Interferon – Potency Assays

Impurities (HCP)

To detect Host Cell proteins (HCP) in biologicals, Texcell sets up custom ELISA assays for process-specific testing.

Steps included in project:

  • Characterization of the HCP
  • Production of polyclonal specific antibodies
  • Affinity purification & Biotinylation of specific antibodies
  • ELISA development and optimization
  • ELISA validation according to ICH Q2R1, EMA, FDA guidelines
  • GMP testing & lot release

Methods used are 2D Western Blot and ELISA.

Potency Assays

Texcell is developing or transferring custom bioassays:

  • In vivo: on small animals
  • In vitro: cell lines or primary cells

Various readout possibilities include:

  • Flow cytometry
  • Antibody response
  • Proliferation & Cytotoxicity using non-radioactive dyes
  • Soluble mediators in supernatants (eg cytokines by ELISA)
  • Absorbance, Fluorescence (FRET), Bioluminescence (BRET)
  • ElectroChemiLuminescence (ECL)/ MesoScale Discovery
  • ELISPOT (Zeiss reader)
  • Western Blot
  • Epifluorescence
  • RT-qPCR

Results are computed according to the parallel line method (US/European Pharmacopoeia).

Bioassays are used for various purposes, such as:

  • Proof of concept
  • Neutralizing potential of unwanted antibodies against biologicals (ADA);
  • Potency assays for batch release and stability testing

Standard assays are:

  • Antiviral activity using an infectivity assay for interferons
  • Streptokinase