Recombinant swine beta interferon protects swine alveolar macrophages and MARC-145 cells from infection with Porcine reproductive and respiratory syndrome virus.
Swine beta interferon (swIFN-beta) produced in HEK 293 cells infected with a recombinant, replication-defective human adenovirus 5 (Ad5) encoding the swIFN-beta gene was tested for antiviral activity against Porcine reproductive and respiratory syndrome virus (PRRSV). MARC-145 cells were incubated overnight with dilutions of supernatant fluids from HEK 293 cells infected with Ad5-swIFN-beta or with an Ad5 control virus (Ad5-Blue). Treated cells were infected with PRRSV; MARC-145 cells incubated with Ad5-Blue supernatants developed cytopathic effects (CPE), whereas those incubated with swIFN-beta showed no CPE. To confirm the antiviral activity of swIFN-beta, culture fluids from Ad5-swIFN-beta-infected cells were affinity-purified on a Sepharose-anti-swIFN-beta matrix, and the resulting fractions exhibited antiviral activity upon infection with PRRSV. The antiviral effects were specific, as they were blocked by mAbs against swIFN-beta. Additional cultures of MARC-145 cells treated with swIFN-beta-containing supernatants or affinity-purified swIFN-beta were infected with PRRSV and tested by real-time RT-PCR for viral RNA in culture supernatants at various times post-inoculation. These experiments confirmed the protective effects of swIFN-beta. swIFN-beta was also tested for antiviral activity on porcine alveolar macrophages (PAMs) obtained by bronchoalveolar lavage from PRRSV-negative swine. PAMs were treated with dilutions of swIFN-beta or Ad5-Blue culture fluids, infected with PRRSV and tested for viral RNA by real-time RT-PCR. The viral load data showed a dose-dependent protection in swIFN-beta-treated PAMs, whereas no protection was evident from Ad5-Blue culture fluids. The data demonstrate that swIFN-beta protects both MARC-145 cells and PAMs from PRRSV infection.
Overend
C
C
Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, Storrs, CT, USA.
Mitchell
R
R
Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, Storrs, CT, USA.
He
D
D
College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
Rompato
G
G
Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, Storrs, CT, USA.
Grubman
M J
MJ
Plum Island Animal Disease Center, ARS, USDA, Greenport, NY, USA.
Garmendia
A E
AE
Department of Pathobiology and Veterinary Science, University of Connecticut, 61 North Eagleville Road, Storrs, CT, USA.
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000998:Antiviral Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D002846:Chromatography, Affinity; D003588:Cytopathogenic Effect, Viral / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005822:Genetic Vectors; D006801:Humans; D007370:Interferon Type I / Q000276:immunology / Q000494:pharmacology*; D016676:Macrophages, Alveolar / Q000502:physiology / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000187:drug effects* / Q000502:physiology; D012367:RNA, Viral / Q000096:biosynthesis; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D014779:Virus Replication / Q000187:drug effects
D000911:Antibodies, Monoclonal; D000998:Antiviral Agents; D007370:Interferon Type I; D012367:RNA, Viral; D011994:Recombinant Proteins