Integrin alpha L beta 2 (LFA-1)

Integrin alpha L beta 2, commonly known as Lymphocyte function-associated antigen 1 (LFA-1), is a heterodimeric cell surface receptor composed of the alpha L (CD11a, encoded by ITGAL) and beta 2 (CD18, encoded by ITGB2) subunits[1][5][7]. LFA-1 is broadly expressed on leukocytes including T cells, B cells, monocytes, neutrophils, and natural killer cells[1][5][7]. The receptor mediates essential adhesive interactions with intercellular adhesion molecules (ICAM-1, ICAM-2, ICAM-3, and JAM-A) and is involved in stabilizing immune synapses between T cells and antigen-presenting cells, facilitating immune cell migration, and regulating immune cell activation and signaling[1][2][6][7]. Dysfunction or genetic deficiency of the beta 2 subunit leads to leukocyte adhesion deficiency (LAD-1), characterized by impaired immune responses and increased infection susceptibility[1][5]. Therapeutic agents such as the monoclonal antibody efalizumab, previously approved for autoimmune disorders, target LFA-1 to block leukocyte adhesion but may cause significant immunosuppressive side effects, including increased risk for opportunistic infections[7]. LFA-1 has no enzymatic activity but plays a multifaceted role in immune regulation and is a validated therapeutic target in immunology[6][2].

Other names

Lymphocyte function-associated antigen 1LFA-1CD11a/CD18ITGAL/ITGB2Leukocyte function-associated antigen-1αLβ2 integrinIntegrin alpha-L beta-2

Inhibition of leukocyte adhesion; Blockade of costimulatory signaling in T cells; Suppression of immune cell migration