Infection with the tubercle bacilli induces cell mediated immunity which manifests as delayed hypersensitivity and resistance to infection (immunity ). The only specific immune mechanism effective against tubercle bacilli is cell mediated type. The helper T cell gets activated, releasing cytokines such as interferon gamma, interleukin 1 and 2, toxic necrosis factor alpha that exes different biological effects. Reference : Anathanarayan & paniker's 9th edition, pg no:350