Integrin alpha-M / CD11b / ITGAM

Where it participates (unsigned role)

1. 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.

   The lectin site of CD11b C-terminal to the I-domain → Beta-glucan source_derived_draftungraded
   Experimental context and source evidence

   evidence_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"}

   experimental_model

   Flow cytometry with labelled soluble polysaccharides, CR3 and CR4 chimeras, and a panel of domain-specific antibodies

   exposure

   Labelled beta-glucans from yeast, mushroom, seaweed and barley, and a 10-kilodalton soluble zymosan polysaccharide

   limitations

   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.

   nutrient_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. · Beta-glucan

   organism

   Human

   plain_language

   The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment.

   primary_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

   tissue_or_cell_type

   Leukocytes

   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) · lines 203–214

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Flow cytometry with labelled soluble polysaccharides, CR3 and CR4 chimeras, and a panel of domain-specific antibodies · source_derived_draft · unverified_draft

   ### bg-cr3-has-a-lectin-site 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. Condition category: normal nutrient_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. plain_language: The complement receptor grips sugars at a second site, separate from the one that grips the complement fragment. organism: Human tissue_or_cell_type: Leukocytes experimental_model: Flow cytometry with labelled soluble polysaccharides, CR3 and CR4 chimeras, and a panel of domain-specific antibodies limitations: 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. exposure: Labelled beta-glucans from yeast, mushroom, seaweed and barley, and a 10-kilodalton soluble zymosan polysaccharide evidence_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"} [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

   Complete structured claim and evidence

2. 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.

   Dectin-1 / CLEC7A → Non-opsonic recognition of a yeast particle source_derived_draftungraded
   Experimental context and source evidence

   evidence_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"}

   experimental_model

   Carbohydrate inhibition, CD11b-deficient cells and a new anti-Dectin-1 monoclonal antibody applied to non-opsonic zymosan binding

   exposure

   Zymosan binding to primary macrophages with specific carbohydrate inhibitors, CD11b deficiency, a blocking anti-CR3 antibody and the novel anti-Dectin-1 antibody 2A11

   limitations

   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.

   nutrient_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. · Beta-glucan

   organism

   Mouse

   plain_language

   Removing the complement receptor entirely did not change how macrophages grabbed yeast particles; blocking the other receptor did.

   primary_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

   tissue_or_cell_type

   Primary macrophage

   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) · lines 112–123

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Carbohydrate inhibition, CD11b-deficient cells and a new anti-Dectin-1 monoclonal antibody applied to non-opsonic zymosan binding · source_derived_draft · unverified_draft

   ### bg-dectin1-not-cr3-binds-zymosan 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. Condition category: normal nutrient_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. plain_language: Removing the complement receptor entirely did not change how macrophages grabbed yeast particles; blocking the other receptor did. organism: Mouse tissue_or_cell_type: Primary macrophage experimental_model: Carbohydrate inhibition, CD11b-deficient cells and a new anti-Dectin-1 monoclonal antibody applied to non-opsonic zymosan binding limitations: 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. exposure: Zymosan binding to primary macrophages with specific carbohydrate inhibitors, CD11b deficiency, a blocking anti-CR3 antibody and the novel anti-Dectin-1 antibody 2A11 evidence_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"} [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

   Complete structured claim and evidence