Anatomy of the lymphocyte function-associated antigen-1

The β2-integrin lymphocyte function-associated antigen-1 (LFA-1, αLβ2, CD11a/CD18) is made of the association of the CD11a and CD18 subunits that each possesses a large extracellular region and short transmembrane and cytoplasmic parts. A general comparison among species enlights the importance of especially conserved functional regions, as well as their role in folding and heterodimerization. This review also focuses on providing insights into structural aspects that lead to lymphocyte function-associated antigen-1 ability, central to its critical role in the molecular interactions responsible for leukocyte adhesion and migration in the immune system, to modulate dynamically its adhesiveness through avidity (affinity and valency)-based mechanisms.