Porcine Reproductive and Respiratory Syndrome caused by Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) remains one of the important diseases in swine industry. A vaccine that is safe, effective and also elicit broad immune response against multiple antigens is desirable. In this study, we developed multi-cistronic DNA vaccines capable of co-expressing multiple structural proteins derived from PRRSV. To preserve the structure and function of each antigen protein, we employed self-cleaving 2A peptides to mediate separation of multiple proteins expressed by multi-cistronic genes. Six bi-cistronic genes encoding PRRSV GP5 and M proteins were generated, by which each construct contains different 2A sequ... More
Porcine Reproductive and Respiratory Syndrome caused by Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) remains one of the important diseases in swine industry. A vaccine that is safe, effective and also elicit broad immune response against multiple antigens is desirable. In this study, we developed multi-cistronic DNA vaccines capable of co-expressing multiple structural proteins derived from PRRSV. To preserve the structure and function of each antigen protein, we employed self-cleaving 2A peptides to mediate separation of multiple proteins expressed by multi-cistronic genes. Six bi-cistronic genes encoding PRRSV GP5 and M proteins were generated, by which each construct contains different 2A sequences derived from Foot-and-mouth disease virus (F2A), porcine teschovirus-1 (P2A) and Thosea asigna virus (T2A) either with or without furin cleavage site (Fu). Vectored by the mammalian expression plasmid pTH, all six bi-cistronic genes co-expressed the proteins GP5 and M at comparable level. Importantly, all six types of 2A sequences could mediate a complete self-cleavage of the GP5 and M. We next generated tri-cistronic DNA vaccines co-expressing the PRRSV proteins GP5, M and N. All homologous and heterologous combinations of P2A and F2A in tri-cistronic genes yielded a complete self-cleavage of the GP5, M and N proteins. Our study reports a success in co-expression of multiple PRRSV structural proteins in discrete form from a single vaccine and confirms feasibility of developing one single vaccine that provides broad immune responses against PRRSV.
