CD4 and infection: To test for differences in CD4+ T cell activation and function in response to infection between adult and young mice, we infected 8‐weeks‐old adult or 14‐day‐old pups with 106P. chabaudi iRBCs, and determined effector T cell activation and numbers on day 8 and 14 p.i. using the gating strategy as shown in Figure 3A.