Intercellular adhesion molecule 1 (ICAM-1) – Lymphocyte function-associated antigen 1 (LFA-1) interaction (ICAM-1 – LFA-1 interaction)

The Intercellular adhesion molecule 1 (ICAM-1) – Lymphocyte function-associated antigen 1 (LFA-1) interaction is a fundamental protein-protein interaction (PPI) that governs leukocyte trafficking and immune cell activation [1, 2]. ICAM-1 (CD54) is a transmembrane glycoprotein of the immunoglobulin superfamily expressed on endothelial and epithelial cells, while LFA-1 (integrin alpha-L beta-2) is a heterodimeric integrin found on the surface of all leukocytes [4, 5]. This interaction is a prerequisite for the firm adhesion of leukocytes to the vascular endothelium and their subsequent extravasation into inflamed tissues [5, 6]. Additionally, the ICAM-1/LFA-1 complex acts as a critical co-stimulatory signal (Signal 2) within the immunological synapse, promoting T-cell activation, proliferation, and the release of pro-inflammatory cytokines [1, 10]. Pathological upregulation of this pathway is a hallmark of chronic inflammatory and autoimmune conditions, including dry eye disease, psoriasis, and rheumatoid arthritis [4, 7]. Therapeutic strategies targeting this interaction, such as the small molecule antagonist lifitegrast, work by competitively inhibiting the binding of LFA-1 to ICAM-1, thereby disrupting the cycle of inflammation [3, 9].

Other names

ICAM-1/LFA-1 complexCD54/CD11a-CD18 interactionICAM-1/LFA-1 adhesionLFA-1/ICAM-1 co-stimulatory interactionIntegrin alpha-L beta-2/ICAM-1 interaction

Competitive antagonism of LFA-1 to block its binding with ICAM-1, thereby inhibiting T-cell adhesion, migration, and co-stimulatory activation.