Among antibody-based drugs, immunoglobulin G (IgG) makes up most of the ones approved by the FDA. To find the best cell line for making one of these drugs, bioprocessors quantify the IgG produced. “During this manufacturing process, thousands of individual cell clones need to be screened—for example, using IgG quantification—to identify the clone best suited to manufacture the target drug of interest,” says Nigel Skinner, head of marketing at the Andrew Alliance SA, a Waters company. “This screening process requires accurate and reproducible tools and methods.”
In the biopharmaceutical industry, scientists quantify monoclonal antibodies (mAbs) in various ways, including Protein A HPLC, bio-layer interferometry, ELISA and immunoturbidimetric assays. Despite the variation among these tests, they all require sample preparation, such as centrifugation or dilution to remove whole cells, cellular debris, and contaminants, because the mAbs are in the cell-culture supernatants. Skinner describes these as “complex and heterogenous mixtures, that can interfere with these techniques and the accuracy of the output data.”
Conversely, Skinner points out that no sample preparation is required with Valitacell’s Valita®TITER and Valita®TITER Plus assays, which use fluorescence polarization (FP). By using FP to detect IgG, “the presence of cells in the test sample will not interfere with IgG quantification, even in supernatants containing 15 million cells per milliliter.”
An investigation conducted by Valitacell, Skinner says, showed that using Andrew Alliance’s Andrew+ Robot to prepare Valitacell assay plates increased the reproducibility over manual preparation. Skinner says that the key advantages are a “reduction in human error and an increase in the production of reproducible, reliable data.”
In many steps related to bioprocessing, adding automation improves reproducibility. There’s always a tradeoff in moving from manual to automation—the key tradeoff being if the improvements offset the price. With validation studies, bioprocessors can more accurately compare options.