CD4 and infection: We gave RAG KO mice T-bet KO TS-CD4-Tg Th17 cells and polyclonal CD8+ T cells, and infected them with T. cruzi. CD4+ T cells recovered from recipient mice 9 and 101 days after infection confirmed that the transferred T-bet KO Th17 cells were veritable Th17 cells, as they did not produce IFN-γ in vivo, but maintained high levels of IL-17A expression (S7A and S7B Fig).