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Increasing the Vaccine Potential of Live M. bovis BCG by Coadministration with Plasmid DNA Encoding a Tuberculosis Prototype Antigen.

Bruffaerts N, Romano M, Denis O, Jurion F, Huygen K - Vaccines (Basel) (2014)

Bottom Line: Strongly increased T- and B-cell responses were observed with this protocol in C57BL/6 mice when compared to the administration of only BCG or in combination with an empty pDNA vector, as measured by Th1-type spleen cell cytokine secretion, specific IgG antibodies, as well as specific IFN-γ producing/cytolytic-CD8⁺ T-cells.Moreover, we observed a bystander activation induced by the coding plasmid, resulting in increased immune responses against other non-plasmid encoded, but BCG-expressed, antigens.In all, these results provide a proof of concept for a new TB vaccine, based on a BCG-plasmid DNA combination.

View Article: PubMed Central - PubMed

Affiliation: Scientific Institute of Public Health, Communicable and Infectious Diseases, Immunology, Brussels 1180, Belgium. nicolas.bruffaerts@wiv-isp.be.

ABSTRACT
The attenuated live M. bovis Bacille-Calmette-Guérin (BCG) is still the sole vaccine used against tuberculosis, but confers only variable efficacy against adult pulmonary tuberculosis (TB). Though no clear explanation for this limited efficacy has been given, different hypotheses have been advanced, such as the waning of memory T-cell responses, a reduced antigenic repertoire and the inability to induce effective CD8⁺ T-cell responses, which are known to be essential for latent tuberculosis control. In this study, a new BCG-based vaccination protocol was studied, in which BCG was formulated in combination with a plasmid DNA vaccine. As BCG is routinely administered to neonates, we have evaluated a more realistic approach of a simultaneous intradermal coadministration of BCG with pDNA encoding the prototype antigen, PPE44. Strongly increased T- and B-cell responses were observed with this protocol in C57BL/6 mice when compared to the administration of only BCG or in combination with an empty pDNA vector, as measured by Th1-type spleen cell cytokine secretion, specific IgG antibodies, as well as specific IFN-γ producing/cytolytic-CD8⁺ T-cells. Moreover, we observed a bystander activation induced by the coding plasmid, resulting in increased immune responses against other non-plasmid encoded, but BCG-expressed, antigens. In all, these results provide a proof of concept for a new TB vaccine, based on a BCG-plasmid DNA combination.

No MeSH data available.


Related in: MedlinePlus

Mycobacteria-specific IFN-γ responses against non plasmid-encoded, but BCG-expressed, antigens after BCG/pDNA co-vaccination. IFN-γ (pg/mL) was measured by ELISA in 72 h culture supernatant of spleen cells cultured with mycobacterial recombinant proteins PstS-3 and Ag85A, BCG culture filtrate (BCG CF) and with recombinant PPE44 (A) or purified ovalbumin (B). Data are presented as the mean ± standard error of the mean and representative of two independent experiments, including six mice per group. *p < 0.05 in comparison with BCG (ID) and BCG/control pDNA (ID) groups.
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vaccines-02-00181-f004: Mycobacteria-specific IFN-γ responses against non plasmid-encoded, but BCG-expressed, antigens after BCG/pDNA co-vaccination. IFN-γ (pg/mL) was measured by ELISA in 72 h culture supernatant of spleen cells cultured with mycobacterial recombinant proteins PstS-3 and Ag85A, BCG culture filtrate (BCG CF) and with recombinant PPE44 (A) or purified ovalbumin (B). Data are presented as the mean ± standard error of the mean and representative of two independent experiments, including six mice per group. *p < 0.05 in comparison with BCG (ID) and BCG/control pDNA (ID) groups.

Mentions: In order to find out whether the BCG/pDNA-PPE44 combination could affect the responses specific to antigens expressed by BCG other than PPE44, spleen cells were stimulated with two other BCG antigens, recombinant PstS-3 (Rv0928) and recombinant Ag85A (Rv3804c), or BCG culture filtrate. PstS-3 is one of the three putative phosphate transport receptors of Mtb, known to be an immunodominant B- and T-cell antigen of M. bovis BCG in H-2b haplotype mice [32]. PstS-3 is a potential tuberculosis vaccine candidate, and we have previously shown that mice vaccinated with PstS-3 DNA demonstrated significant and sustained reduction in bacterial CFU numbers in spleen and lungs for three months after Mtb challenge [33]. As shown in Figure 4A, the combination of BCG with pDNA-PPE44 increased the IFN-γ response to recombinant PstS-3 antigen about two-fold. IFN-γ responses to another immunodominant BCG antigen with a very promising vaccine potential, the mycolyl-transferase Ag85A, were even more strongly increased by the BCG/pDNA-PPE44 combination, and responses against BCG culture filtrate (in which Ag85A is one of the most abundant proteins) were equally augmented. Mice co-vaccinated with BCG and control DNA showed the same response as mice vaccinated with BCG alone.


