Design and efficacy evaluation of a DNA vaccine against zika virus in mice

Author(s)

Franciane Mouradian Emidio Teixeira

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2023-08-04

Examining board members

Maria Notomi Sato; Silvia Beatriz Boscardin; Roberto Dias Lins Neto; Ana Maria Carmona Ribeiro

• Advisor: Maria Notomi Sato; Isabelle Freire Tabosa Viana

Abstract

Congenital and postnatal outcomes of Zika virus (ZIKV) infection, added to its epidemiological relevance, highlight the importance for prophylactic vaccine strategies development and, to date, there is no vaccine licensed. In this project, we developed DNA vaccine formulations encoding to ZIKV premembrane/ membrane and envelope (E) proteins, aiming different optimization approaches to achieve adequate immunogenicity. A DNA vaccine candidate (described as ZK_&#914STP) using the tPA-SP (tissue plasminogen activator signal peptide) leader sequence to increase expression and secretion of synthesized proteins, with depletion of the stem anchoring region of the E protein was selected due higher immunogenicity. Immunization of immunocompetent C57BL/6 mice with ZK_&#914STP was able to induce ZIKV-specific IFN-ϒ-secreting splenic cells for up to three months and generation of neutralizing antibodies. Immunization with ZK_&#914STP in adult C57-IFNα/ß-/- mice contributed to protection against ZIKV challenge, with reduced viral load in the brain at 21 days post infection (dpi) in comparison to the control group (PBS). In addition, 42% of these animals showed a viral load below the detection limit. Anti-ZIKV IgG antibody titers decreased from the second month of vaccination, which compromised the protection of the offspring from immunized mothers for a period longer than two months. However, the immunization associated with the Alum adjuvant was able to increase the titers and duration of neutralizing antibodies, promoting a short- and long-term protective effect in adult mice. At the short term, viral load was undetectable in the brains of animals vaccinated at 10dpi. While at the long term, two-thirds of animals vaccinated, with or without an additional booster dose, showed a brain viral load below the detection limit at 10 dpi. In order to increase the expression of vaccine antigens, a system of nanoparticles (NPs) functionalized with cationic polymer brushes was developed, using the polymer poly(dimethylaminoethyl methacrylate) (PDMAEMA) to deliver plasmid DNA (pDNA). This system showed high affinity binding to pDNA with formation of cationic complexes and their 18 cellular internationalization. This approach also allowed cell transfection with efficiency comparable to commercial transfection systems, but without pronounced cytotoxic effect. Finally, this approach was efficient in transfecting the ZK_&#914STP candidate vaccine with ZIKV E protein expression. Taken together, the results point to a vaccine strategy that may be promising to protect against ZIKV infection and its adverse outcomes. As well as, the rational design for this formulation and delivery system based on polycationic NPs emerges as an innovative and potential strategy for other DNA and RNA vaccines. Offering support not only for genetic vaccines, but also for other immunotherapies. (AU)

• FAPESP's process: 18/18230-6 - Evaluation of the efficacy of the Zika Virus chimeric DNA vaccine and the lysosomal-associated membrane protein in mice
• Grantee: Franciane Mouradian Emidio Teixeira
• Support Opportunities: Scholarships in Brazil - Doctorate