Expression of CD10 by human T cells that undergo apoptosis both in vitro and in vivo

This study shows that human postthymic T cells express CD10 when undergoing apoptosis, irrespective of the signal responsible for initiating the apopt otic process. Cells from continuous T-cell lines did not normally express C D10, but became CD10(+) when induced into apoptosis by human immunodeficien cy virus (HIV) infection and exposure to CD95 monoclonal antibody, etoposid e, or staurosporin. Inhibitors of caspases blocked apoptosis and CD10 expre ssion. Both CD4(+) and CD8(+) T cells purified from normal peripheral blood expressed CD10 on apoptotic induction. CD10 was newly synthesized by the a poptosing cells because its expression was inhibited by exposure to cyclohe ximide and CD10 mRNA became detectable by reverse transcription-polymerase chain reaction in T cells cultured under conditions favoring apoptosis. To show CD10 on T cells apoptosing in vivo, lymph node and peripheral blood T cells from HIV+ subjects were used. These suspensions were composed of a su bstantial, although variable, proportion of apoptosing T cells that consist ently expressed CD10. In contrast, CD10(+) as well as spontaneously apoptos ing T cells were virtually absent in peripheral blood from normal individua ls. Collectively, these observations indicate that CD10 may represent a rel iable marker for identifying and isolating apoptosing T cells in vitro and ex vivo and possibly suggest novel functions for surface CD10 in the apopto tic process of lymphoid cells. (C) 1999 by The American Society of Hematolo gy.