Cytotoxic activity of monocytes against Toxoplasma gondii in acute, chronic and reactivated murine toxoplasmosis.

The phagocytic activity and cytotoxicity of peripheral blood monocytes (against toxoplasma tachyzoites) was studied in acute, chronic and reactivated toxoplasma infected Swiss albino mice. During acute infection, a low phagocytic activity was observed on the 4th day post infection (dpi) (P less than 0.01) and a low monocyte cytotoxicity was noticed after the 2nd dpi (P less than 0.01) which further decreased till the 8th dpi. In contrast, both the parameters were significantly increased during chronic infection. Increase in monocytic cytotoxicity was manifested on the 3rd dpi (P less than 0.001) whereas phagocytosis showed an increase on the 12th dpi (P less than 0.05). The reactivated group showed no change in both the parameters when compared with the control immunosuppressed group (P greater than 0.05).