Emerging contaminants in the marine environment: An in vitro study of the immunotoxicological effects of DE-71, a commercial polybrominated diphenylether mixture, and perfluorooctane sulfonate on dolphin and murine immune cells
Fair, Patricia A
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The effects of emerging contaminants on the immune system of mammals are poorly understood, with limited information available about the immunotoxicological effects of perfluorooctane sulfonate (PFOS) and DE-71, a polybrominated diphenyl ether (PBDE) mixture, at environmentally relevant exposures. Due to challenges of working with dolphins, this study assessed the effects of <italic> in vitro</italic> exposures of PFOS and DE-71 on immune functions in dolphins and mice to determine the predictability of <italic>in vitro</italic> effects to <italic>in vivo</italic> observations as part of a parallelogram approach to assessing risk. Bottlenose dolphin peripheral blood leukocytes and B6C3F1 mouse splenocytes were exposed in culture to PFOS at 0, 0.01, 0.05, 0.1, 0.5, 1.0 or 5.0 μg/mL concentrations or DE-71 at 0, 0.025, 0.05, 0.25, 0.5, 2.5, 5.0, 25 or 50 μg/mL concentrations. The immune endpoints assessed were natural killer (NK) cell activity and lymphocyte proliferation. PFOS significantly decreased NK cell activity at 0.01, 0.05, 0.1, 0.5, and 1.0 μg/mL concentrations in mouse splenocytes, but did not significantly alter dolphin NK cell activity. Mitogen-induced T cell proliferation was significantly decreased in murine cells beginning at the 0.05 μg/mL treatment, but not in dolphin cells. B cell proliferation was not statistically altered by PFOS exposure in either dolphins or mice. DE-71 <italic>in vitro</italic> exposure did not significantly alter NK cell activity or lymphocyte proliferation in dolphins. It also did not alter lymphocyte proliferation in mice, but did augment NK cell activity beginning with the 0.05 μg/mL treatment. Using these <italic>in vitro</italic> models and previous studies on <italic>in vivo</italic> models, the parallelogram approach was able to estimate potential effects of PBDE and PFOS in free-ranging bottlenose dolphin immune function.