Increased replication of simian immunodeficiency virus in CEM x174 cells by morphine sulfate.

Infection with simian immunodeficiency virus induces cytopathic effects on CEM x174 cells in vitro. Syncytium formation of SIV-infected CEM x174 cells was significantly enhanced in the presence of morphine sulfate, with a concomitant increase in the activity of cellular reverse transcriptase and in the expression of SIV p27 core antigen. Parallel establishment of the viability of the morphine-treated cells indicates that the short-acting opioid protects against cell lysis induced by SIV so that replication and production of SIV particles continued and exceeded those without morphine treatment. This delayed cell lysis induced by morphine as seen in vitro correlated with an in vivo observation that peripheral blood mononuclear cells isolated from morphine-treated rhesus macaques displayed a less degree of programmed cell death by apoptosis during early stages of SIVmac infection. These studies suggest that the modification of the biological properties of HIV-infected cells by morphine sulfate may be one of the mechanisms by which opioids exacerbate the progression of HIV in drug abusers.