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Gene Expression Driven by a Strong Viral Promoter in MVA Increases Vaccination Efficiency by Enhancing Antibody Responses and Unmasking CD8⁺ T Cell Epitopes.

Becker PD, Nörder M, Weissmann S, Ljapoci R, Erfle V, Drexler I, Guzmán CA - Vaccines (Basel) (2014)

Bottom Line: T cells recognizing determinants derived from late viral proteins have a clear disadvantage to proliferate during secondary responses.Although the Ag-expression from the natural promoter 7.5 (P7.5) and the mPH5 seemed similar, detailed analysis showed that mPH5 not only induces higher expression levels than P7.5 during early phase of infection, but also Ag turnover is enhanced.The strong overexpression during the early phase leads to broader CD8 T cell responses, while preserving the priming efficiency of stable Ags.

View Article: PubMed Central - PubMed

Affiliation: Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, D-38124 Braunschweig, Germany. pablo.becker@kcl.ac.uk.

ABSTRACT
Viral vectors are promising tools for vaccination strategies and immunotherapies. However, CD8⁺ T cell responses against pathogen-derived epitopes are usually limited to dominant epitopes and antibody responses to recombinant encoded antigens (Ags) are mostly weak. We have previously demonstrated that the timing of viral Ag expression in infected professional Ag-presenting cells strongly shapes the epitope immunodominance hierarchy. T cells recognizing determinants derived from late viral proteins have a clear disadvantage to proliferate during secondary responses. In this work we evaluate the effect of overexpressing the recombinant Ag using the modified vaccinia virus early/late promoter H5 (mPH5). Although the Ag-expression from the natural promoter 7.5 (P7.5) and the mPH5 seemed similar, detailed analysis showed that mPH5 not only induces higher expression levels than P7.5 during early phase of infection, but also Ag turnover is enhanced. The strong overexpression during the early phase leads to broader CD8 T cell responses, while preserving the priming efficiency of stable Ags. Moreover, the increase in Ag-secretion favors the induction of strong antibody responses. Our findings provide the rationale to develop new strategies for fine-tuning the responses elicited by recombinant modified vaccinia virus Ankara by using selected promoters to improve the performance of this viral vector.

No MeSH data available.


Related in: MedlinePlus

Cytokine production in an in vitro Ag presentation test by DCs infected with MVA-OVA. DCs were infected for 6 h with MVA-OVA P7.5 and MVA-OVA mPH5 at a MOI of 1 or 10. After infection, DCs were cultured with naïve CD4+ T cells from OT-II mice. At day 5 intracellular staining was carried out for IL-4 and IFN-γ. OVA peptide AA323–339 was used as a control.
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vaccines-02-00581-f005: Cytokine production in an in vitro Ag presentation test by DCs infected with MVA-OVA. DCs were infected for 6 h with MVA-OVA P7.5 and MVA-OVA mPH5 at a MOI of 1 or 10. After infection, DCs were cultured with naïve CD4+ T cells from OT-II mice. At day 5 intracellular staining was carried out for IL-4 and IFN-γ. OVA peptide AA323–339 was used as a control.

Mentions: The changes observed on activation markers prompted us to evaluate if Ag expression driven by different promoters also affects the Ag presentation capacity of DCs. To this end, Ag presentation by DCs infected with MVA-OVA P7.5 or MVA-OVA mPH5 was evaluated in vitro. Ag-specific CFSE-labelled CD8+ and CD4+ T cells (from OT-I and OT-II mice, respectively) were co-cultured with infected DCs and proliferation was assessed by the dilution of the fluorescent dye (Figure 4). A similarly strong CD8+ T cell proliferation was induced by DCs infected with MVA-OVA P7.5 and MVA-OVA mPH5 in a MOI-dependent manner (Figure 4A). However, proliferation of CD4+ T cells induced by MVA-OVA mPH5 was stronger than that promoted by MVA-OVA P7.5 (Figure 4B). Furthermore, CD4+ T cells stimulated in an Ag presentation assay showed higher levels of IL-4 and particularly IFN-γ production when using MVA-OVA mPH5 infected DCs, as compared to MVA-OVA P7.5 infected DCs (Figure 5).


