Recombinant Dengue Virus serotype 1 DIII envelope protein [His]

Our group has developed a subunit vaccine candidate against Dengue virus (DENV) based on two different viral regions, the domain III of the envelope protein and the capsid protein. The chimeric proteins for each serotype (DIIIC1-4), aggregated with the oligodeoxynucleotide 39 M, form the tetravalent formulation named Tetra DIIIC. Tetra DIIIC induces a protective immune response in mice when it is inoculated by intraperitoneal route. However, if children are the main targets for a DENV vaccine, then aneedle- free route of administration should be attractive and advantageous. In this study, we evaluated for the first time, in vivo, a vaccine candidate against DENV based on recombinant proteins using the intranasal route. After three doses of Tetra DIIIC in mice, we measured the humoral immune response against the four DENV serotypes and the corresponding recombinant proteins. Moreover, the functionality of these antibodies was evaluated through a plaque reduction neutralization test. Finally, to assess the cellular immune response induced, we measured the IFN-c-levels secreted by spleen cells after in vitro stimulation with DENV. The results presented in this study indicate that the intranasal immunization with Tetra DIIIC favors the generation of DENV-specific cell-mediated immunity. On the other hand, the immunization using intraperitoneal and intranasal routes, simultaneously, generate functional antibodies (anti-DIIIC and anti-DENV) and an in vitro response of IFN-gamma secretion.

Dengue (DEN) is the most important mosquito-borne viral disease, with a major impact on global health and economics, caused by four serologically and distinct viruses termed DENV-1 to DENV-4. Currently, there is no licensed vaccine to prevent DEN. We have developed a live attenuated tetravalent DENV vaccine candidate (TDV) (formally known as DENVax) that has shown promise in preclinical and clinical studies and elicits neutralizing antibody responses to all four DENVs. As these responses are lowest to DENV-4 we have used the AG129 mouse model to investigate the immunogenicity of monovalent TDV4 or tetravalent TDV vaccines, and their efficacy against lethal DENV-4 challenge. Since the common backbone of TDV is based on an attenuated DENV-2 strain (TDV-2) we also tested the efficacy of TDV-2 against DENV-4 challenge. Single doses of the tetravalent or monovalent vaccines elicited neutralizing antibodies, anti-NS1 antibodies, and cellular responses to both envelope and nonstructural proteins. All vaccinated animals were protected against challenge at 60 days post-immunization, whereas all control animals died. Investigation of DENV-4 viremias post-challenge showed that only the control animals had high viremias on day 3 post-challenge, whereas vaccinated mice had no detectable viremia. Overall, these data highlight the excellent immunogenicity and efficacy profile of our candidate dengue vaccine in AG129 mice. (C) 2014 Elsevier Ltd. All rights reserved.