IFNG and tuberculosis: Ag85A and Ag85B, initially purified from Mycobacterium bovis bacillus Calmette–Guérin (BCG)/Mycobacterium tuberculosis culture filtrate respectively, induce strong T-cell proliferation and IFN-γ production in most healthy individuals latently infected with M. tuberculosis and in BCG-vaccinated mice and humans but not in tuberculosis patients.