IFNG and infection: Furthermore, IRF7 is necessary for control of L. donovani parasites in liver and spleens since hepatic T cells from IRF7–/– mice produced significantly less IFN-γ upon PMA-ionomycin restimulation, and were deficient in NOS production33,34, CD4+ T cells from IRF7–/– mice upon infection with L. donovani parasites produced IFN-γ levels comparable to wild type mice 14- and 28- days post-infection29.