The currently available vaccine against TB is a live attenuated form of Mycobacterium bovis, strain bacillus Calmette-Guérin (BCG), which has variable efficacy throughout the world.2 The immune response against TB relies on CD4+ T cells, and to some extent to CD8+ T cells,3 therefore protective vaccines require the induction of antigen-specific T cells through peptides presented by MHC-II and MHC-I, respectively, in infected macrophages. This evidence concerns the gene CD4 and tuberculosis.