title: Functional comparison of engineered T cells carrying a native TCR versus TCR-like antibody-based chimeric antigen receptors indicates affinity/avidity thresholds.
abstract: Adoptive transfer of Ag-specific T lymphocytes is an attractive form of immunotherapy for cancers. However, acquiring sufficient numbers of host-derived tumor-specific T lymphocytes by selection and expansion is challenging, as these cells may be rare or anergic. Using engineered T cells can overcome this difficulty. Such engineered cells can be generated using a chimeric Ag receptor based on common formats composed from Ag-recognition elements such as αβ-TCR genes with the desired specificity, or Ab variable domain fragments fused with T cell-signaling moieties. Combining these recognition elements are Abs that recognize peptide-MHC. Such TCR-like Abs mimic the fine specificity of TCRs and exhibit both the binding properties and kinetics of high-affinity Abs. In this study, we compared the functional properties of engineered T cells expressing a native low affinity αβ-TCR chains or high affinity TCR-like Ab-based CAR targeting the same specificity. We isolated high-affinity TCR-like Abs recognizing HLA-A2-WT1Db126 complexes and constructed CAR that was transduced into T cells. Comparative analysis revealed major differences in function and specificity of such CAR-T cells or native TCR toward the same antigenic complex. Whereas the native low-affinity αβ-TCR maintained potent cytotoxic activity and specificity, the high-affinity TCR-like Ab CAR exhibited reduced activity and loss of specificity. These results suggest an upper affinity threshold for TCR-based recognition to mediate effective functional outcomes of engineered T cells. The rational design of TCRs and TCR-based constructs may need to be optimized up to a given affinity threshold to achieve optimal T cell function.
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel;
authors.forename: Ravit
authors.initials: R
authors.lastname: Oren
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel;
authors.forename: Moran
authors.initials: M
authors.lastname: Hod-Marco
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel;
authors.forename: Maya
authors.initials: M
authors.lastname: Haus-Cohen
authors.affiliation: Department of Immunology, Institute of Immunity, Infection and Transplantation, Royal Free Hospital, University College London, London NW3 2PF, United Kingdom;
authors.forename: Sharyn
authors.initials: S
authors.lastname: Thomas
authors.affiliation: Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
authors.forename: Dan
authors.initials: D
authors.lastname: Blat
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel;
authors.forename: Nerri
authors.initials: N
authors.lastname: Duvshani
authors.affiliation: Applied Immune Technologies, Haifa 32000, Israel.
authors.forename: Galit
authors.initials: G
authors.lastname: Denkberg
authors.affiliation: Applied Immune Technologies, Haifa 32000, Israel.
authors.forename: Yael
authors.initials: Y
authors.lastname: Elbaz
authors.affiliation: Applied Immune Technologies, Haifa 32000, Israel.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Benchetrit
authors.affiliation: Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel; and.
authors.forename: Zelig
authors.initials: Z
authors.lastname: Eshhar
authors.affiliation: Department of Immunology, Institute of Immunity, Infection and Transplantation, Royal Free Hospital, University College London, London NW3 2PF, United Kingdom;
authors.forename: Hans
authors.initials: H
authors.lastname: Stauss
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel; reiter@tx.technion.ac.il.
authors.forename: Yoram
authors.initials: Y
authors.lastname: Reiter
mesh_terms: D000906:Antibodies / Q000276:immunology*; D000915:Antibody Affinity; D019496:Cancer Vaccines; D003602:Cytotoxicity, Immunologic; D005818:Genetic Engineering; D015789:HLA-A2 Antigen / Q000378:metabolism; D006801:Humans; D016219:Immunotherapy, Adoptive / Q000379:methods*; D019169:Jurkat Cells; D009369:Neoplasms / Q000276:immunology / Q000628:therapy*; D011485:Protein Binding; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D015398:Signal Transduction; D037182:T-Cell Antigen Receptor Specificity; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D000906:Antibodies; D019496:Cancer Vaccines; D015789:HLA-A2 Antigen; D016693:Receptors, Antigen, T-Cell, alpha-beta; D011993:Recombinant Fusion Proteins