IFNG and toxoplasmosis: The difference between microbial and peptide restimulation is an important one and we believe that the IFN-γ responses to whole parasite restimulation better reflects the physiological effector function of CTLs in vivo, as it is well documented that IL-12-deficient mice rapidly succumb to toxoplasmosis due to the lack of T cell IFN-γ production [20],[31].