Enterovirus(EV71) can cause severe neurological diseases,but the underlying pathogenesis remains unclear.The capsid protein,viral protein 1(VP1),plays a critical role in the pathogenicity of EV71.High level expression and secretion of VP 1 protein are necessary for structure,function and immunogenicity in its natural conformation.In our previous studies,5 codon-optimized VP1 DNA vaccines,including wt-VP1,tPA-VP1,VP1-d,VPl-hFc and VP1-mFc,were constructed and analyzed.They expressed VP1 protein,but the levels of secretion and immunogenicity of these VP1 constructs were significantly different(P<0.05).In this study,we further investigated the protein levels of these constructs and determined that all of these constructs expressed VPl protein.The secretion level was increased by including a tPA leader sequence,which was further increased by fusing human IgG Fc(hFc) to VP1.VP1-hFc demonstrated the most potent immunogenicity in mice.Furthermore,hFc domain could be used to purify VP1-hFc protein for additional studies.
