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Bioassay Testing Services
Through its laboratory facilities in Piscataway, NJ, PBL InterferonSource offers bioassay testing services. PBL's bioassays for interferons are cytopathic effect inhibition assays, also known as CPE and antiviral assays. In these assays, one unit is defined as the quantity of interferon required per milliliter to reduce the cytopathic effect of viral infection by 50%. The assay system, specifically the cell and virus types, varies depending on the species of interferon to be analyzed. For example, human interferon alpha bioactivity can be measured on either bovine MDBK cells, human H226 cells, or human A549 cells with vesicular stomatitis virus (VSV).
CLICK HERE to view description of the cells, viruses and standards used in our assays.
PBL also offers neutralization assay services, which measure an antibody's ability to neutralize the CPE activity of the cytokine. The cells and virus listed in the table are used to measure the neutralizing activity of the corresponding antibody. For example, the neutralizing activity of anti-human interferon alpha may be measured using MDBK cells, VSV and interferon alpha. In addition to Bioassay services, we also provide assay and novel reagent development services
For complete information on this service contact PBL at Bioassay Services.
PBL has worked with many laboratories and Contract Research Organizations to provide fast and accurate CPE results.
Sample Requirements
- 100 µl per sample is needed if activity is greater than 2,000 units per ml
- 1 ml is needed if activity is less than 2,000 units per ml
- A completed Viral Inhibition Assay Submission Form. The form can be obtained by writing Bioassay Services
*Results are normally provided 2 to 3 weeks after receipt of samples, although assay times may vary.
Bioassays
- Visual read option = $600 set-up fee per 20 samples (no change), $110 per sample charge ($10 increase)
- Visual read plus Graph Pad option = $975 set-up fee per 20 samples ($75 increase), $110 per sample charge ($10 increase)
Visual Read: Our standard antiviral assay service is based on a visual read of the protection of cells from cytopathic effect (CPE) due to viral challenge. Samples are titrated in 96 well plates and protection is determined in comparison to virus (no IFN) and cell (no virus) controls. After maturation of the viral CPE the live cells are fixed and stained with a Crystal Violet solution. The wells are then examined under a microscope to determine which dilution protects 50% of the cells from cytopathic effect. This dilution is calibrated to a standard interferon solution to obtain Units/ml of the sample.
Graph Pad Analysis: (Optional, additional charge applies) We now offer an additional analysis for customers who prefer graphic results. In this process the same plates that have been read by visual read are used. The Crystal Violet is solublized from the cells with methanol and the OD read on a plate reader at 562-570 nm. These OD values are then transformed to % protection by setting the cell control as 100% and the virus control as 0%. The data is then graphed and analyzed in Graphpad Prizm using a variable slope sigmoidal curve fitting function. This option offers a few advantages: It considers all the data points in determining the EC50 Examines the slope of different samples and provides a sliding scale for the EC50 value compared to the visual read. Provides actual raw OD values for your in-house analysis
This option offers a few advantages:
1. It considers all the data points in determining the EC50
2. Examines the slope of different samples and provides a sliding scale for the EC50 value compared to the visual read.
3. Provides actual raw OD values for your in-house analysis
All published prices are subject to change without notice.
In addition to Bioassay services, we also provide assay and novel reagent development services.
Write to us for more details.
CLICK HERE for our mailing address.