Cocaine augments proliferation of human peripheral blood T-lymphocytes activated with anti-CD3 antibody

Abstract

Previously we observed that cocaine can suppress the phytohemagglutinin-induced proliferation of cultured, purified human T-lymphocytes. However, because the receptor activation pathways stimulated by this mitogen are not fully understood, we decided in the present study to examine the effects of cocaine on T-lymphocyte cultures stimulated with the anti-CD3 antibody which is known to stimulate these cells through the T-cell receptor complex. The results show that cocaine augments T-lymphocyte proliferation to anti-CD3 stimulation at drug concentrations observed in the blood of cocaine abusers. This augmentation was dose dependent reaching a plateau at a concentration above 0.75 μM. The amount of interleukin-2 (IL-2), as measured by ELISA, in the supernatants of T-cell cultures and the level of cytosolic free-calcium (Ca 2+) mobilization in the T-cells were also increased at approximately the same concentrations that increased proliferation. Cocaine treatment alone had no effects on proliferation, IL-2 production, or Ca 2+ mobilization. These results suggest that cocaine augments proliferation of human T-lymphocytes when the cells are activated thorugh the T-cell receptor complex by increasing cytosolic Ca 2+ mobilization and subsequent IL-2 production.