Isolation And Indentification Of A Local Strain Of PRRSV And Research Of GP5Genic Vaccines

Porcine reproductive and respiratory syndrome (PRRS) is a contagious disease caused byporcine reproductive and respiratory syndrome virus (PRRSV). PRRS mainly causedreproductive disorder and porcine respiratory syndrome at variety of ages. The virus isclassified into2types, type I (European) and type II (North American) based on thegeneticand antigenic differences among the PRRSV strains. In1996, Guo Baoqing first isolated aPRRSV strain from aborted fetuses and verified the evidence of PRRSV in our country. At thepresent, PRRS has prevailed in the main worldwhile pig-raising country and districts andcaused pig-raising large economic losses in the world.This subject can be divided into three parts:1Isolation and sequence analysis of PRRSV SDDP strain.A strain of PRRSV was isolated and identified when the epidemic materials was detectedby RT-PCR from a pig farm in Shandong province, which named it SDDP. Complete genomeof SDDP was sequenced and cloned and analyzed by system evolutionary tree. The resultsrevealed that SDDP-PRRSV was the type of America PRRSV, and the homology of SX-1、JX143、JXA1(highly pathogenic PRRSV) was98.7%-99.7%. The nonstructural gene NSP2was largest variability. It lost90nucleotides (located in1540-1542,1594-1680ofNSP2)compared with VR2332.Structural gene ORF6and ORF7were relatively conservative.SDDP strain had a certain features compared with other domestic separation strains and laidthe foundation for the prevention and treatment of highly pathogenic PRRS. Lots of primerswere adjustment in the process of sequencing. The primers which were recommended in thisarticle were designed according to conservative sequence, and it provided a certain referencefor sequencing work.2Study on the different molecular adjuvant enhancing the effect of PRRSV GP5DNAvaccineGene vaccine is mainly composed of eukaryotic expression vector and protective antigen gene.Compared with the traditional vaccine, there was lots of advantage about gene vaccine,such as flexible design, high security, nature stability, low cost, and also induce humoralimmune and cellular immune, etc. However the nucleic acid vaccine also existed the problemof antibodies produce slowly and low level, effective adjuvants were added to overcome theseshortcomings, The method of improving the effect of gene immune was been explored byscholars at home and abroad, which in a gene expression vector introduced in immuneadjusting molecules is one of the important one of the measures.We select the complement C3d, test induced protein interferon10(IP-10), methodsurname bag three peptide (BS, pentapeptides (TP) as a molecular adjuvants and protectiveantigen PRRSV GP5construct to express pcDNA3.1carrier, restructured plasmid was largelyextracted and transfect293T cells, restructuring plasmid were intracellular expression by theindirect immunofluorescence. Restructured plasmid immune mice, the level of antibody, IL-4and IFN-γ in mice were tested through the ELISA kit.The results showed that antibody titer,IL-4and IFN-γ content were higher than the control group, group of pcDNA3.1group-IP-10-GP5was the best effect in molecular adjuvants, It was significantly differencescompared with blank control and pcDNA3.1-GP5group(P <0.05). It proved that the plasmidcan stimulate the body to produce higher level of humoral immune and cellular immune,IP-10molecular adjuvants can significantly boost the immune effect of PRRSV GP5genes.