The antibody-mediated and delayed type hypersensitivity response of mice exposed to polybrominated biphenyls

Abstract

In order to determine the effect of polybrominated biphenyls (PBB) (FireMaster, BP-6) on the immune response, Balb c female mice were fed diets containing 0, 1, 10, 100, and 1000 ppm PBB. After 30 days the in vivo IgM and IgG primary response of mice fed 1, 10, and 100 ppm PBB was, respectively, about 80, 35, and 15% of control values as determined by the Jerne hemolytic plaque assay. The equal reduction in IgM and IgG plaque-forming cells suggested that PBB affected both B and helper T cells. Conversely, the T-cell-dependent delayed type hypersensitivity reaction to sensitization with dinitrofluorobenzene was normal for mice fed, 1, 10, or 100 ppm PBB for 31 days. Although histopathological evaluation indicated a preferential wasting of the cortex of the thymus in mice exposed to PBB, the plasma corticosterone concentrations were only modestly elevated in mice fed 100 ppm PBB and thus probably did not contribute substantially to the observed loss of immature thymocytes or helper T-cell function. By Day 14 of this experiment, over 60% of the mice fed 1000 ppm PBB were dead. The remainder were athymic and incapable of mounting an antibody-mediated response.