IFNG and infection: However, after 24 hours of infection, with IFNγ stimulation for the last six hours, while RH(I), Pru(II), and CEP(III) infection all significantly inhibited IRF1 expression compared to uninfected cells, cells pre-infected with a Pru(II) strain had significantly higher IRF1 in their nuclei than cells pre-infected with a RH(I) strain (Fig. 1A, B).