Prevention of tuberculosis in macaques after intravenous BCG immunization

Abstract Mycobacterium tuberculosis (Mtb) is the leading cause of death from infection worldwide 1 . The only available vaccine, BCG (Bacillus Calmette–Guérin), is given intradermally and has variable efficacy against pulmonary tuberculosis, the major cause of mortality and disease transmission 1,2 . Here we show that intravenous administration of BCG profoundly alters the protective outcome of Mtb challenge in non-human primates ( Macaca mulatta ). Compared with intradermal or aerosol delivery, intravenous immunization induced substantially more antigen-responsive CD4 and CD8 T cell responses in blood, spleen, bronchoalveolar lavage and lung lymph nodes. Moreover, intravenous immunization induced a high…