CD11b is the most commonly used name for Integrin alpha M (ITGAM). Integrins are heterodimeric integral membrane proteins composed of an alpha chain and a beta chain. ITGAM combines with the beta 2 chain (ITGB2) to form a leukocyte-specific integrin referred to as macrophage receptor 1 ('Mac-1'), or inactivated-C3b (iC3b) receptor 3 ('CR3'). ITGAM/ITGB2 is important in the adherence of neutrophils and monocytes to stimulated endothelium, and also in the phagocytosis of complement coated particles. [taken from NCBI Entrez Gene (Gene ID: 3684)].