title: DNA-Launched Alphavirus Replicons Encoding a Fusion of Mycobacterial Antigens Acr and Ag85B Are Immunogenic and Protective in a Murine Model of TB Infection.
abstract: There is an urgent need for effective prophylactic measures against Mycobacterium tuberculosis (Mtb) infection, particularly given the highly variable efficacy of Bacille Calmette-Guerin (BCG), the only licensed vaccine against tuberculosis (TB). Most studies indicate that cell-mediated immune responses involving both CD4+ and CD8+ T cells are necessary for effective immunity against Mtb. Genetic vaccination induces humoral and cellular immune responses, including CD4+ and CD8+ T-cell responses, against a variety of bacterial, viral, parasitic and tumor antigens, and this strategy may therefore hold promise for the development of more effective TB vaccines. Novel formulations and delivery strategies to improve the immunogenicity of DNA-based vaccines have recently been evaluated, and have shown varying degrees of success. In the present study, we evaluated DNA-launched Venezuelan equine encephalitis replicons (Vrep) encoding a novel fusion of the mycobacterial antigens α-crystallin (Acr) and antigen 85B (Ag85B), termed Vrep-Acr/Ag85B, for their immunogenicity and protective efficacy in a murine model of pulmonary TB. Vrep-Acr/Ag85B generated antigen-specific CD4+ and CD8+ T cell responses that persisted for at least 10 wk post-immunization. Interestingly, parenterally administered Vrep-Acr/Ag85B also induced T cell responses in the lung tissues, the primary site of infection, and inhibited bacterial growth in both the lungs and spleens following aerosol challenge with Mtb. DNA-launched Vrep may, therefore, represent an effective approach to the development of gene-based vaccines against TB, particularly as components of heterologous prime-boost strategies or as BCG boosters.
authors: Department of Microbiology, Immunology and Parasitology, LSU Health Sciences Center, New Orleans, Louisiana, United States of America.
authors: Neha
authors: N
authors: Dalmia
authors: Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors: William B
authors: WB
authors: Klimstra
authors: Department of Microbiology, Immunology and Parasitology, LSU Health Sciences Center, New Orleans, Louisiana, United States of America.
authors: Carol
authors: C
authors: Mason
authors: Department of Microbiology, Immunology and Parasitology, LSU Health Sciences Center, New Orleans, Louisiana, United States of America; Department of Microbiology, Immunology and Parasitology, LSU Health Sciences Center, New Orleans, Louisiana, United States of America.
authors: Alistair J
authors: AJ
authors: Ramsay
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000276:immunology*; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000473:pathology; D004195:Disease Models, Animal; D004666:Encephalitis Virus, Venezuelan Equine / Q000235:genetics / Q000276:immunology*; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D051379:Mice; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology*; D012093:Replicon / Q000276:immunology*; D032581:Tuberculosis Vaccines / Q000235:genetics / Q000276:immunology*; D014397:Tuberculosis, Pulmonary / Q000235:genetics / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D014611:Vaccination; D038201:alpha-Crystallins / Q000235:genetics / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D032581:Tuberculosis Vaccines; D038201:alpha-Crystallins; D000217:Acyltransferases; C121433:antigen 85B, Mycobacterium tuberculosis