TNF and infection: Immunohistological analysis of lung tissues revealed that the levels of IFN-γ and TNF-α, which are representative Th1 cytokines, were significantly higher in the BCGΔRS01790 infection group than in the WT BCG and cBCGΔRS01790::RS01790 infection groups at 4 and 8 dpi, and they were significantly lower after 16 dpi (Figures 8A, B).