IFNG and infection: In addition, although enhanced serum levels of IFNγ were observed in R. typhi-infected C57BL/6 RAG1−/− mice on day 3 post infection, IFNγ release was unaltered upon NK cell depletion [33], demonstrating that early IFNγ in these mice does not predominantly derive from NK cells but other cells, e.g. MΦ and innate lymphoid cells.