Immunopathology of cadmium in bovine calves

Immunopathological effects of cadmium was studied in 6 crossbred male bovine calves vaccinated with Brucella abortus strain 19 vaccine. These calves were divided into two groups of 3 each. Group I calves were kept as control while group II calves were given cadmium 10 mg/kg b.w. in drinking water for a period of 4 months. Blood and serum samples were collected at 15 day intervals for detennination of humoral and cell-mediated immune response. Humoral immunity was detennined by assessing the Brucella specific antibody titres, total IgG and total IgM titres and B-Iymphocyte blastogenesis assay using lipopolysaccharide as mitogen. The cell mediated immunity was assessed by lymphocyte stimulation assay of peripheral blood using phytohaemagglutinin-M (PHA-M) as mitogen and by enumeration of BoCD₄⁺ and BoCD₈⁺ cells in peripheral blood. The results showed that the blastogenic activity of T-Iymphocytes reduced significantly in cadmium fed calves in comparison to controls. There was significant reduction in BoCD₄⁺ (T-helper cells) and BoCD₈⁺ (T-cytotoxic cells), brucella specific antibody titres, total IgG and IgM levels in cadmium fed calves in comparison to controls. Cadmium, thus, was found to have immunosuppressive effect at a dose of 10 mg/kg b.w. which may lead to increased susceptibility of animals to various diseases.