Bcells and their regulatory functions during Tuberculosis: Latency and active disease.

Tuberculosis (TB) is a global epidemic with devastating consequences. Emerging evidence suggests that B-cells have the ability to modulate the immune response and understanding these roles during Mycobacterium tuberculosis (M.tb) infection can help to find new strategies to treat TB. The immune system of individuals with pulmonary TB form granulomas in the lung which controls the infection by inhibiting the M.tb growth and acts as a physical barrier. Thereafter, surviving M.tb become dormant and in most cases the host's immunity prevents TB reactivation. B-cells execute several immunological functions and are regarded as protective regulators of immune responses by antibody and cytokine production, as well as presenting antigen. Some of these B-cells, or regulatory B-cells, have been shown to express death-inducing ligands, such as Fas ligand (FasL). This expression and binding to the Fas receptor leads to apoptosis, a major immune regulation mechanism, in addition to the ability to induce T-cell tolerance. Here, I discuss the relevance of B-cells, in particular their non-humoral functions by addressing their regulatory properties during M.tb infection.