Toxoplasma gondii: kinetics of lymphocyte subsets in blood and spleen of perorally infected mice.

The blood and spleen lymphocyte subsets and parasite burdens in blood, lungs, and brain were determined serially in C57B1/6 mice infected with an avirulent strain of Toxoplasma gondii. Five mice were sacrificed at various time points after infection; Thy1-2+, Ly5+, CD4+, CD8+, and Ly6c+ lymphocyte subsets and macrophages were determined in blood and spleen by cytofluorometry and parasite burdens were quantified in blood, lungs, and brain by means of a tissue culture method. In infected mice, a large increase in the percentage of CD8+ lymphocytes in blood was observed from Day 14, peaking at Day 21; the percentage of CD4+ lymphocytes was not significantly modified compared with uninfected controls.