Amphiphilic block copolymer delivery of a DNA vaccine against Zika virus.

Zika virus (ZIKV) is a mosquito-borne flavivirus that was first discovered in 1947. Since then, outbreaks have been reported in tropical Africa, Southeast Asia, the Pacific Islands, and, in 2015, in the Americas. Since 2013, many countries have reported cases of microcephaly and other central nervous system malformation associated with ZIKV. Because the initial target population for a ZIKV vaccine is expected to be women of child-bearing age, including those who may be pregnant, it is necessary to develop safe, easily administered, and non-viral vaccines. Here, we show that a single tetrafunctional Amphiphilic Block Copolymer (ABC) delivers DNA that encodes the full natural sequence of prM-E, among other antigen designs tested, induces the highest antibody titer and neutralization activity against three divergent ZIKV isolates. Vaccination with a single tetrafunctional block copolymer delivering low dose (10 µg) DNA plasmid rapidly induces protection from detectable viremia during acute infection in mice challenged by ZIKV more than 7 months after their first vaccination and boosted 2 weeks before challenge. This use of tetrafunctional ABCs is a new approach to deliver DNA antigens against flaviviruses. The data demonstrate that DNA formulated by a tetrafunctional block copolymer rapidly elicits protective responses against multiple diverse ZIKV isolates. This represents potential for an easy-to-administer and simple to manufacture vaccine candidate against ZIKV and possibly other emerging threats to global health.