Using primed spleen cells, Yang et al. [20] have shown further that the levels of IFN-γ, TNF, and IL-12 were decreased when exogenous IL-10 was added to Chlamydia-infected C57BL/6 IL-10 knockout mice, indicating that IL-10 reduces the levels of cytokines produced during the infection process in the lung model. This evidence concerns the gene IFNG and infection.