Vaccination with a Sindbis virus-based DNA vaccine expressing antigen 85B induces protective immunity against Mycobacterium tuberculosis

Infect Immun. 2005 Nov;73(11):7727-35. doi: 10.1128/IAI.73.11.7727-7735.2005.

Abstract

To improve DNA vaccination against Mycobacterium tuberculosis, we evaluated the effectiveness of a Sindbis virus-based DNA construct expressing the tuberculosis antigen 85B (Sin85B). The protective efficacy of Sin85B was initially assessed by aerogenically challenging immunized C57BL/6 mice with virulent Mycobacterium tuberculosis. At 1 and 7 months postinfection, the lung bacterial burdens were considerably reduced and the lung pathology was improved in vaccinated mice compared to naive controls. Furthermore, the mean survival period for Sin85B-immunized mice (305 +/- 9 days) after the tuberculous challenge was extended 102 days relative to the naive mice (203 +/- 13 days) and was essentially equivalent to the survival time of Mycobacterium bovis BCG-vaccinated mice (294 +/- 15 days). The essential role of gamma interferon (IFN-gamma) in Sin85B-mediated protection was established by showing that significantly increased levels of IFN-gamma mRNA were present postinfection in lung cells from vaccinated mice relative to control mice and by demonstrating that IFN-gamma depletion prior to challenge abolished the vaccine-induced protection. The substantial antituberculosis protective responses induced by Sin85B immunization of CD4-/- mice strongly suggested that CD8 cells partially mediate Sin85B-induced protective immunity. Interestingly, Sin85B vaccination did not protect RNase L-/- (a key enzyme in the innate antiviral response) mice while significant protection was detected in RNase L-/- mice immunized with either BCG or a conventional DNA plasmid expressing antigen 85B. These data show that immunization with Sin85B offers protection similar to BCG in a murine model of pulmonary tuberculosis and suggest that Sin85B-induced protection is dependent upon both innate and acquired immune mechanisms.

MeSH terms

  • Aerosols
  • Animals
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / immunology*
  • CD4 Antigens / genetics
  • CD8 Antigens / genetics
  • CD8-Positive T-Lymphocytes / immunology
  • Endoribonucleases / deficiency
  • Endoribonucleases / genetics
  • Genetic Vectors / genetics
  • Interferon-gamma / immunology
  • Lung / microbiology
  • Mice
  • Mice, Knockout
  • Mycobacterium tuberculosis / immunology*
  • Sindbis Virus / genetics*
  • Tuberculosis / immunology
  • Tuberculosis / microbiology
  • Tuberculosis / prevention & control*
  • Tuberculosis Vaccines / genetics
  • Tuberculosis Vaccines / immunology*
  • Vaccination
  • Vaccines, DNA / genetics*
  • Vaccines, DNA / immunology*

Substances

  • Aerosols
  • Antigens, Bacterial
  • CD4 Antigens
  • CD8 Antigens
  • Tuberculosis Vaccines
  • Vaccines, DNA
  • antigen 85B, Mycobacterium leprae
  • Interferon-gamma
  • Endoribonucleases
  • 2-5A-dependent ribonuclease