Figure 1.

Pathogenesis of M.tb: Upon aerosol inhalation, alveolar macrophages degrade bacteria through ROS production and phagolysosomal degradation, which activates other immune cells such as T cells and B cells, further providing defense against the pathogen. However, M.tb. adapts the ability to inhibit phagolysosomal degradation, and therefore under unfavorable conditions such as hypoxia undergo dormancy. As the environmental conditions become favorable, the bacteria resuscitate, resulting in active disease. (Red represents M.tb. antigens).