Tuberculosis remains a major health problem throughout the world causing large number of deaths. Effective disease control and eradication programs require the identification of major antigens recognized by the protective responses againstM. tuberculosis. In this study, we have investigated humoral and cellular immune responses toM. tuberculosis-specific Ag85A, Ag85B, and ESAT-6 antigens in Brazilian patients with pulmonary (P,n=13) or extrapulmonary (EP,n=12) tuberculosis, patients undergoing chemotherapy (PT,n=23), and noninfected healthy individuals (NI,n=7). Compared to NI, we observed increased levels of IgG1 responses to Ag85B and ESAT-6 in P and PT groups. Regarding cellular immunity, Ag85A and ESAT-6 were able to discriminate P, PT, and EP patients from healthy individuals by IFN-γ production and P and PT groups from EP individuals by production of TNF-α. In summary, these findings demonstrate the ability of Ag85A, Ag85B, and ESAT-6 to differentiate TB patients from controls by IgG1, IFN-γ and TNF-α production.
