Bio-Rad speeds up antibody screening
The new data demonstrates how Bio-Rad’s ProteOn analyser can be used to rapidly screen potential therapeutic antibodies and provide researchers with rich data earlier in the development process without the need to purify the crude supernatants.
The therapeutic antibody market is one of the fastest growing segments of the pharmaceutical industry, with antibody therapy sales totalling over $25bn (€17.9bn) in 2007.
Antibody therapy development is often an iterative process that involves a cycle of generating and then optimising antibodies in order to improve their clinical potential.
As such, rapid screening methods that can decrease the time between each development cycle will help decrease the overall time to market.
According to Dr Renee LeMaire-Adkins, marketing manager for Protein Interaction Technologies at Bio-Rad, the ProteOn XPR36 can speed up the entire antibody screening process.
The ProteOn XPR36 combines surface plasmon resonance (SPR) with a CCD detector and a high-throughput microfluidic system to allow the rapid and accurate collection of kinetic data about various protein interactions.
“The high throughput of the ProteOn system is a huge advantage when analysing potential antibody therapeutics,” said Dr LeMaire-Adkins.
“Generally, the approach is to screen the antibodies and then obtain richer kinetic data to validate and characterize the positive hits in the primary screen, however the ProteOn lets researchers generate richer data earlier in the process so they can make more informed decisions about whether the antibodies are suitable for the disease target of interest while running less experiments.”
Previous work by the company showed how 20 hybridoma supernatants could be rapidly screened and ranked against the cell signalling gene human interleukin 9 (IL-9).
Using the ProteOn system five high-affinity mAbs were identified, four of which were purified, their kinetic binding constants reanalysed and epitope mapping performed using Bio-Rad’s ‘One-shot Kinetics’ approach.
In the new phage display study, Bio-Rad’s researchers demonstrated how the ProteOn could be used for screening antigen binding fragment (Fab) phage display libraries to identify and characterise potential therapeutic antibodies.
According to the company, a typical Fab screening experiment will consist of a somewhat laborious four phase approach that includes: Fab (antigen-binding fragment) panning; assembly of Fab and Fc (fragments crystallisable region) fragments into an IgG (Immunoglobulin G) antibody; affinity maturation; and Fc mutation analysis for modifying antibody-dependant cell-mediated cytotoxicity (ADCC) and complement dependant cytotoxicity (CDC).
“When researchers study antibody libraries using phage display they will typically use multiple technologies such as ELISA [enzyme-linked immunoSorbent assay] and FACS [fluorescent-activated cell sorting] to go through two phases of the screening process,” said Dr LeMaire-Adkins.
“However the ProteOn replaces ELISA and FACS allowing scientists to use a single technology for the first two phases ,thus simplifying their approach and saving time.”
The Fab panning phase is replaced by a rapid kinetic analysis of a large number of Fab supernatants to select those with high affinity for the antigen of interest while also providing kinetic data that distinguishes low affinity antibodies from those with low expression levels - something that ELISA assays cannot do
A quick binding study is then used to validate the high affinity candidates, before phase two of the conventional workflow is replaced by a single binding study that simultaneously affirms the high affinity of the reassembled IgGs and determines their expression levels.
