This antibody clone VIM12 (clone renamed, formerly Bear-1) reacts with the CD11b alpha chain of the CD11b/CD18 (p165, 95) integrin heterodimer complex present on Human NK cells, monocytes, and granulocytes. The recognized structure is the alpha chain of a heterodimer glycoprotein of Mw 165 kDa (alpha chain) and 95 kDa (beta chain).
CD11b is implicated in various adhesive interactions of monocytes, macrophages and granulocytes as well as in mediating the uptake of complement coated particles. It is identical to CR3, the receptor for the iC3b fragment of the third complement component. It probably recognizes the RGD peptide in C3b. CD11b is also a receptor for fibrinogen, factor X and ICAM1. It recognizes P1 and P2 peptides of fibrinogen gamma chain. The Mac1 CD11b antigen is present on macrophages, granulocytes, natural killer cells, blood monocytes. CD11b is expressed on 8 % spleen cells, 44 % bone marrow cells and less than 1 % of thymocytes and is commonly used as a microglial marker in nervous tissue.Synonyms: CD11 antigen-like family member B, CR-3 alpha chain, CR3A, Cell surface glycoprotein MAC-1 subunit alpha, ITGAM, Integrin alpha-M, Leukocyte adhesion receptor MO1, MAC1, Neutrophil adherence receptor