This vaccine candidate was as safe as its parental BCG in immunocompromised nu/nu mice and improved protection against a high-dose (2.5 × 105 CFU) infection with Mtb H37Rv, accompanied by increased levels of IFN-γ+ T lymphocytes in spleens compared with mice receiving BCG18, but this version had not evaluated the capacity to elicit multifunctional effector T cells yet in lungs. Here, IFNG is linked to infection.