New Live Attenuated Zika Virus Vaccine
Abstract
There are many types of vaccines in use, representing different strategies to try to reduce virulence but retain the ability to induce beneficial and protective immune responses. The most popular and traditional strategies are through inactivating or attenuating organisms. There are several ways to accomplish each strategy. A live attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable or "live" to replicate and inducing protective immune responses without causing disease in the host. The induced protective immune responses could protect the vaccinated individuals against severe disease or even infection in the future. There are three classical ways to produce live attenuated vaccine. The first one is by searching naturally occurring related organisms that are virulent in their natural host(s) but avirulent in humans, which include host range restricted organisms or naturally occurring avirulent strains. The second one is through multiple rounds of growth of virulent organisms in tissue culture or harsh physical conditions that could weaken the virulence of the organisms. The third one is through genetic manipulation of organisms to reduce virulence and/or reproduction. Natural viruses normally need to reproduce thousands of times during infection to cause disease. Reduced reproduction of viruses through attenuation makes them unable to create nearly enough copies of viruses to cause disease. At the same time, this reduced reproduction of viruses is enough to induce protective immune responses, such as memory antibody responses and T and B cellular immune responses, to keep the body from getting the viral infection in the future. In our proposed study, we will make use of RNA interference (RNAi) technology to silence or post-transcriptionally regulate viral gene expression by interacting with specific viral messenger RNAs for reducing viral reproduction/virulence. RNAi is a post-transcriptional gene silencing mechanism and has become a feasible strategy against a variety of viral infections since its discovery in 1994. Two types of small RNAs, namely small interfering RNA (siRNA) and microRNA (miRNA or miR), are the central players in RNAi process. The miRNAs are a small non-coding RNA molecule, which functions to silence or post-transcriptionally regulate gene expression by interacting with messenger RNAs and targeting them for degradation. Viral vector-expressed artificial miRNAs (amiR) technology is more effective in genetically manipulating viral genome to silence viral gene expression and reduce viral reproduction. The amiR technology take great advantage of the intrinsic nature of the processing stages of the miRNA biogenesis pathway that direct highly efficient RNA silencing of the targeted gene. In our proposed study, we will design an amiR-93 to target the non-structural protein 5 (NS5) of Zika virus (ZIKV), insert this amiR-93 into the specific site of the non-coding sequence of the viral genome, and produce the whole infectious ZIKV cDNA clone containing amiR-93. This clone will be transfected into permissive cells, such as Vero cells, to produce genetically manipulated ZIKV, which potentially is live self-attenuated Zika virus (SAZV) vaccine. The efficacy of the developed live SAZV vaccine will be investigated in recently established A129 (lacking interferon alpha/beta receptors) and AG129 (lacking interferon alpha/beta and gamma receptors) mouse models of ZIKV infection. The ZIKV-specific cellular and humoral immune responses during infection, immunization, and post-challenge will be determined by ZIKV antigen-specific Enzyme-linked immunosorbent assay (ELISA), B cell and cytokine Enzyme-Linked ImmunoSpot (ELISpot), multiparametric flow cytometry, cytotoxic T cell (CTL) assay, and cytokine analysis. The success of this research will not only provide a candidate prophylactic and therapeutic ZIKV vaccine for further clinical evaluatio
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 29, 2018
- Source ID
- W81XWH1810387
Entities
People
- Mingtao Zeng
Organizations
- Texas Tech University Health Sciences Center
- United States Army