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The beta-gal interferon assay: a new, precise and sensitive method.

U Hammerling·E Bongcam-Rudloff·N Setterblad·R Kroon·A K Rehnström·E Viitanen·G Andersson·L Sjödin
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Abstract

Cells of a human glioblastoma line were stably transfected with a glial fibrillary acidic protein (GFAP) promoter sequence/lacZ reporter gene. Following this modification, they produced Escherichia coli beta-galactosidase constitutively in amounts that could be measured through their conversion of an added fluorophore into a product readily estimated by fluorimetry. Human interferons (IFN) selectively and in a dose-dependent manner reduce the formation of beta-galactosidase in this system. We have used it as the basis for a novel assay that is sensitive (4-40 pg/ml), precise, completed in 30 h, and applicable to both type I and type II human IFNs. Statistical analysis showed interassay relative standard deviations ranging from 5% to 11%, and most individual assays revealed potencies with limits of error within 85%-115%. Neither partially trypsin-digested IFN nor the other cytokines and mitogens we tested reacted in this system, except for tumor necrosis factor-alpha (TNF-alpha). The high selectivity was further shown by the loss of response to IFN in the presence of the appropriate specific anti-IFN or anti-IFN-gamma receptor antibodies.

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Biological AssayFluorometryGenes, ReporterHumansInterferonsPlasmidsReproducibility of ResultsSensitivity and SpecificityTumor Cells, Culturedbeta-GalactosidaseJournal Article

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U Hammerling, E Bongcam-Rudloff, N Setterblad, R Kroon, A K Rehnström, E Viitanen, G Andersson, L Sjödin. 1998. The beta-gal interferon assay: a new, precise and sensitive method.. https://doi.org/10.1089/jir.1998.18.451

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