IFNG and infection: Encouragingly, we found that the fpt mutants induced similarly elevated levels of IFN-γ and TNF-α in the BALF as LVS, which may contribute to the development of protective immune responses in fpt mutant-infected mice that are not seen in the LVS-infected mice that succumb by day 10 post-infection, which is not sufficient time for the development of the adaptive response.