Anti-Flavivirus Vaccines: Review of the Present Situation and Perspectives of Subunit Vaccines Produced in Escherichia coli

Abstract

This article aims to review the present status of anti-flavivirus subunit vaccines, both those at the experimental stage and those already available for clinical use. Aspects regarding development of vaccines to Yellow Fever virus, (YFV), Dengue virus (DENV), West Nile virus (WNV), Zika virus (ZIKV), and Japanese encephalitis virus (JEV) are highlighted, with particular emphasis on purified recombinant proteins generated in bacterial cells. Currently licensed anti-flavivirus vaccines are based on inactivated, attenuated, or virus-vector vaccines. However, technological advances in the generation of recombinant antigens with preserved structural and immunological determinants reveal new possibilities for the development of recombinant protein-based vaccine formulations for clinical testing. Furthermore, novel proposals for multi-epitope vaccines and the discovery of new adjuvants and delivery systems that enhance and/or modulate immune responses can pave the way for the development of successful subunit vaccines. Nonetheless, advances in this field require high investments that will probably not raise interest from private pharmaceutical companies and, therefore, will require support by international philanthropic organizations and governments of the countries more severely stricken by these viruses.

Solutions against emerging infectious and noninfectious human diseases through the application of baculovirus technologies

“…Despite the proven efficacy of the vaccine, it is based on attenuated viruses, vaccination is not recommended for persons older than 60 years or younger than 6 years of age, or for allergic and immunocompromised patients. Therefore, BEVS offers an alternative platform to develop immunogens that could be administered regardless of people's age or health status (Araujo et al 2020). Furthermore, a YF diagnosis can be performed with the E antigen expressed in High Five™ cells as a reagent to develop an immunoassay to detect specific antibodies in the serum of infected patients (Barros et al 2011).…”

Linear and Continuous Flavivirus Epitopes From Naturally Infected Humans

“…The most comprehensive mapping with the greatest number of identified linear B-cell immunoreactive peptides has been completed for the envelope protein (68 peptides), followed by the Ns1 protein (49 peptides). These proteins are considered to be the most immunogenic targets of the immune system and are therefore the main targets for antiviral drug research, biological marker identification, immunodiagnosis, vaccine candidate development, and studies of pathogenesis (Zakaria et al, 2018;Chong et al, 2019;Araujo et al, 2020). Fewer immunoreactive peptides have been described for the capsid (Byk and Gamarnik, 2016) and prM (Mackenzie et al, 1996) proteins; however, important immunoreactive peptides have still been described for these proteins.…”

Ocular Manifestations of West Nile Virus

“…There is, at present, no proven specific treatment or efficient vaccine for WNVI in humans [ 35 ]. Specific ophthalmic treatments that may be required include topical steroids and mydriatic agents for anterior uveitis, and peripheral retinal photocoagulation of retinal ischemic zones to prevent neovascularization.…”