• Korean Journal of Veterinary Service
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• v.22 no.4
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• pp.363-370
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• 1999

Isolation of PRRSV was attempted from 646 swine sera collected from swine farms. The MARC-145 cell, which is highly permissive to PRRSV, was used for virus isolation, propagation, IFA test, and VN test. Total 36 cytopathic viruses to MARC-145 cells were isolated. The virus isolates were identified as a PRRSV by the IFA test and VN test using the reference sera prepared by experimental infection of reference PRRSV CNV-1 into 30 day-old pig. In addition to serological conformation, ORF5 of genomic RNA of 6 selected cytopathic viruses were amplified by the RT-PCR. The resulting PCR products were examined by electrophoresis in 1.2% agarose gel. An appropriate bands of about 680bp including the flanking sequence of total 80bp were seen on agarose gel.

• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1076-1083
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• 2013

Seventeen compounds derived from traditional Chinese medicines (TCMs) were tested for their antiviral activity against porcine reproductive and respiratory syndrome virus (PRRSV) in vitro. Visualization with the cytopathologic effect (CPE) assay and the 3-(4, 5-dimethyithiazol-2-yl)-2,5-diphenyltetrazolium bromide test were used to determine the 50% cytotoxic concentration ($CC_{50}$) and 50% effective concentration ($EC_{50}$) in cultured Marc-145 cells. Among the tested compounds, chlorogenic acid and scutellarin showed potential anti-PRRSV activity. The $EC_{50}$ values were $270.8{\pm}14.6{\mu}g/ml$ and $28.21{\pm}26.0{\mu}g/ml$ and the selectivity indexes were >5.54 and 35.5, respectively. The time-of-addition and virucidal assay indicated that the anti-PRRSV activity of the two compounds could be due to their inhibiting the early stage of virus replication and/or inactivating the virus directly. The inhibition of the virus attachment was not observed in the adsorption inhibition assay. The inhibition ratios of chlorogenic acid and scutellarin were, respectively, 90.8% and 61.1% at the maximum non-cytotoxic concentrations. The results have provided a basis for further exploration of their antiviral properties and mechanisms in vivo. We believe that the chlorogenic acid and scutellarin have a great potential to be developed as new anti-PRRSV drugs for clinical application.