To investigate potential direct effects of neutralizing IFN-γ on challenge parasitemia due to persisting antibody and determine the role of persistent IFN-γ induced by MCMV in protection, we examined the effect of anti-IFN-γ clone H22 on P. chabaudi infection with or without an earlier dose of MCMV (S4A Fig). Here, IFNG is linked to parasitic infectious disease.