DIPEPTIDYL PEPTIDASE-IV (CD26) ON HUMAN-LYMPHOCYTES - SYNTHETIC INHIBITORS OF AND ANTIBODIES AGAINST DIPEPTIDYL PEPTIDASE-IV SUPPRESS THE PROLIFERATION OF POKEWEED MITOGEN-STIMULATED PERIPHERAL-BLOOD MONONUCLEAR-CELLS, AND IL-2 AND IL-6 PRODUCTION

In the present report, we describe that synthetic inhibitors of and po lyclonal and monoclonal antibodies against the membrane ectoenzyme dip eptidyl peptidase IV (DP IV, CD26) inhibit the production of IL-2 and IL-6 and, concomitantly, DNA synthesis of pokeweed mitogen-stimulated peripheral blood mononuclear cells (PBMC). The release of IL-1 and TNF -alpha, was not influenced under these conditions. The data support th e hypothesis that DP IV, possibly in conjunction with other peptidases , is involved in the regulation of activation and proliferation of T l ymphocytes.