The effects of cocaine on viral replication in immune cells

Previous studies have shown that cocaine is capable of altering a number of macrophage functions. The present study demonstrates that the incubation of murine peritoneal macrophages with cocaine inhibits the replication of mouse hepatitis virus (MHV). Incubation of mouse L929 ceUs with cocaine inhibits both MHV and vesicular stomatitis virus (VSV). Monolayers of thioglycoUate-induced peritoneal macrophages from C57BL/6 mice or L ceUs cultured on 96-weU microtiter plates were incubated with various concentrations of cocaine and subsequently infected with one of the above viruses. Replication of virus, as determined by plaque forming units, was inhibited in a dose dependent manner foUowing incubation with cocaine. This inhibition was also dependent on the length of time ceUs were exposed to cocaine. The antiviral ffect was greatest in cultures exposed to cocaine for at least 48 hours and could be transferred by culture media to fresh cells resulting in a 60%-80% inhibition of virus replication. Results were essentially the same whether or not the cell were dividing (L929) or nondividing (macrophage). The addition of polyclonal antibodies to interferon 6 partiaUy reversed this inhibition, whereas antibodies to either tumor necrosis factor or transforming growth factor 6 did not. Further studies are needed to identify the mechanisms involved; however, preliminary data obtained suggest alterations of intracellular calcium as a possible cause of viral inhibition. These studies underscore the multiple effects of cocaine on many biological systems.