Apoptotic UV-irradiated lymphocytes undergo protease mediated shedding of L-selectin in vitro

Adhesion between circulating lymphocytes and endothelial cells of the Vesse l wall depends on the expression of selectins and is the first step of tiss ue invasion which characterises inflammation. UV-B is well known to induce apoptosis in lymphocytes. We show that induction of apoptosis by any proced ure leads to a metalloprotease mediated shedding of L-selectin from the sur face of T-lymphocytes. Together with the previously published immunosuppres sive action of apoptotic cells, this may contribute to the clinical effect of UV-B application, especially in photopheresis. (C) 2001 Published by Els evier Science Ltd.