The Zika virus, a flavivirus with devastating consequences for babies born of infected mothers, has garnered worldwide attention. Because of the dramatic and potentially deadly consequences of infection on unborn babies, researchers around the world have been scrambling to create an effective vaccine against the virus, particularly for areas where the infection is endemic, such as Brazil. Recently, researchers from Arizona State University (ASU) made great strides towards this goal, creating the world’s first plant-based Zika vaccine, which “could be more potent, safer, and cheaper to produce than any other efforts to date,” according to a press release
on the research.
Led by ASU Biodesign Institute scientist Qiang “Shawn” Chen, PhD, the researchers from ASU utilized a key protein in the Zika virus, DIII, to develop this new vaccine. Dr. Chen elaborated on this protein in the press release, stating, “All flaviviruses have the envelope protein on the outside part of the virus. It has three domains. The domain III has a unique stretch of DNA for the Zika virus, and we exploited this to generate a robust and protective immune response that is unique for Zika.”
The team “first grew the envelope protein in bacteria, and then, switched to prepare the DIII protein domain in tobacco plants.” Immunization experiments were performed in mice after the team had developed enough material. These experiments elicited cellular and antibody immune responses in the mice which conferred 100% protection again multiple strains of the Zika virus in mouse challenge.
Of course, working in the confines of the laboratory without contributing factors will yield slightly different results than in the real world. Other vaccines that other researchers are developing around the world have also produced positive results in lab tests; however, prior exposure to other flaviviruses, as is many times the case in real-world settings, can have unwanted effects on vaccines that use the complete Zika envelope protein for their vaccine. Dr. Chen explained in the press release, “When you make the full native envelope protein as the basis for a vaccine, it will induce antibodies against DI, DII and the DIII domains of the protein. Those who have been prior exposed to DI and DII of other members of the Zika virus family may be prone to developing very bad symptoms, or in some cases, fatalities for dengue.”