Efeito do peptídeo EL28 como adjuvante da vacina DENV3E

Abstract

EL28 peptide is an intracellular peptide thar appears to have an endogenous contribution to the biological activity of IFN-γ. In a previous study, Monte et al., the EL28 peptide showed an ability to increase the titer of anti-BSA IgG antibodies in mice. In addition, the EL28 peptide activated T CD8 cells proliferation. The results suggest that the EL28 peptide has a potential as an immunostimulatory peptide and coud be used as an adjuvant in vaccine formulation. Objectives: In this study, we accessed the ability of EL28 peptide to boost the immune response induced for the DENV3E subunit vaccine, in this study called for pE, a truncated construct of the DENV3 glycoprotein E transmembrane region. Materials and Methods: Female C57/Bl6 mice were immunized with a combination of the pE vaccine and the EL28 peptide. After three immunizations, the animals were challenged with type 3 dengue virus. The expression levels of T CD8 and CD4 T cell expression, central and effector memory cells and IFN-γ cytokine expression and of the nonstructural viral protein 3 (NS3), for flow cytometry to assess the immunostimulatory effects of EL28. Cytokine secretion was also assessed by ELISA. In addition, the Evans Blue dye assay was performed to assess whether there was a change in vascular permeability between the control and infected groups. Results: pE+EL28 vaccination schedule was able to reverse thrombocytopenia induced by DENV3 infection, as well as, stimulated proliferation of total spleen cells and of CD8+ and CD4+ T-type lymphocytes. However, our infection model was not able to induce other signs of the disease, such as hemoconcentration and increased vascular permeability. Conclusion: When compare all experimental groups, EL28 showed no advantage as an adjuvant to the pE vaccine. Further studies should be conducted in order to adapt the immunization scheme to the experimental model studied.