Integrin beta-2 subunit (CD18)

The **Integrin beta-2 subunit (CD18)** is a transmembrane glycoprotein encoded by the ITGB2 gene and widely recognized as a key component of several leukocyte integrins, including LFA-1 (with CD11a), Mac-1 (with CD11b), p150,95 (with CD11c), and α_Dβ_2 (with CD11d)[6][7][8][9]. These integrin heterodimers are essential receptors on leukocytes, facilitating cell-cell adhesion, migration through the endothelium (extravasation), and immune synapse formation[3][5]. CD18 enables leukocytes to adhere to and translocate across activated endothelium at sites of inflammation, as well as participate in phagocytosis and immune synapse stability in T cells and NK cells[5][8]. Genetic deficiency of integrin beta-2 causes leukocyte adhesion deficiency type 1, resulting in severe, recurrent infections and impaired immune function[3]. CD18 forms the beta chain of the integrin heterodimers with a structure supporting both resting and active conformations, regulating its adhesive properties in response to cell signaling[2][4]. CD18/β2 integrins serve as principal receptors for intercellular adhesion molecules (ICAMs) and complement fragments (e.g., iC3b), underlining their versatility in both innate and adaptive immune responses[5][6][8]. Therapeutic targeting of CD18 or its interactions holds potential but is associated with risks of immunosuppression and heightened susceptibility to infections.

Other names

CD18ITGB2Integrin beta chain-2Leukocyte function-associated antigen-1 beta subunit (LFA-1 beta subunit)Complement receptor 3 and 4 subunitIntegrin subunit beta 2

Blocking leukocyte adhesion to vascular endothelium (by inhibiting integrin-ligand binding) Inhibiting leukocyte migration Modulation of immune synapse formation and activity