Establishment And Application Of An Indirect ELISA Of Porcine Reproductive And Respiratory Syndrome Virus N Protein

Porcine reproductive and respiratory syndrome(PRRS)is an economically important swine disease in the global swine industry.In 1987,the first PRRS characterized by reproductive failure,respiratory diseases and high mortality occurred in the United States,and the global pig breeding industry had a very significant impact.At the end of 1995,PRRS broke out in China and spread rapidly throughout the country,posing a more serious threat to China ’s pig industry.There are eight structural proteins in the gene structure of porcine reproductive and respiratory syndrome virus(PRRSV),of which open reading frame 7(ORF7)encodes the nucleocapsid N protein.N protein is the dominant structural protein in PRRSV,which is relatively stable.Animals infected with PRRSV will produce specific antibodies against N protein at the earliest time.The N protein sequence of PRRSV is the most different from that of other arteritis viruses.In this experiment,the expression,purification,and renaturation conditions of PRRSV N protein were optimized,and an indirect ELISA method for detecting PRRSV N protein antibody was established and the experimental conditions were optimized.The established indirect ELISA method showed that the S/P value ≥ 0.30 was positive and < 0.30 was negative.This method only reacted with PRRSV positive serum.The intra-batch and interbatch repeatability were less than 10%,and the sensitivity and specificity were respectively90.6% and 88.1%.The method has good sensitivity,specificity and repeatability.To accurately detect pigs without PRRS infection and take corresponding measures to prevent the spread of PRRS,effective PRRSV detection methods are of great significance for pig health detection and pig farm prevention and control.