Recombinant Mycobacterium bovis BCG expressing pertussis toxin subunit S1 induces protection against an intracerebral challenge with live Bordetella pertussis in mice.
The recent development of acellular pertussis vaccines has been a significant improvement in the conventional whole-cell diphtheria-pertussis-tetanus toxoid vaccines, but high production costs will limit its widespread use in developing countries. Since Mycobacterium bovis BCG vaccination against tuberculosis is used in most developing countries, a recombinant BCG-pertussis vaccine could be a more viable alternative. We have constructed recombinant BCG (rBCG) strains expressing the genetically detoxified S1 subunit of pertussis toxin 9K/129G (S1PT) in fusion with either the beta-lactamase signal sequence or the whole beta-lactamase protein, under control of the upregulated M. fortuitum beta-lactamase promoter, pBlaF*. Expression levels were higher in the fusion with the whole beta-lactamase protein, and both were localized to the mycobacterial cell wall. The expression vectors were relatively stable in vivo, since at two months 85% of the BCG recovered from the spleens of vaccinated mice maintained kanamycin resistance. Spleen cells from rBCG-S1PT-vaccinated mice showed elevated gamma interferon (IFN-gamma) and low interleukin-4 (IL-4) production, as well as increased proliferation, upon pertussis toxin (PT) stimulation, characterizing a strong antigen-specific Th1-dominant cellular response. The rBCG-S1PT strains induced a low humoral response against PT after 2 months. Mice immunized with rBCG-S1PT strains displayed high-level protection against an intracerebral challenge with live Bordetella pertussis, which correlated with the induction of a PT-specific cellular immune response, reinforcing the importance of cell-mediated immunity in the protection against B. pertussis infection. Our results suggest that rBCG-expressing pertussis antigens could constitute an effective, low-cost combined vaccine against tuberculosis and pertussis.
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Centro de Biotecnologia, Instituto Butantan, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
Dias
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Mazzantini
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Miyaji
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Gamberini
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Quintilio
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Gebara
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Cardoso
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Winter
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Gicquel
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Rappuoli
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Leite
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D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D001921:Brain / Q000382:microbiology; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009163:Mycobacterium bovis / Q000235:genetics* / Q000276:immunology; D037342:Pertussis Toxin; D010567:Pertussis Vaccine / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology*; D010566:Virulence Factors, Bordetella / Q000276:immunology*; D014917:Whooping Cough / Q000517:prevention & control
D000907:Antibodies, Bacterial; D010567:Pertussis Vaccine; D014614:Vaccines, Synthetic; D010566:Virulence Factors, Bordetella; D015847:Interleukin-4; D007371:Interferon-gamma; D037342:Pertussis Toxin