Cytopathic Effect Inhibition Assay Service

Service Features:

  • Widely accepted standard bioassay for determining the biological activity of interferons (IFNs)
  • High level of assay sensitivity and accuracy
  • More than 20 years of experience serving Pharmaceutical, Biotechnology, Contract Research and Academic scientists
  • Services available for measurement of IFN-Alpha, IFN-Beta, IFN-Omega, IFN-Gamma, and IFN-Lambda bioactivity in human samples, in a variety of other species, and in multiple matrices

Interferons (IFNs) are pleiotropic cytokines with antiviral, antiproliferative, and immunomodulatory activities. The biological activities of IFNs can be assessed by bioassay methods that quantify any of these characteristics. However, the standard IFN bioassay has been the protection of cells from cytopathic effect (CPE) of certain viruses, since this was the initial activity which defined these molecules.


In the IFN bioassay illustrated in Figure 1, IFN-beta was titrated in a cytopathic effect inhibition (CPE) assay on A549 human lung carcinoma cells with encephalomyocarditis virus (EMCV). In this antiviral assay, approximately 1 unit/ml of interferon is the quantity necessary to produce an inhibition of the cytopathic effect of 50% (EC50). The units of IFN activity were determined colorimetrically with respect to the international reference standard for human interferon.


For a brief introduction on Cytopathic Effect Inhibition Assay click here.


Representative IFN Antiviral Assay Graph

Service Citations:

  1. High yield soluble bacterial expression and streamlined purification of recombinant human interferon α-2a. Bis et al., 2014, Protein Expression and Purification, 11:138-146. (link)
  2. High-Yields and Extended Serum Half-Life of Human Interferon α2b Expressed in Tobacco cells as Arabinogalactan-Protein Fusions. Xu et al., 2007, Biotechnology and Bioengineering 97(5):997. (link)
  3. GlycoPEGylation of recombinant therapeutic proteins produced in Escherichia coli. DeFrees et al., 2006, Glybiology, 16(9):833. (link)
  4. Lipopolysaccharide-induced Expression of Interferon-β Mediates the Timing of Inducible Mitric-oxide Sunthase Induction in RAW 264.7 Macrophages. Jacob and Ignarro, 2001, J. Biol. Chem., 276(51):47950. (link)

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