Antigenic Epitopes Identification Of The Structural Protein And RFLP Analysis Of ORF5 Of Porcine Reproductive And Respiratory Syndrome Virus Isolates In China

The antigenic and genetic variability of porcine reproductive and respirators syndrome virus (PRRSV) isolates in China were studied by immunofluoresent monolayer assays (1FMA) and restriction fragment length polymorphism (RFLP) of reverse transcription (RT) and polymerases chain reaction (PCR) amplified-PRRSVORFS fragments among 8 Chinese isolates. The aim is to characterize the antigenic epitopes of PRRSV isolates from different parts of China with a panel of 11 monoclonal antibodies raised against American PRRS isolate ISU-P. It indicated that the Chinese isolates belong to North American group. Two pairs of different primers of ORF7 were used to identify the genotype of PRRSV isolates in China, and then compared with the reference isolates of North American and European serotype and modified live PRRSV vaccine.The results further proved that PRRSV prevalent in China belongs to B genetype. Combining the restriction enzyme digestion patterns obtained from Mini, Hindi and Sactt, we observed 2 distinct RFLP patterns. We are able to distinguish field Chinese isolates from the U.S. modified live strains, by comparing the RFLP patterns of the PCR-amplified genomic fragment of ORF5 gene. It provid theoretic basis for establishing the differenial mothod of PRRSV isolates.