The mycolyltransferase Ag85B is the major antigen produced and secreted from all mycobacterial species during infection (Belisle et al., 1997) and has been shown to play an important role in the induction of protective immunity (Andersen, 1994; Baldwin et al., 1998) by inducing strong T cell proliferation and IFN-γ secretion (Launois et al., 1994; Takamura et al., 2005). The gene discussed is IFNG; the disease is infection.