Integrin αMβ2 (αMβ2)

Integrin αMβ2 (Mac-1, CR3) is a leukocyte-specific receptor found on monocytes, macrophages, neutrophils, dendritic cells, and some lymphocytes. It consists of two subunits, αM (ITGAM/CD11b) and β2 (ITGB2/CD18), forming a heterodimer that mediates cell-to-cell and cell-to-matrix interactions essential for immune responses. αMβ2’s extracellular domains bind multiple ligands, including inactivated complement (iC3b), fibrinogen, and adhesion molecules on the endothelium, facilitating immune cell recruitment and phagocytosis. It is involved in the pathogenesis of several inflammatory and autoimmune diseases, notably systemic lupus erythematosus, through genetic associations. Therapies targeting αMβ2 are under investigation for their ability to reduce inappropriate immune activation, although modulation risks suppressing host defenses.

Other names

Macrophage-1 antigen (Mac-1)Complement receptor 3 (CR3)CD11b/CD18ITGAM/ITGB2CR3ACluster of differentiation molecule 11B (CD11B)Leukocyte beta-2 integrin

Inhibition of leukocyte adhesion and migration (blockade of integrin interactions); Blockade of phagocytosis (e.g. antibodies occupy ligand binding sites); Inhibition of complement binding (preventing iC3b interaction); Prevention of immune synapse stabilization (inhibition of cell-cell interactions).