Research Of The M And N Protein Genes Of Porcine Reproductive And Respiratory Syndrome Vaccine

Porcine reproductive and respiratory syndrome modified live viruses were imported from the United State and the Netherland. The modified live viruses were recuperated in MARC—145 cell line. The modified live virus of the U. S PRRSV was cloned at the limiting dilution. Cytopathic effects were observed on the MARC —145 cell monolayers infected with the cloned strain (PRRSVMc) in 72h postinfection. By 36h postinfection, the virions could be observed in ultrathin section of MARC —145 cell infected with PRRSVMc by electron microscope. Intracellular viral particles tended to accumulate within the cytoplasmic vesicles and appeared as spherical enveloped particles of 50— 60 nm in diameter. The PRRSVMc was identified by ELISA? 80 sera samples from the pigs which were suspected to be infected by PRRSV were detected by ELISA with the pure PRRSVMc antigen, 34 of which were found to be PRRSV positive. The positive rate is 42. 5%. It was possible that the antigen was made by using PRRSVMc. The report laid a basis for further research of PRRS modified vaccine.