TCR-like human antibodies expressed on human CTLs mediate antibody affinity-dependent cytolytic activity.
The permanent genetic programming via gene transfer of autologous T cells with cell surface receptors directed toward tumor-related Ags holds great promise for the development of more-specific tumor therapies. In this study we have explored the use of Abs directed to MHC-peptide complexes (or TCR-like Abs) to engraft CTLs with exquisite specificity for cancer cells. First, we affinity matured in vitro a previously selected TCR-like Ab, Fab-G8, which is highly specific for the peptide melanoma-associated Ag-A1 presented by the HLA-A1 molecule. A combination of L chain shuffling, H chain-targeted mutagenesis, and in vitro selection of phage display libraries yielded a Fab-G8 Ab derivative, Fab-Hyb3, with an 18-fold improved affinity yet identical peptide fine specificity. Fab-G8 and Fab-Hyb3 were expressed on primary human T lymphocytes as cell surface-anchored Fab, demonstrating that T cells expressing the high-affinity Fab-Hyb3 molecule eradicate tumor cells much more effectively. Furthermore, the gain in ligand-binding affinity resulted in a 2-log improvement in the detection of peptide/MHC complexes on melanoma-associated Ag-A1 peptide-loaded cells. In summary, an affinity-matured Ab specifically recognizing a cancer-related peptide/MHC complex was generated and used to improve the tumor cell killing capacity of human T cells. This strategy, based on engraftment of T cells with in vitro engineered Abs, is an attractive alternative to the laborious, and in many cases unsuccessful, generation of highly potent tumor-specific T lymphocytes.
Chames
Patrick
P
Department of Pathology, Maastricht University, Maastricht, The Netherlands.
Willemsen
Ralph A
RA
Rojas
Gertrudis
G
Dieckmann
Detlef
D
Rem
Louise
L
Schuler
Gerold
G
Bolhuis
Reinder L
RL
Hoogenboom
Hennie R
HR
D000915:Antibody Affinity / Q000235:genetics; D000918:Antibody Specificity; D017951:Antigen Presentation / Q000235:genetics; D000951:Antigens, Neoplasm; D003001:Cloning, Molecular; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D018390:Gene Targeting; D005822:Genetic Vectors / Q000138:chemical synthesis; D015788:HLA-A1 Antigen / Q000276:immunology; D006801:Humans; D016056:Immunodominant Epitopes / Q000276:immunology / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins / Q000276:immunology; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism*
D000951:Antigens, Neoplasm; D015788:HLA-A1 Antigen; D016056:Immunodominant Epitopes; D007140:Immunoglobulin Fab Fragments; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D011948:Receptors, Antigen, T-Cell; D016692:Receptors, Antigen, T-Cell, gamma-delta