Development of a tetravalent vaccine against the four serotypes of the Dengue virus using VLPs technology

Abstract

Dengue is a disease of viral etiology, triggered by the Dengue virus (DENV) of the genus Flavivirus, of the Flaviviridae family. Regarding variability and pathogenicity, four antigenically distinct serotypes are known, DENV-1, DENV-2, DENV-3 and DENV-4. The disease presents symptoms that can be considered classic with severe headache and muscle and joint pain, for example, lasting 5 to 7 days, with the period of viremia extending until the 6th day after the onset of fever. In the most severe form, it can manifest as dengue hemorrhagic fever, which presents initial symptoms similar to the classic form of the disease, but quickly evolves into highly relevant hemorrhagic manifestations, with the possibility of cavitary effusions, hemodynamic instability, and shock. As a form of prevention, we seek to develop safe and effective vaccines against dengue serotypes, as it is of paramount importance for public health worldwide, especially for endemic countries, like Brazil. However, to avoid the formation of a secondary immune response caused by infection with different serotypes, the target antigen must prevent the immune response from presenting cross-reactivity between DENV serotypes, as well as with other Flaviviruses, such as Zika virus. It is worth noting that VLPs (virus-like-particles) are nanoparticles composed of non-infectious proteins with preservation of the original structure, enabling the interaction of cells with a non-infectious and, therefore, safe viral particle. The use of VLPs brings many benefits to vaccine formulation, such as improving the modulation of the immune response, being involved in stimulating adaptive and humoral immunity. In this sense, the objective of this work is to develop a tetravalent vaccine against the four DENV serotypes using VLP technology as delivery systems for the E-III proteins of the viral serotypes. The VLPs that we will use in this project have already been produced by our research group and are being used for other targets, such as the new Coronavirus, Zika and Chikungunya viruses, and have demonstrated excellent results. Regarding the production of DENV E-DIII proteins, these will be based on target genes most circulating in Brazil, selected from GenBank and sent to be synthesized by Geneart. Production and purification will be carried out according to protocols already standardized in our laboratory and continually adapted through bibliographical research. With regard to measuring the immunogenic capacity of vaccine formulations, isogenic mice of the C57BL/6 lineage, previously approved by the Animal Use Ethics Committee (CEUA no. 4133290720) of ICB-USP, will be used. Thus, the best vaccine formulations will be analyzed for efficacy by vaccination and testing of mice challenged against DENV serotypes.