Morphine promotes apoptosis in Jurkat cells

Patients with intravenous heroin addiction are prone to recurrent infections and at times these infections are fatal. We evaluated the effect of morphine on the apoptosis of Jurkat cells and freshly isolated human T lymphocytes. Morphine promoted apoptosis of both the Jurkat cells and the freshly isolated T lymphocytes in a dose‐dependent manner. DAGO, a specific p receptor agonist, also promoted Jurkat cell apoptosis. DNA isolated from morphine‐treated Jurkat cells and T lymphocytes also showed integer multiples of 200 base pairs. Superoxide dismutase (SOD) enhanced lymphocyte apoptosis; whereas catalase attenuated the morphine‐induced apoptosis of Jurkat cells as well as of T lymphocytes. Morphine‐treated Jurkat cells also showed a decreased expression of bcl‐2 and an enhanced expression of bax. In addition, morphine‐treated Jurkat cells showed activation of caspase‐3. These results indicate that morphine‐induced T lymphocyte apoptosis may be mediated through the generation of reactive oxygen species. The change in ratio of bax and bcl‐2 seems to tilt the balance toward apoptosis, leading to the activation of caspase‐3. This study provides further support for the hypothesis that morphine may be directly compromising immune function by enhancing apoptosis of T lymphocytes in patients with heroin addiction. J. Leukoc. Biol. 66: 650–658; 1999.