IFNG and infection: Concerning the immune correlates of infection assessed in the present study, the positive correlation of the specific IFN-γ levels to E/C and Rv3615c, as well as the specific antibody levels to the surface protein MPB83, with the severity of the pathology, are in agreement with other studies performed in calf and goats experimentally challenged with M. bovis and M. caprae respectively [24], [27], [39], [40].