|Title||Increased B and T cell responses in M. bovis bacille Calmette-Guérin vaccinated pigs co-immunized with plasmid DNA encoding a prototype tuberculosis antigen|
|Author(s)||Bruffaerts, Nicolas; Pedersen, Lasse E.; Vandermeulen, Gaëlle; Préat, Véronique; Stockhofe, Norbert; Huygen, Kris; Romano, Marta|
|Source||PLoS One 10 (2015)7. - ISSN 1932-6203|
|Department(s)||CVI Infection Biology|
|Publication type||Refereed Article in a scientific journal|
The only tuberculosis vaccine currently available, bacille Calmette-Guérin (BCG) is a poor inducer of CD8+ T cells, which are particularly important for the control of latent tuberculosis and protection against reactivation. As the induction of strong CD8+ T cell responses is a hallmark of DNA vaccines, a combination of BCG with plasmid DNA encoding a prototype TB antigen (Ag85A) was tested. As an alternative animal model, pigs were primed with BCG mixed with empty vector or codon-optimized pAg85A by the intradermal route and boosted with plasmid delivered by intramuscular electroporation. Control pigs received unformulated BCG. The BCG-pAg85A combination stimulated robust and sustained Ag85A specific antibody, lymphoproliferative, IL-6, IL-10 and IFN-γ responses. IgG1/IgG2 antibody isotype ratio reflected the Th1 helper type biased response. T lymphocyte responses against purified protein derivative of tuberculin (PPD) were induced in all (BCG) vaccinated animals, but responses were much stronger in BCG-pAg85A vaccinated pigs. Finally, Ag85A-specific IFN-γ producing CD8+ T cells were detected by intracellular cytokine staining and a synthetic peptide, spanning Ag85A131-150 and encompassing two regions with strong predicted SLA-1∗0401/SLA-1∗0801 binding affinity, was promiscuously recognized by 6/6 animals vaccinated with the BCG-pAg85A combination. Our study provides a proof of concept in a large mammalian species, for a new Th1 and CD8+ targeting tuberculosis vaccine, based on BCG-plasmid DNA co-administration.