title: Affinity maturation of T-cell receptor-like antibodies for Wilms tumor 1 peptide greatly enhances therapeutic potential.
abstract: WT1126 (RMFPNAPYL) is a human leukocyte antigen-A2 (HLA-A2)-restricted peptide derived from Wilms tumor protein 1 (WT1), which is widely expressed in a broad spectrum of leukemias, lymphomas and solid tumors. A novel T-cell-receptor (TCR)-like single-chain variable fragment (scFv) antibody specific for the T-cell epitope consisting of the WT1/HLA-A2 complex was isolated from a human scFv phage library. This scFv was affinity-matured by mutagenesis combined with yeast display and structurally analyzed using a homology model. This monovalent scFv showed a 100-fold affinity improvement (dissociation constant (KD)=3 nm) and exquisite specificity towards its targeted epitope or HLA-A2(+)/WT1(+) tumor cells. Bivalent scFv-huIgG1-Fc fusion protein demonstrated an even higher avidity (KD=2 pm) binding to the T-cell epitope and to tumor targets and was capable of mediating antibody-dependent cell-mediated cytotoxicity or tumor lysis by chimeric antigen receptor-expressing human T- or NK-92-MI-transfected cells. This antibody demonstrated specific and potent cytotoxicity in vivo towards WT1-positive leukemia xenograft that was HLA-A2 restricted. In summary, T-cell epitopes can provide novel targets for antibody-based therapeutics. By combining phage and yeast displays and scFv-Fc fusion platforms, a strategy for developing high-affinity TCR-like antibodies could be rapidly explored for potential clinical development.
authors.affiliation: Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: M
authors.identifier: http://orcid.org/0000-0002-7305-0012
authors.initials: M
authors.lastname: Ahmed
authors.affiliation: Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: D V
authors.initials: DV
authors.lastname: Tassev
authors.affiliation: Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.|Pediatric Stem Cell Transplant Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: A
authors.initials: A
authors.lastname: Hasan
authors.affiliation: Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.|Pediatric Stem Cell Transplant Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: T-Y
authors.initials: TY
authors.lastname: Kuo
authors.affiliation: Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: H-F
authors.initials: HF
authors.lastname: Guo
authors.affiliation: Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.|Pediatric Stem Cell Transplant Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: O'Reilly
authors.affiliation: Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: N-K V
authors.initials: NK
authors.lastname: Cheung
mesh_terms: D000818:Animals; D000915:Antibody Affinity; D045744:Cell Line, Tumor; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen / Q000276:immunology; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D007938:Leukemia / Q000628:therapy*; D008297:Male; D051379:Mice; D010446:Peptide Fragments / Q000276:immunology*; D019151:Peptide Library; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D057127:Single-Chain Antibodies / Q000627:therapeutic use*; D025721:WT1 Proteins / Q000276:immunology*
chemical_list: D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D010446:Peptide Fragments; D019151:Peptide Library; D011948:Receptors, Antigen, T-Cell; D057127:Single-Chain Antibodies; D025721:WT1 Proteins