Humoral immunity in aged mice exposed to cadmium.

Twelve month old female BDF1 mice were exposed to cadmium chloride in the drinking water at concentrations ranging from 0 to 50 micrograms/mL cadmium for 26 days. The humoral immune response against sheep red blood cells, a T-lymphocyte dependent response, was evaluated during the last five days of the exposure period. The antibody response was not suppressed by cadmium exposure (P = 0.661). Weight gains (P = 0.205) and water consumption (P = 0.378) during the exposure period were also unaffected. These results indicate that the immunosuppressive effects of cadmium which have been documented in younger, more immunologically competent mice were masked by the natural age-related immunosuppression that was observed in this study. Immunotoxicological investigations in aged animal models appear to be a poor indicator of immune dysfunction in the general population.