Effects of chronic dextromethorphan administration on the cellular immune responses in mice

We examined the chronic effect of dextromethorphan (DM) on the cellular immune responses in mice. T cell stimulator, phytohemagglutinin did not show significant effect on lymphocyte proliferation. Costimulator of T and B cell, pokeweed mitogen, and B cell stimulator, lipopolysaccharide exhibited DM-induced decreased lymphocyte proliferation. Significantly suppressed natural killer (NK) cell cytotoxicity was evidenced following 6 months DM exposure. These results suggest that chronic DM administration perturb B cell functioning and NK cell cytotoxicity. In addition, prenatal DM exposure did not potentiate the immunomodulation in postnatal effect induced by chronic DM.