Why Do I Need to Know My HCP Antibody Coverage?

During biopharmaceutical development and manufacturing, host cell protein (HCP) impurities must be carefully identified and monitored to guarantee patient safety, drug efficacy and stability and to achieve FDA/MHRA/EMA approval for your biotherapeutic drug substance. Immunoassays such as enzyme-linked immunosorbent assays (ELISA) are the gold standard for HCP detection and measurement. However, to validate a HCP ELISA and ensure it is fit for its intended use, the polyclonal antibody mixture used in the assay must demonstrate broad reactivity against a wide range of potential HCPs that could potentially occur during the production process of the specific biological drug.

To do this, SpotMap 2D is used in combination with Two-dimensional gel electrophoresis (2D, 2-DE) and Western blotting to automate the process of analyzing anti-HCP coverage – the percentage of immunodetection that an antibody reagent offers for the total population of HCPs. It does this by comparing a 2D gel or blot image of proteins detected with an anti-HCP antibody (i.e., secondary image) against an image revealing all HCP antigen proteins (i.e., primary image).

HCP coverage analysis is used for:

  • Bioassay Development- Characterize host cell proteins (HCP) and anti-HCP antibodies via 2D gels and Western blots.
  • Bioprocess Improvement – Assess the purification of biologic production through comparison of multiple in-process 2D gels.
  • Analytical Development – Developing process-specific bioassays for use in HCP analysis of new biologics and biosimilars.
  • Development of analytical methods (choice and validation of immunoassay reagents)
  • Selection and validation of the most appropriate generic HCP ELISA kit
  • Bridging studies to support assay replacement (e.g. change from commercial assay to platform assay or process-specific assay)
  • Generic assay re-validation for every new batch of reagent
  • Process- and platform-specific assay revalidation after changes that could affect HCP composition
  • Optimization of bioprocesses

The U.S., European and Japanese Pharmacopoeia all specify the use of 2D gel electrophoresis followed by Western blot analysis (2D Western blotting) as the gold standard for orthogonal anti-HCP antibody characterization to evaluate anti-HCP antibody coverage:

HCP antibody coverage software