Stimulation of mouse macrophage antigen presentation by cocaine

Cocaine has been demonstrated to have multiple effects on the immune system. Here, we determined the effects of cocaine on macrophage antigen presentation, using an in vitro antigen presentation assay after macrophages were treated with cocaine both in vitro and in vivo. Our results showed that in vitro treatment of macrophages with cocaine significantly enhanced macrophage's ability to present ovalbumin (OVA) and the enhancement was also demonstrated in the macrophages of cocaine-injected mice. The presentation of an OVA-derived antigenic peptide (OVA323-339), however, was not affected. In vitro cocaine treatment neither affected antigen uptake nor major histocompatibility complex (MHC) II expression and the expression of co-stimulatory molecules B7. These results suggest that cocaine may act on an early event in the antigen handling by accessory cells.