Synthesis of IFN-beta by virus-infected chicken embryo cells demonstrated with specific antisera and a new bioassay.
Transcripts of interferon-alpha (IFN-alpha) and IFN-beta genes are present in virus-infected chicken cells, but because of a lack of appropriate assays and reagents, it was unclear if biologically active IFN-beta is secreted. We have established a nonviral bioassay for the sensitive detection of chicken IFN (ChIFN). This assay is based on a quail cell line that carries a luciferase gene that is controlled by the IFN-responsive chicken Mx promoter. Luciferase activity was strongly stimulated when the indicator cells were incubated with ChIFN-alpha, ChIFN-beta, or ChIFN-gamma but not with chicken interleukin-1beta (ChIL-1beta). Unlike the classic antiviral assay that preferentially detects ChIFN-alpha, the Mx-luciferase assay detected ChIFN-alpha and ChIFN-beta with similar sensitivity. With the help of this novel assay and with rabbit antisera specific for either IFN-alpha or IFN-beta, we analyzed the composition of IFN in supernatants of virus-infected chicken embryo cells. Virtually all IFN produced in response to Newcastle disease virus (NDV) was IFN-alpha. However, IFN produced in response to influenza A or vaccinia virus (VV) was a mixture of usually more than 80% IFN-alpha and up to 20% IFN-beta. Thus, IFN-alpha and IFN-beta both contribute to the cytokine activity in supernatants of virus-infected chicken cells. Furthermore, the infecting virus appears to determine the IFN subtype composition.
Schwarz
Heike
H
Department of Virology, University of Freiburg, D-79104 Freiburg, Germany.
Harlin
Olof
O
Ohnemus
Annette
A
Kaspers
Bernd
B
Staeheli
Peter
P
D000818:Animals; D000918:Antibody Specificity; D001681:Biological Assay / Q000379:methods*; D002460:Cell Line; D002642:Chick Embryo / Q000276:immunology* / Q000821:virology*; D019204:GTP-Binding Proteins / Q000235:genetics; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D009980:Influenza A virus / Q000472:pathogenicity; D007375:Interleukin-1 / Q000032:analysis* / Q000096:biosynthesis* / Q000276:immunology; D008156:Luciferases / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D064547:Myxovirus Resistance Proteins; D009522:Newcastle disease virus / Q000472:pathogenicity; D009976:Orthomyxoviridae Infections / Q000276:immunology; D011401:Promoter Regions, Genetic; D011784:Quail; D014616:Vaccinia virus / Q000472:pathogenicity
D007106:Immune Sera; D007375:Interleukin-1; D064547:Myxovirus Resistance Proteins; D008156:Luciferases; D019204:GTP-Binding Proteins