Abstract: This study investigated in vitro the effects of methylmercury chloride (CH3HgCl), zinc chloride (ZnCl2), cadmium chloride (CdCl2), lead acetate (Pb(C2H3O2)2), and PCBs (Aroclor mixtures) on the proliferation of T lymphocytes from the thymus, lymph node, and blood from one female grey seal (Halichoerus grypus) juvenile. After exposure to heavy metals, a dose-response curve was observed with a decrease in proliferation of both T lymphocytes from blood and the lymph node. Exposure to Aroclor mixtures led to a mostly reduced proliferation of thymocytes and T lymphocytes from the lymph node and blood. Lymph node cells seem less sensitive to heavy metals than peripheral blood lymphocytes. Lymph node lymphocytes are more sensitive to PCBs than peripheral blood lymphocytes but less than thymocytes. These results suggest that the sensitivity of T lymphocytes from one grey seal to contaminants may be due to inherent tissue/matrix differences in the sensitivity of these cells to contaminants; however, an individual response cannot be excluded in the present case. That is, samples from a single individual are not extrapolated to the species as a whole in this paper but discussed relative to exposure response by tissues.

Key Words: heavy metals, PCBs, grey seal, Halichoerus grypus, T lymphocytes, peripheral blood, immunotoxicity, thymus, lymph node

Document Type: Research article

DOI: 10.1578/AM.36.4.2010.365

Page Numbers: 365-371

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