TNF and infection: Gene expression analysis of the pro-inflammatory cytokines IFN-γ, TNF, and IL-12, which have previously been implicated in the immune response to T. gondii [69, 70], showed significant effects of both T. gondii (F1,14 = 311.85, p < 0.001; three-way ANOVA for repeated measures with cytokine as within-subjects factor and T. gondii and H. polygyrus as between-subjects factors) and H. polygyrus (F1, 14 = 11.55, p = 0.004) infection, as well as an interaction of the two pathogens (F1, 14 = 10.77, p = 0.005).