CD4 and infection: There was, however, a pronounced increase in the percentage of both CD3+CD4+ and CD3+CD8α+ T cells that were positive for IFN-γ and TNF in co-infected compared to T. gondii-infected animals (main effect of infection status: F1, 8 = 43.52, p < 0.001; three-way ANOVA for repeated measures with cell type and cytokine as within-subjects factors and infection status as between-subjects factor; post hoc two-sample t tests: all t > 4.13, all p < 0.007; Fig. 4d and e).