The effect of cadmium chloride on the immune response in mice.

Six week old BDF1 female mice were exposed to cadmium chloride in the drinking water at concentrations ranging from 0 to 50 micrograms/mL cadmium for three weeks. The humoral immune response against sheep red blood cells which is T-lymphocyte and macrophage dependent, was suppressed in a dose dependent fashion with the maximum suppression of 28.2% observed in the highest exposure group (P less than 0.0001). Mitogen studies demonstrated that cadmium was a weak mitogen, producing a dose-dependent enhancement of blastogenesis (P = 0.026). T-lymphocyte responses which were induced by concanavalin A were not affected by cadmium exposure (P = 0.284). A dose-dependent enhancement of the B-lymphocyte activity was produced in the presence of cadmium when the lymphocytes were induced with Escherichia coli, lipopolysaccharide, a B-lymphocyte mitogen (P = 0.007). These results suggest that the immunosuppressive effects of cadmium associated with the humoral immune response are not due to an impairment of lymphocyte proliferation, an intermediate step involved in the generation of an immune response. The immunosuppressive effects were produced at relatively low cadmium exposures as indicated by the renal cadmium concentrations suggesting that the immune systems is very vulnerable to the toxic effects of cadmium.