Integrin subunit alpha M beta 2 (Mac-1)

Integrin subunit alpha M beta 2, also known as Mac-1 or CD11b/CD18, is a heterodimeric transmembrane receptor primarily expressed on myeloid cells such as neutrophils, monocytes, and macrophages [1, 3]. It belongs to the beta-2 integrin family and plays a central role in the innate immune system by mediating leukocyte adhesion to the vascular endothelium and subsequent migration into tissues [2, 18]. Beyond its role in trafficking, it serves as a complement receptor (CR3) that recognizes iC3b-coated pathogens, facilitating their phagocytosis and destruction [5, 8]. In disease contexts, dysregulation of alpha M beta 2 is linked to chronic inflammatory conditions, autoimmune disorders like systemic lupus erythematosus, and cardiovascular diseases such as atherosclerosis [1, 4, 10]. Therapeutic strategies include both antagonists to dampen excessive inflammation and agonists to enhance anti-tumor immunity or paradoxically inhibit migration by promoting hyper-adhesion [3, 11]. However, targeting this receptor carries risks of immunosuppression and impaired host defense against infections [5, 9].

Other names

Mac-1CD11b/CD18Complement receptor 3CR3ITGAM/ITGB2Macrophage-1 antigenCD11bCD18CR3AMAC1AMO1A

Inhibition of leukocyte recruitment via blockade of ligand binding [1]; Allosteric agonism to stabilize active conformation and promote hyper-adhesion or enhance phagocytosis [3, 11].