Importantly, compared to WT CD4 T cells, ifnar1-/- CD4 T cells responding to malaria also exhibited a 30% decrease in the co-expression of T-bet and Blimp-1, demonstrating that CD4 T cell-intrinsic IFNAR signaling directly induces transcription factors important for Tr1 function. The gene discussed is PRDM1; the disease is malaria.