REAL-Select: Full-Length Antibody Display and Library Screening by Surface Capture on Yeast Cells

Rhiel L, et al., 9(12):e114887, PLoS One, 2014

This report describes a novel technology called REAL-Select (Reversible Expression of Antibody Libraries for Selection) for displaying full-length IgG-molecules or libraries for screening and clone characterization. This methodology does not require genetically encoded anchor proteins or intracellular antibody modifications. The cell wall anchoring of secreted antibodies is achieved by chemical coupling of Fc-binding ZZ domains (an artificial variant of protein A-derived B-domain with a high affinity to the Fc-region of IgG) that allow capturing of secreted antibodies onto the yeast cell surface. The affinity-matured antibodies obtained from REAL-Select retain their native form while allowing the detection of subtle changes in affinity by flow cytometry. An Octet RED system allowed the determination of binding kinetics of IgG analogs (subcloned and purified) with a high affinity and specificity to cMet protein. IgG analogs were captured onto anti-human-FC (AHC) biosensors. This methodology does not rely on the genetic background of the antibody-expressing host. Therefore, it is expected to be compatible with other eukaryotic expression hosts such as the mammalian cells and P. pastoris.

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