INHIBITION OF CD26 ENZYME-ACTIVITY WITH PRO-BOROPRO STIMULATES RAT GRANULOCYTE-MACROPHAGE COLONY FORMATION AND THYMOCYTE PROLIFERATION IN-VITRO

CD26 dipeptidyl peptidase (DPPIV) is involved in the regulation of proliferation of some hematopoietic and T-lineage cells. Here, we show that Pro-boropro a potent inhibitor of DPP activity has a costimulating effect in hematopoietic colony assays for macrophage and, to a lesser extent, for granulocyte colonies and has a stimulating effect in organ cultures of immature thymocytes. Based on these and other evidences, we propose that the mechanism by which CD26 regulates proliferation is associated with its DPP activity. (C) 1995 by The American Society of Hematology.