CD4 and infection: As observed for CD4+ T cells in the infection of BALB/c IFNγ-/- mice with R. typhi, the infection of C57BL/6 IFNγ-/- mice with E. falciformis was also associated with increased production of IL-17A and IL-22 by CD4+ T cells, and the authors further show that the neutralization of both IL-22 and IL-17A or IL-22 alone in C57BL/6 IFNγR-/- mice leads to increased parasite load in vivo [77], indicating a dominant protective effect of IL-22 in this infection.