Human pulmonary tuberculosis (TB) is a worldwide public health problem, which is caused by Mycobacterium tuberculosis. It is a fact that one third of the world's population is infected with this mycobacteria, however, only a minority of people infected by M. tuberculosis may develop a clinical disease. In general, about 90% have their bacilli under control in a latent state throughout their lives by means of their immune responses. About 5% will develop primary progressive TB and the remaining 5% will develop the disease in the later stages of their lives, which is known as reactivation or post-primary TB. In resistant individuals, control of the infection mainly requires development of a Th1 cell immunity response. This type of response involves participation of alveolar macrophages and T CD4+, CD8+ and T gammadelta lymphocytes, and production of cytokines such as IL-2, IFN-gamma, IL-12, IL-18 and TNF-alpha, as well as chemokines such as RANTES, MCP-1, MIP-1alpha and IL-8 which play an important role in the migration of different cell subpopulations to the infection site for the formation of granulome. In addition, the role of "natural killer" (NK) cells, along with epitelial cells, is essential as part of the innate immune response.