Bio-Rad SPR Studies Demonstrate Rapid Screening and Characterization of Phage Display and Hybridoma Antibodies

Bio-Rad Laboratories, Inc., a multinational manufacturer and distributor of life science research and clinical diagnostics products, today announced the outcome of a new phage display study that augments the previously demonstrated utility of the ProteOn™ XPR36 protein interaction array system. Based on Surface Plasmon Resonance (SPR), the Proteon XPR36 system is capable of rapid screening of monoclonal antibody (mAb) supernatants.

The original study described in technical note (number 5540) demonstrates the rapid and precise screening and ranking of 20 hybridoma supernatants using the ProteOn XPR36 protein interaction array system. Using the ProteOn XPR36 system, five high-affinity monoclonal antibodies were identified, and four of these were selected for further purification and epitope mapping. Two of the antibodies recognize different epitopes on the IL-9 antigen. Both epitope mapping and hybridoma ranking were accomplished efficiently using the One-shot Kinetics™ approach and parallel processing capability of the ProteOn XPR36 system. This work can be easily enhanced to include kinetic constant determination of hundreds of supernatants within only a few hours.

In the more recent phage display study, Bio-Rad researchers demonstrated the efficient and rapid application of the ProteOn XPR36 system for screening antibody antigen-binding fragment (Fab) phage display libraries for the identification and characterization of therapeutic antibodies. The results were presented in a poster at the recent 2008 Society for Biomolecular Sciences conference in Dresden, Germany

Panning phage display libraries for potential Fab candidates, though extremely powerful, is both time consuming and costly. A multiplex SPR array system, such as the ProteOn XPR36 system, on the other hand, can provide rapid screening of Fab supernatants, without the need to purify or transfect.

The conventional Fab library screening workflow usually consists of four phases:

Fab panning

Assembly of the Fab and Fc fragments into an IgG 

Affinity maturation

Fc mutation analysis for modifying antibody-dependent cell-mediated and complement dependent cytotoxicity (ADCC and CDC).

The ProteOn XPR36 protein interaction array system replaces phases one and two and provides kinetic measurements that can distinguish low affinity antibodies from those with low expression levels — which ELISA assays cannot do. The Fab panning phase is replaced by rapid kinetic analysis of a large number of Fab supernatants to select those with high affinity for the antigen of interest. After a quick binding study that validates the high affinity candidates, 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.

Availability
Bio-Rad’s technical note (bulletin 5540) is available either from a local Bio-Rad sales office or can be downloaded via the company article page.