IFNG and tuberculosis: To study whether MPT83 is recognised during human M. tuberculosis infection, PBMCs from 28 patients with active TB (13 males, 15 females, ages 22–74) and 20 TST-negative subjects (10 males, 10 females, ages 22–53) were stimulated with rMPT83, and both T cell proliferative and IFN-γ responses were measured.