Integrin alpha-L chain (ITGAL (also known as CD11a))

Integrin alpha-L chain is a subunit of the heterodimeric integrin receptor known as lymphocyte function-associated antigen 1 (LFA‑1), which consists of an alpha-L subunit encoded by the ITGAL gene and a beta2 subunit. This receptor is expressed on all leukocytes. It mediates critical functions in the immune system including cellular adhesion through binding to intercellular adhesion molecules ICAM‑1, ICAM‑2, ICAM‑3, and ICAM‑4 on other cells. These interactions are essential for processes such as extravasation of lymphocytes from blood vessels into tissues during inflammation or infection; formation of immunological synapses between T cells and antigen-presenting cells; cytotoxic activity by natural killer cells; phagocytosis by macrophages; costimulatory signaling required for full activation of lymphocytes; and maintenance/developmental roles in hematopoiesis. Drugs that target this molecule have been developed for autoimmune diseases but may carry significant safety risks due to their impact on normal immunity.

Other names

CD11aLeukocyte function-associated antigen 1 alpha chain (LFA-1A)Leukocyte adhesion glycoprotein LFA-1 alpha chainIntegrin, alpha L (antigen CD11A, p180)Ly-15Ly-21Lymphocyte antigen 15

Antagonists block the interaction between integrin alpha-L/beta2 complex (LFA‑1) and its ligands ICAMs on endothelial or target cells, thereby inhibiting leukocyte adhesion, migration, activation, or costimulation in the immune response.