Date of Award


Degree Type


University or Center

Atlanta University (AU)


School of Arts and Sciences

Degree Name




First Advisor

Dr. Judith R. Lumb

Second Advisor

Dr. Louise T. Miller-Stevens


Non-specific cytotoxicity, mediated by Toxoplasma gondii activated macrophages for the F1 and F10 B16 melanoma cells in vitro, was examined in this study. In vitro cytotoxicity was assayed by measuring the release of tritiated thymidine from pre-labeled tumor cells during twenty four-hour and seventy-two hour assay periods. Pre-labeled cells were incubated with peritoneal macrophages obtained from either uninfected C57BL mice used as controls or mice latently infected with the C56 strain of Toxoplasma gondii. There were significant differences observed in the total percent of tritiated thymidine released spontaneously by the F1 and F10 B16 melanoma cells compared to F1 and F10 melanoma cells incubated with macrophages obtained from either latently infected mice or uninfected mice during both assay periods used. There was no significant difference in the percent tritiated thymidine released by the F1 and F10 melanoma cells incubated with normal macrophages, compared to melanoma cells incubated with macrophages obtained from latently infected mice. When lysozyme activity was measured as an index of macrophage activation, the extracts of macrophages derived from mice with latent infection showed evidence of greater lysozyme activity than the extracts of macrophages obtained from uninfected mice. There is evidence in this study to show that although infection with Toxoplasma gondii did confer increased activation on macrophages, this degree of activation was not sufficient enough to demonstrate enhanced cytotoxic effect of the macrophages on the F1 and. F10 Bl6 melanoma tumor cells, under the conditions of the assays used in this study.

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