Host Cell Protein Assay
Host cell proteins (HCPs) are proteins produced or encoded by host organisms used to produce recombinant proteins and other therapeutic biologics. During the recombinant protein production, host cells also coproduce proteins related to the normal cell functions such as cell growth, proliferation, survival, gene transcription, protein synthesis, and etc. Other non-essential proteins may also be released to the cell culture as a result of cell death. In general, apart from the therapeutic protein of interest, all endogenous proteins co-expressed by the host cells are called host cell proteins.
During biologics production, HCPs are a major component of process-related impurities. Immunogenicity is the primary risk associated with HCPs. Almost all HCPs carry clinical safety risks as foreign proteins due to the potential to cause immune response in humans. In addition, some HCPs can act as adjuvants to enhance immune response to a drug product. Certain HCPs with proteolytic activity can also affect drug product efficacy and stability if not adequately inactivated or removed. The amount of residual HCPs is generally considered a critical quality attribute of drug product, due to their potential to affect product efficacy and safety. Therefore, regulatory agencies, such as FDA and EMA, require biopharmaceutical and biotechnology companies to monitor the removal of HCPs in drug product during the bioprocess.
HCPs Assay at Creative Animodel
The presence of residual HCPs is a potential safety risk in any biopharmaceutical product. With years of experience, our team of protein experts assists clients with the use of effective HCPs assays to determine both the concentration and the quantity of host cell proteins. The assays are used accurately to monitor changes in the product concentration and the removal of HCPs after purification.For a large amount (﹥0.1%) of residual HCPs present in drug substance, Creative Animodel provides size exclusion (SEC), ion exchange (IEX), high performance liquid chromatography (HPLC), mass spectrum (MS), isoelectric focusing capillary electrophoresis (iCE) and SDS-PAGE methods to detect the residues.For a small amount (﹤0.1%) of residual HCPs, immunoassays are available for our clients. Enzyme-linked immunosorbent assay (ELISA) is the industry gold standard for HCPs measurement due to its high sensitivity and high throughput.
Our ELISA workflow:
HCPs mixture injected into an animal will elicit an immune response, and the animals will generate anti-HCPs antibodies against these foreign proteins. Using these polyclonal antibodies, a multi-analyte ELISA can be developed. Capture antibodies recruit the HCPs from samples and immobilize them to a 96 (or greater)-well plate. Then, detection antibodies, conjugated directly with an enzyme or through a biotin-avidin magnification, bind to the captured HCPs. An enzyme, commonly horseradish peroxidase (HRP), can catalyze the substrate to generate a colorimetric, chemiluminescent, or fluorescent signal that correlates with the amount of HCPs in the test sample (Figure 1).
Figure 1. Principle of ELISA for HCPs detection.
Creative Animodel provides a comprehensive range of HCPs assays to evaluate the biosafety of biologics. We can offer complete reports about residual HCPs in your test samples in a high-efficiency manner. If you have any needs, please don’t hesitate to contact us.
1. Fengqiang, W.; et al. Host-Cell Protein Measurement and Control. BioPharm International. Volume 28, Issue 6, pg 32-38.