Increasing the Vaccine Potential of Live M. bovis BCG by Coadministration with Plasmid DNA Encoding a Tuberculosis Prototype Antigen.

Bruffaerts N, Romano M, Denis O, Jurion F, Huygen K - Vaccines (Basel) (2014)

Mycobacteria-specific IFN-γ responses against non plasmid-encoded, but BCG-expressed, antigens after BCG/pDNA co-vaccination. IFN-γ (pg/mL) was measured by ELISA in 72 h culture supernatant of spleen cells cultured with mycobacterial recombinant proteins PstS-3 and Ag85A, BCG culture filtrate (BCG CF) and with recombinant PPE44 (A) or purified ovalbumin (B). Data are presented as the mean ± standard error of the mean and representative of two independent experiments, including six mice per group. *p < 0.05 in comparison with BCG (ID) and BCG/control pDNA (ID) groups.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494193&req=5

vaccines-02-00181-f004: Mycobacteria-specific IFN-γ responses against non plasmid-encoded, but BCG-expressed, antigens after BCG/pDNA co-vaccination. IFN-γ (pg/mL) was measured by ELISA in 72 h culture supernatant of spleen cells cultured with mycobacterial recombinant proteins PstS-3 and Ag85A, BCG culture filtrate (BCG CF) and with recombinant PPE44 (A) or purified ovalbumin (B). Data are presented as the mean ± standard error of the mean and representative of two independent experiments, including six mice per group. *p < 0.05 in comparison with BCG (ID) and BCG/control pDNA (ID) groups.
Mentions: In order to find out whether the BCG/pDNA-PPE44 combination could affect the responses specific to antigens expressed by BCG other than PPE44, spleen cells were stimulated with two other BCG antigens, recombinant PstS-3 (Rv0928) and recombinant Ag85A (Rv3804c), or BCG culture filtrate. PstS-3 is one of the three putative phosphate transport receptors of Mtb, known to be an immunodominant B- and T-cell antigen of M. bovis BCG in H-2b haplotype mice [32]. PstS-3 is a potential tuberculosis vaccine candidate, and we have previously shown that mice vaccinated with PstS-3 DNA demonstrated significant and sustained reduction in bacterial CFU numbers in spleen and lungs for three months after Mtb challenge [33]. As shown in Figure 4A, the combination of BCG with pDNA-PPE44 increased the IFN-γ response to recombinant PstS-3 antigen about two-fold. IFN-γ responses to another immunodominant BCG antigen with a very promising vaccine potential, the mycolyl-transferase Ag85A, were even more strongly increased by the BCG/pDNA-PPE44 combination, and responses against BCG culture filtrate (in which Ag85A is one of the most abundant proteins) were equally augmented. Mice co-vaccinated with BCG and control DNA showed the same response as mice vaccinated with BCG alone.

Bottom Line: Strongly increased T- and B-cell responses were observed with this protocol in C57BL/6 mice when compared to the administration of only BCG or in combination with an empty pDNA vector, as measured by Th1-type spleen cell cytokine secretion, specific IgG antibodies, as well as specific IFN-γ producing/cytolytic-CD8⁺ T-cells.Moreover, we observed a bystander activation induced by the coding plasmid, resulting in increased immune responses against other non-plasmid encoded, but BCG-expressed, antigens.In all, these results provide a proof of concept for a new TB vaccine, based on a BCG-plasmid DNA combination.

View Article: PubMed Central - PubMed

Affiliation: Scientific Institute of Public Health, Communicable and Infectious Diseases, Immunology, Brussels 1180, Belgium. nicolas.bruffaerts@wiv-isp.be.

ABSTRACT
The attenuated live M. bovis Bacille-Calmette-Guérin (BCG) is still the sole vaccine used against tuberculosis, but confers only variable efficacy against adult pulmonary tuberculosis (TB). Though no clear explanation for this limited efficacy has been given, different hypotheses have been advanced, such as the waning of memory T-cell responses, a reduced antigenic repertoire and the inability to induce effective CD8⁺ T-cell responses, which are known to be essential for latent tuberculosis control. In this study, a new BCG-based vaccination protocol was studied, in which BCG was formulated in combination with a plasmid DNA vaccine. As BCG is routinely administered to neonates, we have evaluated a more realistic approach of a simultaneous intradermal coadministration of BCG with pDNA encoding the prototype antigen, PPE44. Strongly increased T- and B-cell responses were observed with this protocol in C57BL/6 mice when compared to the administration of only BCG or in combination with an empty pDNA vector, as measured by Th1-type spleen cell cytokine secretion, specific IgG antibodies, as well as specific IFN-γ producing/cytolytic-CD8⁺ T-cells. Moreover, we observed a bystander activation induced by the coding plasmid, resulting in increased immune responses against other non-plasmid encoded, but BCG-expressed, antigens. In all, these results provide a proof of concept for a new TB vaccine, based on a BCG-plasmid DNA combination.

No MeSH data available.


Related in: MedlinePlus