Improving Vaccine Design For Viral Diseases Using Modified Antigens And Vectors

Loading...
Thumbnail Image
Degree type
Doctor of Philosophy (PhD)
Graduate group
Cell & Molecular Biology
Discipline
Subject
Antibody
Envelope
HIV
mRNA
Vaccine
Zika
Virology
Funder
Grant number
License
Copyright date
2018-02-23T20:17:00-08:00
Distributor
Related resources
Contributor
Abstract

Two of the principal challenges facing vaccine design today are how to generate protective antibody responses against viruses that have evolved sophisticated strategies to evade the humoral immune system and how to more rapidly and effectively produce vaccines to address emerging epidemics. In this regard, we explored multiple strategies to improve vaccine design for HIV-1 and Zika virus. In one approach, we derived CD4-independent variants of HIV-1 envelope (Env) with the hypothesis that such Envs would expose conserved epitopes that may be targets of protective, non-neutralizing antibodies. We characterized the biological and structural properties of two CD4-independent Env clones and found that they exhibited significantly greater exposure of a relatively conserved, linear epitope in the second variable loop (V2) that had previously been associated with decreased risk of infection in a clinical HIV-1 vaccine trial. This epitope was significantly more immunogenic in mice and nonhuman primates and, intriguingly, was associated with more rapid development of antibody-dependent cell-mediated cytotoxicity. In another approach, we designed mutations in the cytoplasmic tail of HIV-1 Env that were predicted to increase its cell surface expression and thus its immunogenicity in a vaccinia prime-protein boost vaccine protocol. We found that the highest level of surface expression was mediated by Envs with truncated cytoplasmic tails, and this was associated with higher levels of binding and neutralizing antibodies after vaccinia primes and protein boosts, respectively. These two studies revealed that modifications to HIV-1 Env immunogens are able to influence both the quality and magnitude of desirable antibody responses. Finally, we used a newly developed vaccine platform based on nucleoside-modified mRNA to design a vaccine against Zika virus. This vaccine, encoding the surface prM and E proteins, was potently immunogenic and elicited high and sustained titers of neutralizing antibodies in mice and nonhuman primates following a single intradermal immunization. We observed rapid and durable protection from Zika virus infection in mice and a high level of protection in monkeys challenged five weeks after vaccination. This vaccine thus represents a promising candidate for clinical use in controlling the spread of Zika virus.

Advisor
Drew Weissman
James A. Hoxie
Date of degree
2017-01-01
Date Range for Data Collection (Start Date)
Date Range for Data Collection (End Date)
Digital Object Identifier
Series name and number
Volume number
Issue number
Publisher
Publisher DOI
Journal Issue
Comments
Recommended citation