Synthesis of empty african horse sickness virus particles

•Synthesized fully assembled, bilayered AHSV CLPs in vivo.•Synthesized partial and complete triple layered AHSV VLPs.•Rationally engineered and co-synthesized VP3 with a more hydrophilic mutant VP7.•Demonstrated increased CLP turnover due to increased soluble trimer concentration.•AHS VLP production requires further genetic manipulation and vector optimization.

As a means to develop African horse sickness (AHS) vaccines that are safe and DIVA compliant, we investigated the synthesis of empty African horse sickness virus (AHSV) particles. The emphasis of this study was on the assembly of the major viral core (VP3 and VP7) and outer capsid proteins (VP2 and VP5) into architecturally complex, heteromultimeric nanosized particles. The production of fully assembled core-like particles (CLPs) was accomplished in vivo by baculovirus-mediated co-synthesis of VP3 and VP7. The two different outer capsid proteins were capable of associating independently of each other with preformed cores to yield partial virus-like particles (VLPs). Complete VLPs were synthesized, albeit with a low yield. Crystalline formation of AHSV VP7 trimers is thought to impede high-level CLP production. Consequently, we engineered and co-synthesized VP3 with a more hydrophilic mutant VP7, resulting in an increase in the turnover of CLPs.