Role of corticosteroids in cadmium induced immunotoxicity

Cadmium chloride at doses of 30, 100 and 300 ppm was orally fed to swiss albino mice for 35 days and the humoral and cell mediated immunity was studied by measuring the haemagglutination titre and delayed type hypersensitivity response respectively. Further, the blood corticosteroid level was determined in all the groups. Cadmium at doses of 100 and 300 ppm was found to significantly (p < 0.05) suppress both humoral and cellular immunity with simultaneous increase in the level of blood corticosterone and aldosterone. In order to assess whether the suppression of immune response in cadmium exposed mice is mediated by corticosteroids, aminoglutethemide, an adrenal blocker was administered to mice along with cadmium and the immune response was studied. Aminoglutethemide when administered alone caused significant (p < 0.05) stimulation of immunoglobulin level and delayed type hypersensitivity response as compared to cadmium (300 ppm) fed mice. When co-administered with cadmium, the cadmium induced immunosuppression was reversed back to normal. The results of this study indicate the involvement of adrenal hormones in cadmium induced immunosuppression suggesting that cadmium activates the corticosteroid associated immunoregulatory circuit.