title: Directed evolution of an anti-carcinoembryonic antigen scFv with a 4-day monovalent dissociation half-time at 37 degrees C.
abstract: An scFv has been engineered to bind carcinoembryonic antigen (CEA) with a dissociation half-time >4 days at 37 degrees C. Two mutations responsible for this affinity increase were isolated by screening yeast surface-displayed mutant libraries by flow cytometry. Soluble expression of the mutant scFv in a yeast secretion system was increased 100-fold by screening mutant libraries for improved yeast surface display level. This scFv will be useful as a limiting case for evaluating the significance of affinity in tumor targeting to non-internalizing antigens.
authors.affiliation: Department of Chemical Engineering and Biological Engineering Division, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Christilyn P
authors.initials: CP
authors.lastname: Graff
authors.forename: Kerry
authors.initials: K
authors.lastname: Chester
authors.forename: Richard
authors.initials: R
authors.lastname: Begent
authors.forename: K Dane
authors.initials: KD
authors.lastname: Wittrup
mesh_terms: D002272:Carcinoembryonic Antigen / Q000276:immunology*; D019020:Directed Molecular Evolution; D006358:Hot Temperature; D007128:Immunoglobulin Fragments / Q000235:genetics* / Q000276:immunology; D010957:Plasmids
chemical_list: D002272:Carcinoembryonic Antigen; D007128:Immunoglobulin Fragments