This proposal seeks to understand in greater detail the mechanisms by which Mycobacterium tuberculosis blocks the priming of effective host immunity, with the ultimate goal of using this information to create more effective live vaccine strains. Previous work identified multiple mycobacterial genes involved in blocking apoptosis of infected host cells, which is intimately linked to the ability of the pathogen to prevent presentation of its antigens by MHC class I. Extensive preliminary work has also identified genes in M. tuberculosis that interfere with MHC class II antigen presentation, and genes that block production of key cytokines. A major goal of this proposal is to construct safely attenuated strains of M. tuberculosis in which specific immune evasion genes have been deleted, thus creating more effective vaccines for priming of anti- mycobacterial immunity. The approach involves identifying the most potent anti- apoptotic genes from a group of four candidates that have already been partially characterized, and combining mutations in these with strongly attenuating auxotrophy mutations to eliminate virulence. Precise mutations in the genes of interest will be created using allelic exchange mediated by specialized transducing phages, a methodology that is well established in the laboratory of the PI and his collaborators. The potency of candidate vaccine strains will be further enhanced by incorporating additional mutations in genes that interfere with MHC class II presentation, or with production of IL-12p70 or TNF. Immunological studies of CD4 and CD8 T cell priming by candidate vaccine strains will be carried out in mouse models, allowing identification of the most favorable combinations of specific gene deletions to advance into preclinical vaccination studies in rodents. Studies of the induction of stable T cell memory by candidate vaccine strains will be performed in mice, and the impact of boosting primary responses with mycobacterial proteins will also be initiated. Overall, the proposed studies will significantly advance our understanding of the host-pathogen interaction in tuberculosis, and contribute directly to vaccine development for prevention and control of this major human disease.
This proposal aims to understand in greater detail the mechanisms by which Mycobacterium tuberculosis evades host immunity to cause serious disease and mortality. The information gained will be applied to the design and construction of better vaccines for the prevention of tuberculosis.
|Prados-Rosales, Rafael; Carreño, Leandro J; Batista-Gonzalez, Ana et al. (2014) Mycobacterial membrane vesicles administered systemically in mice induce a protective immune response to surface compartments of Mycobacterium tuberculosis. MBio 5:e01921-14|
|Venkataswamy, Manjunatha M; Ng, Tony W; Kharkwal, Shalu S et al. (2014) Improving Mycobacterium bovis bacillus Calmette-Guèrin as a vaccine delivery vector for viral antigens by incorporation of glycolipid activators of NKT cells. PLoS One 9:e108383|
|Panas, Michael W; Sixsmith, Jaimie D; White, KeriAnn et al. (2014) Gene deletions in Mycobacterium bovis BCG stimulate increased CD8+ T cell responses. Infect Immun 82:5317-26|
|Sixsmith, Jaimie D; Panas, Michael W; Lee, Sunhee et al. (2014) Recombinant Mycobacterium bovis bacillus Calmette-Guérin vectors prime for strong cellular responses to simian immunodeficiency virus gag in rhesus macaques. Clin Vaccine Immunol 21:1385-95|
|Carreño, Leandro J; Kharkwal, Shalu Sharma; Porcelli, Steven A (2014) Optimizing NKT cell ligands as vaccine adjuvants. Immunotherapy 6:309-20|
|Kozakiewicz, Lee; Chen, Yong; Xu, Jiayong et al. (2013) B cells regulate neutrophilia during Mycobacterium tuberculosis infection and BCG vaccination by modulating the interleukin-17 response. PLoS Pathog 9:e1003472|
|Venkataswamy, Manjunatha M; Goldberg, Michael F; Baena, Andres et al. (2012) In vitro culture medium influences the vaccine efficacy of Mycobacterium bovis BCG. Vaccine 30:1038-49|
|Sweeney, Kari A; Dao, Dee N; Goldberg, Michael F et al. (2011) A recombinant Mycobacterium smegmatis induces potent bactericidal immunity against Mycobacterium tuberculosis. Nat Med 17:1261-8|