To generate HLA-restricted, TAA-binding TCRs (normally eliminated by central tolerance), Abdelfattah et al. (1) mutated a TAA peptide of interest by a single amino acid, (2) used the mutant peptide to expand and identify endogenous reactive T cells specific for the mutated peptide, (3) produced a massively mutagenized CDR3 region of the selected TCRs in Jurkat cells, and (4) identified TCRs that switched specificity back toward the target TAA. This process generated TCRs against the neuroblastoma TAA tyrosine hydroxylase (TH), which, when expressed in T cells, led to cytotoxicity and in vivo efficacy against TH+ tumors, without off-target promiscuity.
Contributed by Alex Najibi
ABSTRACT: Many promising targets for adoptive T cell therapy (ACT) are self-antigens, but self-reactive T cells are generally eliminated during thymic selection or diverted to regulatory phenotypes. To bypass T cell tolerance and obtain potent and safe T cell therapeutics, we developed T-Switch, an in vitro T cell receptor (TCR) engineering platform for the creation, modification, and comprehensive profiling of TCRs that can target self-antigens. T-Switch first expands T cells that recognize a "foreign" peptide closely related to a self-antigen. The fine specificity of the TCR is then modified by directed evolution of the peptide binding region to switch its specificity to the self-antigen of interest. We applied T-Switch to engineer synthetic TCRs reactive to a tumor-associated self-antigen, validated the safety and efficacy of this approach, and detected no off-target recognition as measured against the human proteome. Thus, T-Switch represents a resource for the creation of collections of highly sensitive synthetic TCRs for T cell-based immunotherapies.
Author Info: (1) Department of Genetics, Harvard Medical School, Division of Genetics, Brigham and Women's Hospital, Howard Hughes Medical Institute, 77 Avenue Louis Pasteur, Boston, MA 02115,
Author Info: (1) Department of Genetics, Harvard Medical School, Division of Genetics, Brigham and Women's Hospital, Howard Hughes Medical Institute, 77 Avenue Louis Pasteur, Boston, MA 02115, USA. (2) Department of Genetics, Harvard Medical School, Division of Genetics, Brigham and Women's Hospital, Howard Hughes Medical Institute, 77 Avenue Louis Pasteur, Boston, MA 02115, USA. (3) Department of Genetics, Harvard Medical School, Division of Genetics, Brigham and Women's Hospital, Howard Hughes Medical Institute, 77 Avenue Louis Pasteur, Boston, MA 02115, USA. Electronic address: selledge@genetics.med.harvard.edu.
