Enhancement by IL-1β and IFN-γ of platelet activation: Adhesion to leukocytes via GMP-140 / padgem protein (CD62)

Abstract We have examined the effect of inflammatory cytokines on the platelet activation. IL-1β and IFN-γ were found to enhance the adhesion of thrombin-treated platelets to monocytic leukemia cells (U937), when the adhesion was assayed by platelet-mediated cell agglutination. The agglutination was inhibited by a monoclonal anti-GMP140 antibody or EDTA, suggesting that the enhanced platelet adhesion to the leukemic cells was mediated by GMP140. In addition, these cytokines also increased the release of 5-HT from platelets in the presence of a low concentration of thrombin. These data suggest that platelet functions are regulated by the cytokines and that activated platelets participate in inflammatory process.