Lymphocyte function–associated antigen 1 (LFA-1)

Lymphocyte function–associated antigen 1 (LFA-1) is a heterodimeric integrin composed of the αL (CD11a) and β2 (CD18) subunits, predominantly expressed on leucocytes[1][4]. It mediates adhesion by binding to intercellular adhesion molecules (ICAM-1 through ICAM-5 and JAM-A), playing a crucial role in leukocyte trafficking, firm arrest on endothelium, transmigration, and immune synapse formation between T cells and antigen-presenting cells[1][4][5][7][8]. LFA-1 activation is regulated by inside-out and outside-in signaling, with conformational changes in its I-domain controlling ligand affinity[1][4][6]. Therapeutically, it is targeted in diseases characterized by inappropriate or excessive immune cell infiltration, with biologics like efalizumab (withdrawn due to safety) and lifitegrast affecting LFA-1 function[2][5]. Notable challenges include immunosuppression and adverse reactions related to global inhibition of leukocyte adhesion[2].

Other names

CD11a/CD18αLβ2 integrinLeukocyte function-associated molecule 1Integrin alpha-L/beta-2

Inhibition of LFA-1/ICAM-1 interaction, Blockade of leukocyte adhesion and trafficking, Modulation of immune cell activation