Primary Screening Of The Crucial Gene Of HP-PRRSV HuN4Corresponding To Its Pathogenicity

Porcine reproductive and respiratory syndrome （PRRS) is one of the worldwideinfectious diseases to pig industry which make serious damage.The pathogen （Porcinereproductive and respiratory syndrome virus,PRRSV)is maior classified into VR2332strainand LV strain,it was first identified in China in1995and belongs to VR2332.In2006,the highlypathogenic PRRS outbreaks in the our country and resulted in great economic loses.HP-HuN4strain is one of the representative pathogen.HuN4F112vaccine originates from the HuN4strain, such virus is cultured in the MARC-145cell line. Through this method, the aim of project is to take the attenuated F15,F23,and F30toget a further study on animal models. Then to valuate the lesion of lung and immune system ofanimals when they have been infected such attenuated strains via the clinical inspection andpathogenic dissection and virus load. It suggested that there is no typical pathogenic changeduring the infection of F23and F30strain. In comparison to the F23strain, The F30causes theslighter lesion than the primary virus. While the F23and F30are cultured in the primary cell（PAM) for10times, the F23-PAM10strain can infect the cells but reflect no clinical symptomduring the animal experimentation at the same level of valuation system. However, the F30-PAM10returns to be as infectious as the virulent strain F5. For a further study to explore themechanism of the virulent-related genes, comprehensive analysis of gene sequencing and animaltests on HuN4F5，HuN4F23，HuN4F30，HuN4F23-PAM10and HuN4F30-PAM10showthat the28th（A),421th（K),584th（D) of Nsp2gene and the122th（F)of ORF6may play thedominant role in its pathogenicity.