PROTECTIVE EFFECT OF LITHIUM ON THE STRESS-INDUCED DEPRESSION OF CELL-MEDIATED-IMMUNITY IN MICE

The effect of lithium chloride (LiCl) administration on the stress-ind uced depression of cell-mediated immunity was studied in mice. Two mod els of stress-induced depression of immunity were used: (1) keeping th e animals at a temperature of 4 degrees C twice for 24 h at a 24-h int erval, and (2) keeping them in the dark for 96 h. Both kinds of stress significantly decreased the reactivity of cell donors in the graft-ve rsus-host (GVH) reaction and recipients in the host-versus-graft (HVG) reaction. Treatment with LiCl of the cell donors in GVH reaction or t he recipients in HVG reaction daily for three weeks before stress appl ication completely abolished the immunosuppressive effect of ''cooling '' stress, but not ''darkness'' stress. The LiCl is thus shown as a po tential immunomodulator protecting mice from some forms of the stress- induced depression of cell-mediated immunity.