Selective effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and corticosteroid on in vitro lymphocyte maturation.

摘要: The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the corticosteroid dexamethasone have potent effects on lymphocyte function, although of former not been well characterized. In present studies murine B cell maturation was used as a model system to examine compare TCDD function. Immunosuppression by is mediated binding specific intracellular R referred Ah glucocorticoid R, respectively. Although both compounds were comparable in their ability inhibit antibody responses T-independent antigen TNP-LPS, events responsible for suppression found be distinct. Dexamethasone, affecting multiple stages maturation, had its primary effect very early, manifested inhibition phosphoinositide signal transduction pathway. This evidenced decrease accumulation inositol phosphate surface Ia expression an inability enter cycle after stimulation with anti-Ig. contrast, neither early signaling nor proliferation affected cells treated TCDD. However, inhibited Ig secretion T cell-replacing factor, suggesting that modulates differentiation into plasma cells. These differential results confirmed monitoring antigens occur cells, including Ia, 7D4, PC.2, during this maturational process. Whereas (Ia 7D4), blocked only marker PC.2. altered later cycle, presence required at time initial activation effective, may interfere programming.