Journal of Clinical and Cellular Immunology
Open Access

Abstract

The Role of T cells In Mucosal Immunity against Mycobacterium tuberculosis (Mtb) Infection: A Review of Current Understanding

Fekadu Abebe

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) remains one of the most important infectious diseases globally. Because Bacille Calmette-Guerin (BCG) vaccine is short of preventing transmission, the search for an efficacious vaccine to either augment that of BCG or to replace has been intensified globally. Currently, there are many candidate vaccines in different stages of clinical trials but none of these has achieved the desired efficacy to control TB. One central issue in TB immunology is lack of clear understanding as to what leads to immune protection or development of clinical disease. Tuberculosis is primarily a disease of the lungs and the main portal of entry of Mtb to the lungs and systemic organs is the respiratory tract and its mucosal surfaces. Therefore, the role of mucosal immunity against Mtb infection has been the subject of several investigations quite for some time. There is emerging evidence that mucosal immunity against TB may be critical for the control of Mtb infection and development of an efficacious vaccine. Although it is generally believed that type helper T (Th1) cells are critical for protection against Mtb infection, emerging data show that non-conventional T cells could play a vital role in protection against TB, particularly in the respiratory mucosa. In this review, current understanding on the role of various T cell subsets, with focus on lymphocytes collectively called “innate-like lymphocytes”, including gammadelta (γδ) T cells, natural killer T (NKT) cells, and mucosal-associated invariant T (MAIT) cells will be presented.