The effects of in vitro exposure of beluga whale splenocytes and thymocytes to different
concentrations of mercury chloride (HgCl2), cadmium chloride (CdC12 and lead chloride
(PbCl2) were evaluated. The cells were cultured for 66 hours with either concanavalin A (Con-A),
phytohemagglutinin (PHA), or without mitogen, after which percentage of cell death and proliferation were evaluated.
Increased percentage of dead cells was observed in Con-A-stimulated thymocytes cultures with HgCl2, while the
viability of splenocytes was not affected by exposure to metals. Decreased sp] endocyte and thymocyte proliferation was
observed with the highest concentration of HgCl2 and CdCl2 (10-5 M), while lower
concentrations of these metals (10-6 and 10-7M) as well as all the different concentrations of
PbC12 (10-4, 10-5 and 10-6 M) did not influence significantly cell
proliferation. Methyl-mercury affected cell proliferation at concentrations 10 times lower than mercury chloride.
Concentrations of metals that were found to affect the proliferation of beluga lymphocytes are similar to those found in
the liver of beluga whales from wild populations.