Neurotoxicity and immunotoxicity assessment in CBA/J mice with chronic Toxoplasma gondii infection and multiple oral exposures to methylmercury

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American Society of Parasitology

The present study was conducted to determine the effect of multiple low doses of methylmercury (MeHg) on the course of a chronic Toxoplasma gondii infection. Four groups of 6-wk-old female CBA/J mice either were fed 25 T gondii tissue cysts of the ME-49 strain or were vehicle control. Six weeks later, half of each group was orally gavaged with 8-mg/kg body weight doses of MeHg on days 0, 2, 4, 7, 10, and 13, totaling 4 experimental groups. Mice were killed on day 17 or 18 after MeHg exposure. Flow cytometric analysis of lymphocyte subpopulations in the thymus demonstrated a significant increase in the percentage of CD4(-)CD8(+) T-cells in mice exposed to MeHg with a concurrent T gondii infection. Groups of mice exposed to MeHg showed a decrease in total thymic cellularity and cellularity of all T-cell subpopulations when compared with control mice, but viability of these cells was unaffected. Splenic cell viability was decreased in mice exposed to MeHg, but alterations in T-cell subpopulations were not noted. These data indicate that multiple low doses of MeHg may not exacerbate chronic toxoplasmosis, but MeHg-induced effects on the immune system were evident.

expression, sites, brain, parasitology
Marquea D. King, David S. Lindsay, S. Holladay, and M. Ehrich (2003). "Neurotoxicity and Immunotoxicity Assessment in CBA/J Mice with Chronic Toxoplasma gondii Infection and Multiple Oral Exposures to Methylmercury," Journal of Parasitology, Vol. 89, No. 4, pp. 856-859. doi: