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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

Specific Th1-type cytokine production induced by BCG/pDNA co-vaccination. IFN-γ, IL-2, TNF-α and IL-17A levels (pg/mL) were measured by ELISA in 24 h (IL-2) or 72 h (IFN-γ, TNF-α and IL-17A) culture supernatants of splenocytes from vaccinated C57BL/6 mice, after restimulation with the PPE44 MHC Class II-restricted synthetic peptide spanning amino acids 1–20 (PPE44[1–20]) or the recombinant PPE44 protein (rPPE44). RPMI, non-stimulated cells. ID, intradermally. IM, intramuscularly. 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; **p < 0.005.
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vaccines-02-00181-f002: Specific Th1-type cytokine production induced by BCG/pDNA co-vaccination. IFN-γ, IL-2, TNF-α and IL-17A levels (pg/mL) were measured by ELISA in 24 h (IL-2) or 72 h (IFN-γ, TNF-α and IL-17A) culture supernatants of splenocytes from vaccinated C57BL/6 mice, after restimulation with the PPE44 MHC Class II-restricted synthetic peptide spanning amino acids 1–20 (PPE44[1–20]) or the recombinant PPE44 protein (rPPE44). RPMI, non-stimulated cells. ID, intradermally. IM, intramuscularly. 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; **p < 0.005.

Mentions: The production of IFN-γ, IL-2, TNF-α and IL-17A was evaluated in the culture supernatants of spleen cells isolated from vaccinated and control groups after restimulation with recombinant PPE44 or the PPE441–20 peptide. We have previously described that PPE441–20 is an immunodominant T CD4+ epitope recognized after BCG immunization, as well as after DNA vaccination [27]. As shown in Figure 2, PPE44-specific IFN-γ and IL-2 levels measured in the spleen of BCG/pDNA-PPE44 (ID) co-vaccinated C57BL/6 mice were greatly increased and significantly higher than the levels measured in mice of the control groups immunized with BCG alone or with a combination of BCG with a non-coding, empty pDNA vector. The levels induced by the BCG/pDNA-PPE44 combination were also significantly higher than the levels induced after three intramuscular pDNA-PPE44 administrations. TNF-α could be detected in cultures stimulated with recombinant PPE44 protein, but not with PPE441–20 peptide. In addition, increased TNF-α levels were observed in BCG/pDNA-PPE44 immunized mice compared to the levels achieved after vaccination with BCG, BCG combined to non-coding pDNA or intramuscular vaccination with pDNA-PPE44. Finally, no significant differences in specific IL-17A levels were observed between the different experimental groups.


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)

Specific Th1-type cytokine production induced by BCG/pDNA co-vaccination. IFN-γ, IL-2, TNF-α and IL-17A levels (pg/mL) were measured by ELISA in 24 h (IL-2) or 72 h (IFN-γ, TNF-α and IL-17A) culture supernatants of splenocytes from vaccinated C57BL/6 mice, after restimulation with the PPE44 MHC Class II-restricted synthetic peptide spanning amino acids 1–20 (PPE44[1–20]) or the recombinant PPE44 protein (rPPE44). RPMI, non-stimulated cells. ID, intradermally. IM, intramuscularly. 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; **p < 0.005.
© Copyright Policy
Related In: Results  -  Collection

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

vaccines-02-00181-f002: Specific Th1-type cytokine production induced by BCG/pDNA co-vaccination. IFN-γ, IL-2, TNF-α and IL-17A levels (pg/mL) were measured by ELISA in 24 h (IL-2) or 72 h (IFN-γ, TNF-α and IL-17A) culture supernatants of splenocytes from vaccinated C57BL/6 mice, after restimulation with the PPE44 MHC Class II-restricted synthetic peptide spanning amino acids 1–20 (PPE44[1–20]) or the recombinant PPE44 protein (rPPE44). RPMI, non-stimulated cells. ID, intradermally. IM, intramuscularly. 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; **p < 0.005.
Mentions: The production of IFN-γ, IL-2, TNF-α and IL-17A was evaluated in the culture supernatants of spleen cells isolated from vaccinated and control groups after restimulation with recombinant PPE44 or the PPE441–20 peptide. We have previously described that PPE441–20 is an immunodominant T CD4+ epitope recognized after BCG immunization, as well as after DNA vaccination [27]. As shown in Figure 2, PPE44-specific IFN-γ and IL-2 levels measured in the spleen of BCG/pDNA-PPE44 (ID) co-vaccinated C57BL/6 mice were greatly increased and significantly higher than the levels measured in mice of the control groups immunized with BCG alone or with a combination of BCG with a non-coding, empty pDNA vector. The levels induced by the BCG/pDNA-PPE44 combination were also significantly higher than the levels induced after three intramuscular pDNA-PPE44 administrations. TNF-α could be detected in cultures stimulated with recombinant PPE44 protein, but not with PPE441–20 peptide. In addition, increased TNF-α levels were observed in BCG/pDNA-PPE44 immunized mice compared to the levels achieved after vaccination with BCG, BCG combined to non-coding pDNA or intramuscular vaccination with pDNA-PPE44. Finally, no significant differences in specific IL-17A levels were observed between the different experimental groups.

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