MVA85A was safe and induced robust, polyfunctional, durable CD4 and CD8 T-cell responses in infants. These data support efficacy evaluation of MVA85A to prevent tuberculosis in infancy. Clinical Trials Registration. NCT00679159.

Vaccination with Mycobacterium bovis bacille Calmette-Guerin (BCG) has variable efficacy in preventing tuberculosis. Both BCG strain and route of administration have been implicated in determining efficacy; however, these variables are not considered in current clinical recommendations for vaccine choice. We evaluated antigen-specific immunity after percutaneous or intradermal administration of Japanese BCG or intradermal administration of Danish BCG. Ten weeks after vaccination of neonates, percutaneous Japanese BCG had induced significantly higher frequencies of BCG-specific interferon- gamma -producing CD4(+) and CD8(+) T cells in BCG-stimulated whole blood than did intradermal Danish BCG. Similarly, percutaneous vaccination with Japanese BCG resulted in significantly greater secretion of the T helper 1-type cytokines interferon- gamma, tumor necrosis factor- alpha , and interleukin-2; significantly lower secretion of the T helper 2-type cytokine interleukin-4; and greater CD4(+) and CD8(+) T cell proliferation. Thus, BCG strain and route of neonatal vaccination confer different levels of immune activation, which may affect the efficacy of the vaccine.

Rationale: Tuberculosis (TB) is a major cause of morbidity and mortality worldwide, thus there is an urgent need for novel TB vaccines. Objectives: We investigated a novel TB vaccine candidate, M72/ AS01, in a phase IIa trial of bacille Calmette-Gué rin-vaccinated, HIV-uninfected, and Mycobacterium tuberculosis (Mtb)-infected and -uninfected adults in South Africa. Methods: Two doses of M72/AS01 were administered to healthy adults, with and without latent Mtb infection. Participants were monitored for 7 months after the first dose; cytokine production profiles, cell cycling, and regulatory phenotypes of vaccine-induced T cells were measured by flow cytometry. Measurements and Main Results: The vaccine had a clinically acceptable safety profile, and induced robust, long-lived M72-specific T-cell and antibody responses. M72-specific CD4 T cells produced multiple combinations of Th1 cytokines. Analysis of T-cell Ki67 expression showed that most vaccination-induced T cells did not express Th1 cytokines or IL-17; these cytokine-negative Ki67 1 T cells included subsets of CD4 T cells with regulatory phenotypes. PD-1, a negative regulator of activated T cells, was transiently expressed on M72-specific CD4 T cells after vaccination. Specific T-cell subsets were present at significantly higher frequencies after vaccination of Mtb-infected versus -uninfected participants. Conclusions: M72/AS01 is clinically well tolerated in Mtb-infected and -uninfected adults, induces high frequencies of multifunctional T cells, and boosts distinct T-cell responses primed by natural Mtb infection. Moreover, these results provide important novel insights into how this immunity may be appropriately regulated after novel TB vaccination of Mtb-infected and -uninfected individuals. Clinical trial registered with www.clinicaltrials.gov (NCT 00600782).Keywords: tuberculosis; vaccine; T cell; cytokine; proliferation Tuberculosis (TB) remains a major cause of morbidity and mortality, with approximately 9 million new cases and 1.5 million deaths worldwide each year (1). Bacille Calmette-Guérin (BCG) provides protection against miliary TB and TB meningitis in children (2); however, BCG provides variable efficacy against pulmonary TB in adults (3), the most common clinical manifestation of the disease. Mycobacterium tuberculosis (Mtb) is transmitted primarily by adults; therefore novel, effective TB vaccines are urgently needed to target this population, and thereby reduce the burden of TB disease worldwide.Phase I and II clinical trials of several novel candidate TB vaccines have either been completed or are currently ongoing (4). These vaccines include the candidate recombinant fusion protein vaccine M72, formulated with GlaxoSmithKline Vaccines Approximately one-third of the world's population is infected with Mycobacterium tuberculosis (Mtb), and despite the widespread use of the bacille Calmette-Guérin vaccine, tuberculosis (TB) remains a major cause of morbidity and mortality. There is an urgent need to develop novel TB vaccines that are safe,...