Desenvolvimento de candidatos vacinais contra o vírus zika utilizando a proteína do envelope viral, recombinante, funcionalizada ou não em nanobastões de ouro

Abstract

For decades, infections caused by the Zika virus (ZIKV) were neglected because of their usual mild symptoms and limited number of cases. In recent years, however, the rapid spread of ZIKV and its unexpected link to congenital Zika syndrome and Guillain-Barré syndrome have turned the virus into an emerging public health problem of global concern, for which no vaccine is available. Among the areas that present themselves in an attractive way and with great potential for use in the development of efficient vaccine platforms, nanotechnology has gained prominence, especially gold nanoparticles, for their unique optical and chemical properties that allow their binding to organic molecules, such as proteins, including their use as vaccine carriers. In the present work, we show the heterologous expression and purification of the Zika virus envelope protein (ZIKV-E), the functionalization of commercial gold nanorods (Nanopartz) with the produced protein and the characterization of the experimental vaccine produced. Finally, we evaluated the cellular and humoral immune response generated after immunization of BALB/c mice with the produced protein and with the protein-bound gold nanorods, each combined with the vaccine adjuvants monophosphoryl lipid A (LPS analog) and 7DW8- 5 (α-GalCer analogue) and also with alum. For this, we produced in E. coli BL21 and purified a recombinant version of the ZIKV protein E (ZIKV-E) truncated in its C-terminal portion. The purified protein was recognized by Anti-His and Panflavi 4G2 antibodies in western-blot assays. Subsequently, commercial gold nanorods were functionalized with the recombinant protein produced and the tool characterized by UV/Vis spectroscopy, evaluation of the zeta potential, evaluation of the hydrodynamic radius and by fluorometry, confirming the binding of the protein to the surface of gold nanorods. Upon mice immunization with the experimental vaccines, high levels of anti-ZIKV neutralizing antibodies were detected. Besides that, experimental vaccines were able to induce the activation of immune system cells from immunized animals with polyfunctional activity of secretion of important cytokines in a context of viral infection and activation of memory cells. We observed an increase in IFN-γ secreted by specific CD4+ and CD8+ lymphocytes in the group immunized with the complete experimental vaccine, in addition, we evaluated the presence of the CD127 marker, in populations with the effector (CD44+) and central (CD44+ CD62L+) memory phenotype. Together, our results are significant, and the immunogen promising for further trials. The next steps of this work include evaluating the protection of this experimental vaccine in the face of a challenge with ZIKV.