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Protective Efficacy in Sheep of Adenovirus-Vectored Vaccines against Bluetongue Virus Is Associated with Specific T Cell Responses.

Martín V, Pascual E, Avia M, Peña L, Valcárcel F, Sevilla N - PLoS ONE (2015)

Bottom Line: Sheep vaccinated with Ad5-BTV-VP2 and Ad5-BTV-VP7 or only with Ad5-BTV-VP7 and challenged with BTV showed mild disease symptoms and reduced viremia.This partial protection was achieved in the absence of neutralizing antibodies but strong BTV-specific CD8+ T cell responses in those sheep vaccinated with Ad5-BTV-VP7.These data indicate that rAd5 is a suitable vaccine vector to induce T cell immunity during BTV vaccination and provide new data regarding the relevance of T cell responses in protection during BTV infection.

View Article: PubMed Central - PubMed

Affiliation: Centro de Investigación en Sanidad Animal (CISA-INIA), Instituto Nacional de Investigación Agraria y Alimentaria, Valdeolmos, Madrid, Spain.

ABSTRACT
Bluetongue virus (BTV) is an economically important Orbivirus of the Reoviridae family that causes a hemorrhagic disease in ruminants. Its control has been achieved by inactivated-vaccines that have proven to protect against homologous BTV challenge although unable to induce long-term immunity. Therefore, a more efficient control strategy needs to be developed. Recombinant adenovirus vectors are lead vaccine candidates for protection of several diseases, mainly because of their potency to induce potent T cell immunity. Here we report the induction of humoral and T-cell mediated responses able to protect animals against BTV challenge by recombinant replication-defective human adenovirus serotype 5 (Ad5) expressing either VP7, VP2 or NS3 BTV proteins. First we used the IFNAR(-/-) mouse model system to establish a proof of principle, and afterwards we assayed the protective efficacy in sheep, the natural host of BTV. Mice were completely protected against BTV challenge, developing humoral and BTV-specific CD8+- and CD4+-T cell responses by vaccination with the different rAd5. Sheep vaccinated with Ad5-BTV-VP2 and Ad5-BTV-VP7 or only with Ad5-BTV-VP7 and challenged with BTV showed mild disease symptoms and reduced viremia. This partial protection was achieved in the absence of neutralizing antibodies but strong BTV-specific CD8+ T cell responses in those sheep vaccinated with Ad5-BTV-VP7. These data indicate that rAd5 is a suitable vaccine vector to induce T cell immunity during BTV vaccination and provide new data regarding the relevance of T cell responses in protection during BTV infection.

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VP7-specific T cell responses in vaccinate sheep.PBMCs were purified from blood of vaccinated and control sheep at D30 post-vaccination (day of challenge), D7 pc and D15 pc, and stimulated with VP7 protein. Cells were stained for surface CD8 or CD4 and intracellular IFN-γ and analysed by flow cytometry. The percentage of CD8+ or CD4+ T cells producing IFN-γ after subtracting the background of the assay (response to RMPI medium) is indicated. Each dot corresponds to individual animals. Bars indicate the average of all animals. The asterisks indicate statistically significant with a p value of < 0.005 (Mann-Whitney U test).
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pone.0143273.g007: VP7-specific T cell responses in vaccinate sheep.PBMCs were purified from blood of vaccinated and control sheep at D30 post-vaccination (day of challenge), D7 pc and D15 pc, and stimulated with VP7 protein. Cells were stained for surface CD8 or CD4 and intracellular IFN-γ and analysed by flow cytometry. The percentage of CD8+ or CD4+ T cells producing IFN-γ after subtracting the background of the assay (response to RMPI medium) is indicated. Each dot corresponds to individual animals. Bars indicate the average of all animals. The asterisks indicate statistically significant with a p value of < 0.005 (Mann-Whitney U test).

Mentions: To evaluate VP7-specific T cell responses, PBMCs from vaccinated and control sheep were taken at D30 post-vaccination (day of challenge), D7 pc and D15 pc, and the cellular immune responses against BTV was analysed by intracellular IFN-γ staining. In vaccinated sheep (groups #1 and # 2), a statistically significant (p< 0.05, Mann-Whitney U test) percentage of CD8+ T cells responded to BTV stimulation in vitro producing IFN-γ (Fig 7) at D30 post-vaccination. Interestingly, at D7pc the VP7-specific CD8+ T cell response in vaccinated groups was also significantly (p < 0.05, Mann-Whitney U test) higher than in control groups (average of 1.4 ± 0.6 in Ad5-DsRed treated sheep versus 4.2 ± 0.5 in group#1 and 3.8 ± 0.5 in group #2). By D15pc all groups showed similar levels of CD8+ T cells producing IFN-γ. Thus, this data suggest that adenovirus expressing VP7 vaccination can rapidly (by D30 post-vaccination) elicit an efficient (measured by their capacity to produce IFN-γ) ex vivo detectable CD8+ T cells responses.


