Enhanced immunogenicity of CD4(+) t-cell responses and protective efficacy of a DNA-modified vaccinia virus Ankara prime-boost vaccination regimen for murine tuberculosis.
DNA vaccines whose DNA encodes a variety of antigens from Mycobacterium tuberculosis have been evaluated for immunogenicity and protective efficacy. CD8(+) T-cell responses and protection achieved in other infectious disease models have been optimized by using a DNA immunization to prime the immune system and a recombinant virus encoding the same antigen(s) to boost the response. A DNA vaccine (D) and recombinant modified vaccinia virus Ankara (M) in which the DNA encodes early secreted antigenic target 6 and mycobacterial protein tuberculosis 63 synthesized, and each was found to generate specific gamma interferon (IFN-gamma)-secreting CD4(+) T cells. Enhanced CD4(+) IFN-gamma T-cell responses were produced by both D-M and M-D immunization regimens. Significantly higher levels of IFN-gamma were seen with a D-D-D-M immunization regimen. The most immunogenic regimens were assessed in a challenge study and found to produce protection equivalent to that produced by Mycobacterium bovis BCG. Thus, heterologous prime-boost regimens boost CD4(+) as well as CD8(+) T-cell responses, and the use of heterologous constructs encoding the same antigen(s) may improve the immunogenicity and protective efficacy of DNA vaccines against tuberculosis and other diseases.
McShane
H
H
Nuffield Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom. helen.mcshane@ndm.ox.ac.uk
Brookes
R
R
Gilbert
S C
SC
Hill
A V
AV
D000595:Amino Acid Sequence; D000818:Animals; D001500:BCG Vaccine / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D015169:Colony Count, Microbial; D005260:Female; D007117:Immunization, Secondary; D007371:Interferon-gamma / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000276:immunology; D014376:Tuberculosis / Q000517:prevention & control*; D014611:Vaccination; D019444:Vaccines, DNA / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology*
D001500:BCG Vaccine; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic; D007371:Interferon-gamma