MTBVAC-Based TB-HIV Vaccine Is Safe, Elicits HIV-T Cell Responses, and Protects against in Mice.

The tuberculosis (TB) vaccine MTBVAC is the only live-attenuated ()-based vaccine in clinical development, and it confers superior protection in different animal models compared to the current vaccine, BCG ( bacillus Calmette-Guérin). With the aim of using MTBVAC as a vector for a dual TB-HIV vaccine, we constructed the recombinant MTBVAC.HIVA strain. First, we generated a lysine auxotroph of MTBVAC (MTBVACΔ) by deleting the gene. Then the auxotrophic MTBVACΔ was transformed with the -mycobacterial vector p2auxo.HIVA, harboring the -complementing gene and the HIV-1 clade A immunogen HIVA. This TB-HIV vaccine conferred similar efficacy to the parental strain MTBVAC against challenge in mice. MTBVAC.HIVA was safer than BCG and MTBVAC in severe combined immunodeficiency (SCID) mice, and it was shown to be maintained up to 42 bacterial generations and up to 100 days after inoculation . The MTBVAC.HIVA vaccine, boosted with modified vaccinia virus Ankara (MVA).HIVA, induced HIV-1 and -specific interferon-γ-producing T cell responses and polyfunctional HIV-1-specific CD8+ T cells producing interferon-γ (IFN-γ), tumor necrosis factor alpha (TNF-α), and CD107a in BALB/c mice. Here we describe new tools to develop combined vaccines against TB and HIV with the potential of expansion for other infectious diseases.