Conceptual view of Ab-mediated protection induced by a TB vaccine. (A) The ideal vaccine would prevent M. tuberculosis infection in the uninfected and development of disease in the already infected individual through mucosal airway and/or systemic vaccination. (B) Induction of protective M. tuberculosis antigen-specific antibody responses with potential enhancement of cell-mediated responses. (C) Illustration of several antibody-mediated functions against M. tuberculosis, including opsonization, FcR-mediated phagocytosis and intracellular growth reduction, influence on the host’s inflammatory response, direct effects on the M. tuberculosis physiology, and influence of immune complexes on the host and host cells.