Identification of CD8 T Cell Epitopes Against Mycobacterium tuberculosis

Although the effective immune response against Mycobacterium tuberculosis (M. tuberculosis, Mtb) is primarily due to cell-mediated immunity, the mechanisms by which T cells participate in the control of infection are still not completely understood. The importance of CD8+ T cells in the immune response to tuberculosis has been recognized by many researchers [1]. Experimental evidence from the murine model indicated that CD8+ T cells could be important to the control of Mycobacterium tuberculosis infection in vivo [2-5]. The isolation of M. tuberculosis-specific CD8+ T cells from infected mice and human clearly showed that this subset could be induced during infection [6-8]. Reports on epitope-specific M. tuberculosis reactive CD8+ T cells, which are present at very high frequencies in the peripheral blood of PPD positive individuals and patients with active tuberculosis, support the importance of CD8+ T cells to the immunity of M. tuberculosis and emphasize that the CD8+ T cell subset should be considered to the design of new anti-tuberculosis vaccines [9, 10]. CD8+ T cells may contribute to the control of M. tuberculosis infection through four mechanisms: (1) Cytokine release, such as IFN-γ and TNF-α; (2) Cytotoxicity via granuledependent exocytosis pathway; (3) Cytotoxicity mediated through Fas/Fas ligand interaction; (4) Direct microbicidal activity.