[Adhesion molecules of Leu-CAMs leukocytes]

Adhesion molecules of leucocytes Leu-CAMs, also called beta-2 integrins, are heterodimeric glycoproteins which play a crucial role in interactions of leucocytes between themselves or with fundamental intercellular substances. They comprise 3 elements: LFA-1 (CD11a/CD18) expressed at the surface of leucocytes, and in particular lymphocytes, M01 or MAC-1 (CD11b/CD18), and p 150.95 (CD11c/CD18) expressed only on granulocytes, monocytes and macrophages. Their structure, function and regulation are studied. These 3 elements differ in the ligand(s) to which they adhere. LFA-1 intervenes in the adhesion of lymphocytes T and B and of cells presenting with the APC antigen; it therefore plays an important role in lymphoblast proliferation, T-cell cytotoxicity and immunoglobulin synthesis. M01 and p 150.95 intervene in the adhesion of particles and germs opsonized by serum complement, thereby playing a fundamental role in the body's defence against bacterial and fungal infections. They also intervene in the adhesion of leucocytes onto the vascular endothelium and in their migration through this vascular wall towards the inflammatory focus. The pathologies related to a congenital deficiency of these adhesion molecules or to the alterations they acquired are dealt with. The use of monoclonal antibodies directed against leucocyte adhesion in animal experiments opens new therapeutic vistas.