Automated panning and screening of antibodies from phage display libraries

Antibody phage display technology is well established and widely used for selecting specific antibodies against desired targets. Using conventional manual methods, it is laborious to perform multiple selections with different antigens simultaneously. Furthermore, manual screening of the positive clones requires much effort. We have developed and optimized automated procedures of these processes using a magnetic bead processor for the selection and a robotic station for the screening step. Both steps are performed in a 96-well plate format. For screening, an enzyme-linked immunosorbent assay protocol suitable for a robotic station was developed. This system was first set up with protein and hapten molecules as model antigens to select antibodies from the VTT naive human single-chain antibody (scFv) library. Previously these antigens have been used successfully to select antibodies manually from the same library. The naïve library is modest in size (108), but yet panels of antigen specific antibody clones distinct by the amino acid sequences were achieved with this automated method. The selection and screening procedures were further developed and optimized for isolation of hapten specific antibodies recognizing solely the hapten conjugate and not the carrier protein. A multiplexed selection and screening was performed simultaneously for 12 hapten antigens differing by physical and chemical properties and size. The conjugation degree of each hapten to their carrier protein was validated by an MS analysis before the selection. Recombinant antibody fragments were successfully isolated against 8 of the 12 target antigens. All positive clones were produced efficiently in E. coli bacteria. The characterization of the binding properties of the best antibody clones for each hapten is in progress. In conclusion, the developed automated selection and screening method allows the efficient selection of antigen specific antibodies for multiple targets in parallel. It is also a powerful tool to screen concurrently various selection conditions for one antigen.