Protective Efficacy in Sheep of Adenovirus-Vectored Vaccines against Bluetongue Virus Is Associated with Specific T Cell Responses.

Martín V, Pascual E, Avia M, Peña L, Valcárcel F, Sevilla N - PLoS ONE (2015)

VP7-specific T cell responses in vaccinate sheep.PBMCs were purified from blood of vaccinated and control sheep at D30 post-vaccination (day of challenge), D7 pc and D15 pc, and stimulated with VP7 protein. Cells were stained for surface CD8 or CD4 and intracellular IFN-γ and analysed by flow cytometry. The percentage of CD8+ or CD4+ T cells producing IFN-γ after subtracting the background of the assay (response to RMPI medium) is indicated. Each dot corresponds to individual animals. Bars indicate the average of all animals. The asterisks indicate statistically significant with a p value of < 0.005 (Mann-Whitney U test).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664254&req=5

pone.0143273.g007: VP7-specific T cell responses in vaccinate sheep.PBMCs were purified from blood of vaccinated and control sheep at D30 post-vaccination (day of challenge), D7 pc and D15 pc, and stimulated with VP7 protein. Cells were stained for surface CD8 or CD4 and intracellular IFN-γ and analysed by flow cytometry. The percentage of CD8+ or CD4+ T cells producing IFN-γ after subtracting the background of the assay (response to RMPI medium) is indicated. Each dot corresponds to individual animals. Bars indicate the average of all animals. The asterisks indicate statistically significant with a p value of < 0.005 (Mann-Whitney U test).
Mentions: To evaluate VP7-specific T cell responses, PBMCs from vaccinated and control sheep were taken at D30 post-vaccination (day of challenge), D7 pc and D15 pc, and the cellular immune responses against BTV was analysed by intracellular IFN-γ staining. In vaccinated sheep (groups #1 and # 2), a statistically significant (p< 0.05, Mann-Whitney U test) percentage of CD8+ T cells responded to BTV stimulation in vitro producing IFN-γ (Fig 7) at D30 post-vaccination. Interestingly, at D7pc the VP7-specific CD8+ T cell response in vaccinated groups was also significantly (p < 0.05, Mann-Whitney U test) higher than in control groups (average of 1.4 ± 0.6 in Ad5-DsRed treated sheep versus 4.2 ± 0.5 in group#1 and 3.8 ± 0.5 in group #2). By D15pc all groups showed similar levels of CD8+ T cells producing IFN-γ. Thus, this data suggest that adenovirus expressing VP7 vaccination can rapidly (by D30 post-vaccination) elicit an efficient (measured by their capacity to produce IFN-γ) ex vivo detectable CD8+ T cells responses.

Bottom Line: Sheep vaccinated with Ad5-BTV-VP2 and Ad5-BTV-VP7 or only with Ad5-BTV-VP7 and challenged with BTV showed mild disease symptoms and reduced viremia.This partial protection was achieved in the absence of neutralizing antibodies but strong BTV-specific CD8+ T cell responses in those sheep vaccinated with Ad5-BTV-VP7.These data indicate that rAd5 is a suitable vaccine vector to induce T cell immunity during BTV vaccination and provide new data regarding the relevance of T cell responses in protection during BTV infection.

View Article: PubMed Central - PubMed

Affiliation: Centro de Investigación en Sanidad Animal (CISA-INIA), Instituto Nacional de Investigación Agraria y Alimentaria, Valdeolmos, Madrid, Spain.

ABSTRACT
Bluetongue virus (BTV) is an economically important Orbivirus of the Reoviridae family that causes a hemorrhagic disease in ruminants. Its control has been achieved by inactivated-vaccines that have proven to protect against homologous BTV challenge although unable to induce long-term immunity. Therefore, a more efficient control strategy needs to be developed. Recombinant adenovirus vectors are lead vaccine candidates for protection of several diseases, mainly because of their potency to induce potent T cell immunity. Here we report the induction of humoral and T-cell mediated responses able to protect animals against BTV challenge by recombinant replication-defective human adenovirus serotype 5 (Ad5) expressing either VP7, VP2 or NS3 BTV proteins. First we used the IFNAR(-/-) mouse model system to establish a proof of principle, and afterwards we assayed the protective efficacy in sheep, the natural host of BTV. Mice were completely protected against BTV challenge, developing humoral and BTV-specific CD8+- and CD4+-T cell responses by vaccination with the different rAd5. Sheep vaccinated with Ad5-BTV-VP2 and Ad5-BTV-VP7 or only with Ad5-BTV-VP7 and challenged with BTV showed mild disease symptoms and reduced viremia. This partial protection was achieved in the absence of neutralizing antibodies but strong BTV-specific CD8+ T cell responses in those sheep vaccinated with Ad5-BTV-VP7. These data indicate that rAd5 is a suitable vaccine vector to induce T cell immunity during BTV vaccination and provide new data regarding the relevance of T cell responses in protection during BTV infection.

Show MeSH
Related in: MedlinePlus