A bioassay is an experimental test performed using live cell cultures or mixtures of cellular components (lysate), in which the potency of a biomolecule is tested based on its effect on a measurable parameter, such as the production of another biomolecule, inhibition or catalysis of a biochemical reaction or induction of an immune response. Measurement of the specific activity of an enzyme, or titre of an antibody is done using a bioassay.
In March 2008, BioProcess International reported on a survey to determine how, where and for what purposes cell-based bioassays were being used. The survey was given to delegates of two conferences, one in Europe (IBC European Biological Assays Conference 2006) and one in the United States (IBC Biological Assay Development and Validation Symposium 2007).
The results indicated that bioassays are largely used by companies doing early development and production of biopharmaceuticals. A very broad range of assays are in use, but predominant types include those that utilize antibodies (immunoassays) and cell-based functional assays (one in which any step of the measured reaction involves a functional biological response, not simply a binding reaction). Cell lines are used more frequently than primary cells and genetically modified cell lines are common.
Robinson, CJ, Little, LE, Wallny, HJ. Bioassay Survey 2006-2007: Cell-Based Bioassays in the Pharmaceutical Industry. BioProcess International, March 2008.