Study of the adjuvant effect of the NS3 peptide in the immune response of mice vaccinated with inactivated Zika Virus

Author(s)

Jonathan Ballico de Moraes

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2018-12-12

Examining board members

Benedito Antonio Lopes da Fonseca; Flávio Guimarães da Fonseca; Simone Kashima Haddad

• Advisor: Benedito Antonio Lopes da Fonseca

Abstract

Zika Fever is a disease that affects many people in tropical and subtropical countries. The etiologic agent is Zika Virus (ZIKV), a single-stranded RNA flavivirus, transmitted mostly by Aedes mosquitoes, but sexual, congenital and blood transfusion transmission has also been reported. Due to the possible association of ZIKV to microcephaly and Guillain-Barré Syndrome, it is necessary to develop strategies for disease prevention. Among them, the best prophylactic measure is vaccination. The non-structural protein NS3 has been shown to stimulate cellular immunity response against others flaviviruses, and such activity has been used as a target against other flaviviruses infection. In this context, the aim of this project is to test the efficiency of NS3, in combination with the inactivated virus, to produce a vaccine capable of developing full protection against viral infection. The NS3 sequence was cloned into the pET-26b vector, expressed in E. coli Rosetta and purified by nickel column affinity chromatography. The complete inactivation of ZIKV was performed by addition of 0.05% formaldehyde and incubation for 3 days. Vaccine combinations of NS3 and inactivated virus were inoculated into 129 Sv/Ev and A129 mice on days 0 and 14. On day 21, vaccinated A129 mice were challenged with wild ZIKV and analyzed for weight loss and survival by 21 days. Mice vaccinated with NS3 and inactivated virus, in the same vaccine formulation, had 100% protection against infectious ZIKV. Whole blood and spleen cells were collected from 129 Sv/Ev and A129 mice after 21 days of new immunization. The production of specific and neutralizing antibodies against ZIKV was evaluated by Imunnofluorescence, ELISA and PRNT, showing that animals immunized with the vaccine formulation \"virus inactivated with NS3\" increased the antibodies\' level against the virus, but no virus neutralization was detected in any immunized group. The cytokine profile expressed by spleen lymphocytes, analyzed by FACS, suggests that NS3 participates in modulation for a Th1 response. This approach gave us the opportunity to evaluate this vaccinal combination that was shown to be able to prevent infection with ZIKV in susceptible mice (AU)

• FAPESP's process: 16/26145-3 - Effect of peptide derived from NS3 protein in the immune response of mice inoculated with inactivated Zika virus vaccine
• Grantee: Jonathan Ballico de Moraes
• Support Opportunities: Scholarships in Brazil - Master