AIFM2 and infection: We found that overexpression of ppsB or amiD gene enhanced intracellular M. tuberculosis growth while knockdown of ppsB or amiD gene dampened intracellular M. tuberculosis growth (Fig. 4, C and D; lower panel), indicating that ppsB and amiD are essential virulence factors of M. tuberculosis although amiD is expressed at a negligible level under physiological condition and during infection (Fig. 4, A and B).