Integrins play a central role in mediating lymphocyte adhesion to a number of surfaces. Integrin alphaLbeta2 (LFA-1) interacts with Intercellular adhesion molecule (ICAM)1-5, which are typically expressed on other immune system cells. ICAM4 and 5 are known to be expressed on telencepahlic neurons.
VCAM-1 regulates lymphocyte adhesion to activated endothelial cells via Very Late Antigen-4 (VLA-4). To function in a circulating mode, leukocytes express LFA-1 and VLA-4 in a low ligand binding capacity. When leukocytes reach sites of imflammation, these integrins are switched to a higher binding state to guide the complex process of transmigration, tethering, rolling, arrest, adhesion and shape change. Signal cascades between LFA-1 and VLA-4 may cross-talk affecting binding affinities in a reciprocal fashion.