IL4 and infection: Since a transient IL-4-producing population has been observed early during infection with L. major in C57BL/6 mice31, we examined effector T cells in the dLNs at 9 d.p.i. However, we did not observe a skewed GATA3+ CD11ahiCD44+ population in Cd4E4mΔ/Δ/ E4aΔ/Δ mice nor an increase in IL-4 levels in the footpads of infected mice (Supplementary Fig. 6d, e).