Celexion LLC

This report describes a new cell-surface display system, the Secretion and Capture Technology (SECANT™) platform, which relies on in vivo biotinylation of the protein of interest followed by its capture on the avidinated surface of the parent cell. Cell sorting techniques are then used to isolate clones that display target-binding protein. A distinguishing feature of this method is its ability to display complex proteins, such as full-length immunoglobulin G (IgG) antibodies, on living cells. In this proof-of-concept study, Saccharomyces cerevisiae cells that displayed Herceptin IgG were isolated from a 10,000-fold excess of cells that displayed a lysozyme-binding antibody.

The Secretion and Capture Technol. (SECANT⁾ platform utilizes a non-covalent cell surface attachment to display a protein of interest on the surface of yeast for protein engineering applications.With this method, diversified libraries of proteins including complex scaffolds (full-length IgG, Ig derivatives, multispecific antibodies, binding-scaffolds, etc.) can be constructed and screened for binding and non-binding attributes such as improved expression, stability, solubility, reduced aggregation, etc. via high-throughput flow cytometry or magnetic-bead sorting.We describe the novel aspects of the SECANT platform in conjunction with our fully-human, IgG₁ Library for de novo discovery of therapeutic antibodies.Addnl., we describe how the platform has been used to construct and screen a tandem scFv antibody library incorporating novel forms of diversity for improved binding to a target.We also demonstrate how the unique nature of the SECANT platform facilitates the purification and characterization of mutant clones directly from the selection output.