TNF and infection: In contrast, regarding the CD8+ T cell population, there was little difference in the frequency of the multifunctional T cell population among the M. kansasii-ATCC-, M. kansasii-SM-1-, and BCG-immunized groups in the lung and spleen, but rather higher levels of IFN-γ+TNF-α+ and TNF-α+ populations were detected in lung cells of infection control group (Fig. S5).