Immune response to Mycobacterium tuberculosis

Infections with Mycobacterium tuberculosis (MTB) induce complex immune responses involving an orchestrated interplay of innate and adaptive immune mechanisms. Why the immune system fails to eradicate the pathogen and at best achieves control of infection in the latent stage, still remains an unsolved mystery even more than 100 years after the discovery of MTB by Robert Koch. This article provides an overview of the current state of the art in the constantly evolving field of tuberculosis (TB) immunology. This review focuses on a change of paradigm proposing that in the latent stage MTB is anything but dormant and that latent TB is not merely a state of bacterial stasis but a state of dynamic bacterial and immunological equilibrium. The understanding of these dynamics is crucial for the development of new drugs against MTB as well as vaccines that aim to provide effective protection against the disease.