Gene Expression Driven by a Strong Viral Promoter in MVA Increases Vaccination Efficiency by Enhancing Antibody Responses and Unmasking CD8⁺ T Cell Epitopes.

Becker PD, Nörder M, Weissmann S, Ljapoci R, Erfle V, Drexler I, Guzmán CA - Vaccines (Basel) (2014)

Cytokine production in an in vitro Ag presentation test by DCs infected with MVA-OVA. DCs were infected for 6 h with MVA-OVA P7.5 and MVA-OVA mPH5 at a MOI of 1 or 10. After infection, DCs were cultured with naïve CD4+ T cells from OT-II mice. At day 5 intracellular staining was carried out for IL-4 and IFN-γ. OVA peptide AA323–339 was used as a control.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494220&req=5

vaccines-02-00581-f005: Cytokine production in an in vitro Ag presentation test by DCs infected with MVA-OVA. DCs were infected for 6 h with MVA-OVA P7.5 and MVA-OVA mPH5 at a MOI of 1 or 10. After infection, DCs were cultured with naïve CD4+ T cells from OT-II mice. At day 5 intracellular staining was carried out for IL-4 and IFN-γ. OVA peptide AA323–339 was used as a control.
Mentions: The changes observed on activation markers prompted us to evaluate if Ag expression driven by different promoters also affects the Ag presentation capacity of DCs. To this end, Ag presentation by DCs infected with MVA-OVA P7.5 or MVA-OVA mPH5 was evaluated in vitro. Ag-specific CFSE-labelled CD8+ and CD4+ T cells (from OT-I and OT-II mice, respectively) were co-cultured with infected DCs and proliferation was assessed by the dilution of the fluorescent dye (Figure 4). A similarly strong CD8+ T cell proliferation was induced by DCs infected with MVA-OVA P7.5 and MVA-OVA mPH5 in a MOI-dependent manner (Figure 4A). However, proliferation of CD4+ T cells induced by MVA-OVA mPH5 was stronger than that promoted by MVA-OVA P7.5 (Figure 4B). Furthermore, CD4+ T cells stimulated in an Ag presentation assay showed higher levels of IL-4 and particularly IFN-γ production when using MVA-OVA mPH5 infected DCs, as compared to MVA-OVA P7.5 infected DCs (Figure 5).

Bottom Line: T cells recognizing determinants derived from late viral proteins have a clear disadvantage to proliferate during secondary responses.Although the Ag-expression from the natural promoter 7.5 (P7.5) and the mPH5 seemed similar, detailed analysis showed that mPH5 not only induces higher expression levels than P7.5 during early phase of infection, but also Ag turnover is enhanced.The strong overexpression during the early phase leads to broader CD8 T cell responses, while preserving the priming efficiency of stable Ags.

View Article: PubMed Central - PubMed

Affiliation: Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, D-38124 Braunschweig, Germany. pablo.becker@kcl.ac.uk.

ABSTRACT
Viral vectors are promising tools for vaccination strategies and immunotherapies. However, CD8⁺ T cell responses against pathogen-derived epitopes are usually limited to dominant epitopes and antibody responses to recombinant encoded antigens (Ags) are mostly weak. We have previously demonstrated that the timing of viral Ag expression in infected professional Ag-presenting cells strongly shapes the epitope immunodominance hierarchy. T cells recognizing determinants derived from late viral proteins have a clear disadvantage to proliferate during secondary responses. In this work we evaluate the effect of overexpressing the recombinant Ag using the modified vaccinia virus early/late promoter H5 (mPH5). Although the Ag-expression from the natural promoter 7.5 (P7.5) and the mPH5 seemed similar, detailed analysis showed that mPH5 not only induces higher expression levels than P7.5 during early phase of infection, but also Ag turnover is enhanced. The strong overexpression during the early phase leads to broader CD8 T cell responses, while preserving the priming efficiency of stable Ags. Moreover, the increase in Ag-secretion favors the induction of strong antibody responses. Our findings provide the rationale to develop new strategies for fine-tuning the responses elicited by recombinant modified vaccinia virus Ankara by using selected promoters to improve the performance of this viral vector.

No MeSH data available.


Related in: MedlinePlus