King, M. D.Lindsay, David S.Holladay, Steven D.Ehrich, Marion F.2014-06-202014-06-202003-08Marquea 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: http://dx.doi.org/10.1645/GE-79R0022-3395http://hdl.handle.net/10919/49060The 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.application/pdfenIn CopyrightexpressionsitesbrainparasitologyArticle - Refereedhttp://www.bioone.org/doi/abs/10.1645/GE-79Rhttps://doi.org/10.1645/ge-79r