Navegando por Palavras-chave "Recombinant-Protein"

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    Imunogenicidade de diferentes candidatos e estratégias vacinais para os vírus Zika e Chikungunya
    (Universidade Federal de São Paulo (UNIFESP), 2021) Oliveira, Fernanda Caroline Coirada [UNIFESP]; Rosa, Daniela Santoro [UNIFESP]; Universidade Federal de São Paulo
    Arbovirus infections such as those caused by Zika virus (ZIKV) and Chikungunya virus (CHIKV) are responsible for a large number of cases with considerable severity and morbidity. So far, there are no vaccines or specific medications available against these arboviruses. The envelope protein (E) of ZIKV and CHIKV is the most abundant on the viral surface and responsible for the binding and fusion process with the target cell membrane. Furthermore, it is the main target of neutralizing antibodies being an important antigen candidate for vaccine development. DNA vaccines are very promising, as they are able to elicit both humoral and cellular immune responses, however, they have limited immunogenicity in humans. In recent years, several strategies have been developed in order to increase the immunogenicity of this vaccine platform, such as antigen targeting to dendritic cells (DCs) subpopulations, association with in vivo electroporation and heterologous prime-boost immunization. In the present work, we produced the recombinant protein E2CHIKVΔTM, and also scFV and pVAX DNA vaccines encoding the same antigen and compared the immunogenicity after homologous or heterologous prime-boost immunization. We observed that heterologous primeboost immunization was able to induce high antibody titers with neutralizing capacity, as well as specific IFN-γ producing cells and polyfunctional CD4+ and CD8+ T cell responses. In addition, we mapped the most immunogenic epitopes along the E2CHIKV protein and identified 14 potential epitopes, with CHIKV (361-374) being the immunodominant. Finally, we evaluated the influence of different adjuvants (poly (I:C), Addavax, Alhydrogel, AS03 and Quil A) on the immune response. We observed that mice immunized with recombinant E2CHIKVDTM combined with AS03 presents the highest humoral response with neutralizing capacity. Regarding ZIKV, we generated different vaccine candidates encoding ZIKV (EZIKV, EDI/IIZIKV and EDIIIZIKV) and CHIKV (E2CHIKV) viral envelope proteins and evaluated different vaccination strategies in a preclinical model. We produced DNA vaccines encoding a single chain variable fragment (scFVs) fused to ZIKV antigens to target it to dendritic cells. In addition, DNA vaccines (pVAX) encoding the same antigens without DC-targeting were produced and the induced specific immune response were compared. We observed that immunization of C57BL/6 mice with the different constructs was able to induce specific antibodies that specifically recognize the ZIKV and neutralize the infection. Immunization with the pVAX-EZIKV DNA vaccine was able to induce higher antibody titers when compared to scFv immunization. Furthermore, immunization with the constructs was able to induce polyfunctional CD4+ and CD8+ T lymphocytes and specific IFN-γ producing cells. The epitope mapping revealed that the peptides ZIKV (E1-20) and ZIKV (E51-70) contained in EDI/II domain and the peptides ZIKV (E351-370) and ZIKV (E361-380) contained in the domain protein EDIII were the most immunogenic. Taking together, our results demonstrated that the different strategies tested were efficient to induce humoral and cellular immune responses against ZIKV and CHIKV, thus opening new perspectives for the development of vaccine candidates.