Host Immune Response to Mycobacterium tuberculosis Infection: Implications for Vaccine Development.

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) infection, including pulmonary tuberculosis and extrapulmonary tuberculosis. About a quarter of the people in the world are infected with TB, but only 5-10% of them will progress to active TB, posing a major challenge to the eradication of TB. The study of the host immune response to Mtb infection is a key aspect of the development of effective vaccines and immunotherapies to eradicate tuberculosis. In this review, we delve into the overview of animal models of TB infection and the host's innate and adaptive immune responses to Mtb infection. We discuss how Mtb is recognized and phagocytosed by macrophages, how it evades immune responses, the recruitment and mobilization of neutrophils and monocytes, the role of natural killer cells during the infection process, how dendritic cells initiate adaptive immunity, the important roles of CD4⁺ T cells and their subtypes in TB infection, how CD8⁺ T cells exert cytotoxic functions, and how B cells produce antibodies and exhibit memory characteristics to eliminate pathogens. Furthermore, we review the tuberculosis vaccines currently entering clinical trials, emphasizing that studying the host's immune responses following Mtb infection is crucial for the development of more effective vaccines, providing a theoretical foundation and direction for the treatment of tuberculosis.