0ea1df-c30d-5d06-add8-ef42931d4eb5","stable_key":"10629adf-a816-5b7b-82db-a76bfbb946f2:bg-dectin1-not-cr3-binds-zymosan-event","event_type":"biochemical_relationship","label":"Removing the complement receptor entirely did not change how macrophages grabbed yeast particles; blocking the other receptor did.","description":"Non-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.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"f32de9ab-2245-5624-9bc8-9b6fa1cdd43c","slug":"zymosan","display_name":"Zymosan, a beta-glucan and mannan-rich yeast particle","entity_type_key":"chemical_species"},"role":"test_particle","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"a06749c1-3762-5f7b-9de7-5862879dfb30","slug":"itgam","display_name":"Integrin alpha-M / CD11b / ITGAM","entity_type_key":"protein"},"role":"excluded_receptor","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"309b5460-2ec8-5c78-ada2-8637d6991433","slug":"cr3-complex","display_name":"Complement receptor 3 / CD11b-CD18","entity_type_key":"protein_complex"},"role":"excluded_receptor","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"78496a78-f03c-56a0-87ab-6f9aaafba38f","slug":"mannose-receptor","display_name":"The macrophage mannose receptor","entity_type_key":"protein"},"role":"excluded_receptor","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"a15f1036-2f04-5ebc-a9a3-0e8fed521f99","slug":"macrophage","display_name":"Macrophage","entity_type_key":"cell_type"},"role":"host_cell","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""},{"entity":{"id":"117c178c-d74c-5c56-b2d6-d3956ad70c03","slug":"clec7a","display_name":"Dectin-1 / CLEC7A","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":5,"notes":""},{"entity":{"id":"259358db-e7c6-54c8-be08-f67e02998bdc","slug":"nonopsonic-recognition","display_name":"Non-opsonic recognition of a yeast particle","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":6,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"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\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Carbohydrate inhibition, CD11b-deficient cells and a new anti-Dectin-1 monoclonal antibody applied to non-opsonic zymosan binding","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Zymosan binding to primary macrophages with specific carbohydrate inhibitors, CD11b deficiency, a blocking anti-CR3 antibody and the novel anti-Dectin-1 antibody 2A11","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"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.","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":"Mouse","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Removing the complement receptor entirely did not change how macrophages grabbed yeast particles; blocking the other receptor did.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[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","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Primary macrophage","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"bc116f95-f315-5fdf-8374-4765dc0863d7","evidence_kind":"source_excerpt","locator":"Lines 112-123","start_line":112,"end_line":123,"excerpt":"### 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","model_system":"Carbohydrate inhibition, CD11b-deficient cells and a new anti-Dectin-1 monoclonal antibody applied to non-opsonic zymosan binding","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [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","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":"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}