[ Objective] To clone the porcine interleukin-18（/L-18） cDNA and explore the immunological effectiveness of porcine IL-18 as an adjuvant of genetic vaccine. [ Method] The spleen lymphccytes were isolated from Henan three-way cross-breeding pigs. According to the porcine IL-18 gene in GenBank, a pair of specific primers was designed. The full length cDNA of porcine IL-18 was amplified by RT-PCR. Subsequently, porcine IL-18 cDNA was cloned into pGEM-T vector and sequenced and analyzed. [ Result] The porcine IL-18 gene demonstrated an open reading frame of 579 bp encoding an inactive precursor protein with 192 amino acids. The precursor protein had no typical hydrophobic signal peptide and cleaved by interleukin-1 beta （IL-1β） converting enzyme（ICE） in caspase-1 splice site; the porcine mature protein had biological activity： After comparing with other porcine IL-18 genes, the nucleotide sequence homology was over 96% and the deduced amino acid homology was more than 98%. [ Conclusion] A full length procine IL-18 gene was gained. It lays the foundation for porcine IL-18 as an adjuvant of genetic vaccine.
[ Objective] The aim of this study was to investigate the construction and identification of siRNA expression vector targeting nucleocapsid protein N gone of PRRSV. [Method] Three siRNA oligonucleotides targeting nucleocapsid protein N gone sequence of PRRSV were designed or synthesized, and then inserted into CMV promoter downstream to clone into pSilencer 4,1 -CMV eukaryotic expression vector. The recombinant expression vector was identified by enzyme digestion and DNA sequencing. [ Result] The results showed that the siRNA interference recombinant plasmid vector pSilencer-N targeting nucleocapsid protein gone expression had been successfully constructed. [ Conclusion] This study lays a foundation for studies on the controlling PRRSV by RNA interference technique .
