Mycobacterial lipolytic enzymes: a gold mine for tuberculosis research

Tuberculosis (TB) is one of the deadliest infectious diseases worldwide with a strong impact in developing countries. Mycobacterium tuberculosis, the etiological agent of TB, has a high capacity to evade the host immune system and establish a chronic, asymptomatic and latent infection. In a latent TB infection, persistent bacilli are present in a non-replicating dormant state within host granulomas. During reactivation, bacilli start replicating again leading to an active TB infection that can be highly contagious. Mycobacterial lipids and lipolytic enzymes are thought to play important physiological roles during dormancy and reactivation. The role of lipolytic enzymes in the physiology of M. tuberculosis and physiopathology of the disease will be discussed in this review, with an emphasis on the secreted or cell wall-associated, surface exposed lipolytic enzymes characterized to date. Studies on the localization, enzymatic activity and immunological properties of these enzymes highlighted their possible usefulness as new diagnostic markers in the fight against TB.