The global Zika virus (ZIKV) outbreak and its link to fetal and newborn
microcephaly and severe neurological complications in adults call for the
urgent development of ZIKV vaccines. Arizona State University researchers,
led by Ming Yang, developed a subunit vaccine based on the ZIKV envelope (E)
protein and investigated its immunogenicity in mice.
Expression of ZIKV E (zE) in tobacco (Nicotiana benthamiana) resulted in
rapid accumulation in plant leaves. Biochemical analysis revealed that
plant-produced ZIKV E (PzE) exhibited specific binding to a panel of
monoclonal antibodies that recognize various zE conformational epitopes.
Furthermore, the PzE can be purified to >90% homogeneity with a one-step
Two doses of PzE drew out both potent zE-specific antibody and cellular
immune responses in mice. Most importantly, the concentration of zE-specific
and neutralizing antibodies exceeded the threshold and correlates with
protective immunity against multiple strains of ZIKV.
These results demonstrate the feasibility of plant-produced ZIKV protein
antigen as effective, safe and affordable vaccines against ZIKV.