Prokaryotic expression of porcine type III interferon and studying on its antiviral activity

Abstract

Normally, type III interferon (IFN-lambda) was highly expressed in intestinal mucosa and other mucosal systems, with relatively stronger broad-spectrum antiviral ability and immune regulating ability Porcine epidemic diarrhea virus (PEDV) and porcine deltacorona virus (PDCoV) were two major intestinal pathogens causing diarrhea in piglets, which hindered the swine industry severely In this study, the recombinant plasmid containing PoIFN-lambda3 fragment was constructed The recombinant plasmid was then transformed into E coli Rosaetta cells for recombinant expression Analyzed by SDS-PAGE and western blotting, the results showed that the recombinant PoIFN-lambda3 (27 ku) was successfully expressed in the inclusion bodies of E coli cells After denaturation, purification and renaturation, the active PoIFN-lambda3 recombinant protein was obtained and was used to treat IPEC-J2 cells Challenged by recombinant PoIFN-lambda3, the immune-stimulating genes (ISGs), such as ISG15-, OAS1, Mx-1, IFIT1, IFITM1 and IFITM3 were all up-regulated significantly and reached to the peak (P 0 001) at 12 h post challenge For PEDV and PDCoV infection in IPEC-J2, the virus replication was detected after pretreatment, simultaneous treatment and post-infection treatment of recombinant PoIFN-lambda3 Compared with the control, the viral copy numbers of both PEDV and PDCoV were decreased significantly (P 0 05) after treatment of recombinant PoIFN-lambda3 The above results indicated that the purified and renatured PoIFN-lambda3 recombinant protein could have good biological activity The recombinant PoIFN-lambda3 can induce high expression of different ISGs in IPEC-J2, and can also inhibit PEDV and PDCoV replication in the host cells In summary, our study provided a basis for preventing and treating viral diarrhea in piglets