CD4 and infection: Interestingly, a recent study suggests that Th cell-derived IFN-γ contributes to protection in a murine model of malaria, not by affecting the quantity but the quality of the adaptive immune response, as ablation of IFN-γ in CD4 T cells specifically resulted in deficient IgG2c isotype switch and diminished control of the parasite during the chronic stage of infection (45).