Assays for CHO and NSO Cell Lines
With approximately twelve years of experience of developing host cell protein (HCP) assays for detection of host cell derived proteins from GS cell lines, we are committed to the consistent assay development. Our Western blot HCP assay and the GS HCP ELISA assay package are now available for use with GS-NS0 and CHOK1 cell lines.
The kits for the HCP ELISA (GS-NS0 and CHOK1 cell lines) and Western Blot (CHO, GS-CHO, GS-NS0 cell lines) are available for use by customers at their own site. Each kit contains reagents for five assays together with detailed protocols.
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GS HCP Western Blot Assay Package
Anti-HCP Antiserum: a key specialist component of the HCP assays. Raised against a cell extract prepared in Lonza’s Development laboratories from a GS null (non-product expressing) cell line. The antiserum was specifically selected for use in a Western blot format that is used to detect and semi-quantify HCPs in recombinant products produced in GS-NS0 and CHOK1 cell lines.
Specific HCP Control: to ensure that the separation, electroblotting and probing procedures of the assay are acceptable.
Know-How: a detailed methodology on how to perform the HCP Western blot.
GS HCP ELISA Assay Package
Anti-HCP Coating Antiserum: purified coat antiserum prepared from the selected anti-HCP antiserum in the Western Blot Assay. The antiserum was specifically selected for use in the ELISA format that is used to detect and quantify HCPs in recombinant products produced in GS-NS0 and GS-CHO cell lines.
Anti-HCP Biotinylated Antiserum: this is prepared from the purified coat antiserum.
High and Low HCP Inter-assay Control: to ensure that ELISAs performed on different days give comparable results.
HCP Assay Standard: to produce a standard curve where the unknown sample HCP concentration can be extrapolated from the known relevant assay standard concentration.
Know-How: a detailed methodology on how to perform the HCP ELISA.
For current Lonza GMP customers, we evaluate generic assays to establish their suitability for testing the product cell line as well as the purified product. This evaluation is performed using the most suitable assay available to demonstrate the specificity and the accuracy of the HCP assays (Western blot is used to show the suitability of the antisera and ELISA).
We can also evaluate both formats of the HCP Assays as an additional service. The evaluation service is performed at our Slough, UK facility where the purified product, the cell line supernatant and the cell medium are evaluated for specificity and accuracy in the appropriate HCP Assays. By Western Blot Assay, we want to demonstrate that the major HCPs in the product cell line supernatant are detected by the anti-HCP antisera.
In addition, we assess the cross-reaction with the anti-HCP antisera used in the assay. The HCP ELISA is evaluated to determine the minimum dilution at which the product can be tested and so retain the lowest limit of detection in the assay. The HCPs derived from the product cell line supernatant are assayed at different dilutions in the HCP ELISA to demonstrate parallel results and thus provide evidence of the similarity of the HCPs in the assay standard with those in the product cell line.
After reporting the results of the evaluation to the customer, these generic HCP Assays are available for the customer for in-house use. These assays can be used to detect HCPs in final product and in-process samples, and are suitable for the optimization of purification processes.