IFNG and infection: In order to rule out the possibility of a defect in IFN-γ-mediated recruitment of an effector population in CD4-depleted IFN-γ−/− mice, IFN-γ−/− and μMT control mice were depleted of CD4+ T cells during primary infection (as shown in Fig. 1) and levels of immune cell populations present in the genital tract were determined by flow cytometry.