Effects of imipramine on T cell subsets in olfactory bulbectomized mice

To elucidate the immunological outcome in antidepressant therapy, the effects of acute or chronic imipramine (IMP) treatment on T cell subsets were examined in sham-operated (SO) and olfactory bulbectomized (OB) mice. Olfactory bulbectomy decreased the ratio of Lyt2-positive suppressor T cells to L3T4-positive T helper cells. Acute IMP treatment did not exert any effect on the ratio in SO nor in OB mice. Chronic IMP administration was found to significantly increase the ratio in SO and OB mice and, as a result, the ratio was significantly higher in SO mice compared with the control, while the ratio was normalized in OB mice. The present study may be suggestive of the immune activation in depression and of the immunosuppressive effects of antidepressants.