[Mycobacterium tuberculosis--intracellular pathogen. Relationship between mycobacteria and the host].

In mutual interactions between mycobacteria and the host the crucial for the elimination of the pathogen is the first phase of infection. It depends from one side on the innate immunity of the host and on the virulence of mycobacteria from the other. These not exactly well known factors of M. tuberculosis which contribute to this virulence leading to the development of the disease are discussed. Also bactericidal mechanisms of host immunity as well as how mycobacteria can alter this system to evoid killing are presented.