Cell-Based: Bioactivity & Antiviral
Assays

• Widely accepted standard bioassay for determining the biological activity of interferons (IFNs)
• 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

Frequently used systems (high level of assay sensitivity and accuracy):

• Human A549/EMCV
• Bovine MDBK/VSV
• Mouse L929/VSV 

CPE assays are inherently complex due to the metabolic state of cells, virus replication, and the ability of IFN to protect cells. Our years of knowledge and expertise in CPE assays will reduce variability and provide you with reproducible quality results.

Results are provided either as a graphical representation of dye binding which allows slope and parallel line analysis, or visually determined from microscopic examination of the CPE and determination of the dilution of test samples which protects 50% of the cells. 

• Accurate determination of sample inhibitory effect on the biological activity of cytokines such as interferons (IFNs)
• Neutralizing activity measurement performed in a cell-based assay format using serum, plasma, cell culture media, or tissue culture media samples may be used as an anti-drug antibody (ADA) assay

The standard method of accurately determining whether a sample may inhibit the biological activity of cytokines is the neutralization assay. Results, provided either as a visual read or in a graphical format, reveal the ability of a sample to block the activity of IFN added at a specific concentration which provides 100% cell protection.

Suitable for serum, plasma, cell culture media, or tissue culture media samples. May be used as an anti-drug antibody (ADA) assay for certain therapeutics.

• Evaluate cytokine and other modulator activities with growth inhibition, growth promotion, and cytotoxicity assays
• Utilizes cell lines sensitive to IFNs or other growth-modulating cytokines
• Allows cell line screening to address specific client applications and clinical indications

Growth promotion and inhibition assays are often used to measure cytokine and drug activity profiles. Such Proliferation and Anti-Proliferation (AP) assays utilize a variety of cell lines and protein or small molecule stimuli to address specific applications and clinical indications. EC50 or IC50 results are provided.

Citation:

1. Bis, R.L. et al., (2014), "High yield soluble bacterial expression and streamlined purification of recombinant human interferon α-2a", Protein Expression and Purification, 99:138, DOI: 10.1016/j.pep.2014.04.010 (link)

Accurate measurement of a sample’s ability to induce cytokine production and/or release from cell lines or isolated donor cells is the standard assay for certain applications, such as measuring IL-18 activity. A key readout in many of these assays is interferon-gamma (IFN-γ), which is secreted by responsive cells when stimulated by cytokines such as IL-18, IL-12, and IL-15. Because IL-18 is made as an inactive precursor and must be processed to function, simply detecting the protein does not show whether it is active. Measuring IFN-γ release from stimulated cells provides a direct, functional readout of biological potency that standard immunoassays cannot deliver.