Protection against tuberculosis with homologous or heterologous protein/vector vaccine approaches is not dependent on CD8+ T cells

J Immunol. 2013 Sep 1;191(5):2514-2525. doi: 10.4049/jimmunol.1301161. Epub 2013 Jul 31.

Abstract

Considerable effort has been directed to develop Mycobacterium tuberculosis vaccines to boost bacille Calmette-Guérin or for those who cannot be immunized with bacille Calmette-Guérin. We hypothesized that CD4(+) and CD8(+) T cell responses with a heterologous prime/boost vaccine approach could induce long-lived vaccine efficacy against M. tuberculosis in C57BL/6 mice. We produced an adenovirus vector expressing ID93 (Ad5-ID93) for induction of CD8 T cells to use with our candidate tuberculosis vaccine, ID93/glucopyranosyl lipid adjuvant (GLA)-stable emulsion (SE), which induces potent Th1 CD4 T cells. Ad5-ID93 generates ID93-specific CD8(+) T cell responses and induces protection against M. tuberculosis. When Ad5-ID93 is administered in a prime-boost strategy with ID93/GLA-SE, both CD4(+) and CD8(+) T cells are generated and provide protection against M. tuberculosis. In a MHC class I-deficient mouse model, all groups including the Ad5-ID93 group elicited an Ag-specific CD4(+) T cell response and significantly fewer Ag-specific CD8(+) T cells, but were still protected against M. tuberculosis, suggesting that CD4(+) Th1 T cells could compensate for the loss of CD8(+) T cells. Lastly, the order of the heterologous immunizations was critical. Long-lived vaccine protection was observed only when Ad5-ID93 was given as the boost following an ID93/GLA-SE prime. The homologous ID93/GLA-SE prime/boost regimen also induced long-lived protection. One of the correlates of protection between these two approaches was an increase in the total number of ID93-specific IFN-γ-producing CD4(+) T cells 6 mo following the last immunization. Our findings provide insight into the development of vaccines not only for tuberculosis, but other diseases requiring T cell immunity.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenoviridae / genetics
  • Adjuvants, Immunologic / administration & dosage*
  • Animals
  • Antigens, Bacterial / immunology
  • Blotting, Western
  • CD8-Positive T-Lymphocytes / immunology*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Flow Cytometry
  • Genetic Vectors
  • Immunization, Secondary / methods*
  • Mice
  • Mice, Inbred C57BL
  • Mycobacterium tuberculosis
  • Recombinant Fusion Proteins / immunology
  • Tuberculosis / immunology
  • Tuberculosis / prevention & control*
  • Tuberculosis Vaccines / immunology*

Substances

  • Adjuvants, Immunologic
  • Antigens, Bacterial
  • Recombinant Fusion Proteins
  • Tuberculosis Vaccines