Foldvari et al. developed a pipeline to map TCR reactivity to the complete proteome to evaluate TCR candidates for clinical translation. The in vitro pipeline first assessed TCR "fingerprints" of 1G4 (NY-ESO-1) and A23 (CD20) to search for potentially cross-reactive peptides in the human proteome, and validated physiologically relevant candidate cross-reactive peptides in silico and in cell lines. Mapping the alloreactivity profiles of 1G4 and A23 TCRs revealed cross-recognition of unintended HLA alleles within the HLA-A02 supertype. The A23 TCR rejected established tumors in an HLA-A2-transgenic mouse tumor model, persisted in treated animals, and showed no off-target reactivity.
Contributed by Shishir Pant
ABSTRACT: Cancer immunotherapy using T cell receptor-engineered T cells (TCR-Ts) represents a promising treatment option. However, technologies for pre-clinical safety assessment are incomplete or inaccessible to most laboratories. Here, TCR-T off-target reactivity was assessed in five steps: (1) Mapping target amino acids necessary for TCR-T recognition, followed by (2) a computational search for, and (3) reactivity screening against, candidate cross-reactive peptides in the human proteome. Natural processing and presentation of recognized peptides was evaluated using (4) short mRNAs, and (5) full-length proteins. TCR-Ts were screened for recognition of unintended HLA alleles, and as proxy for off-target reactivity in vivo, a syngeneic, HLA-A*02:01-transgenic mouse model was used. Validation demonstrated importance of studying recognition of full-length candidate off-targets, and that the clinically applied 1G4 TCR has a hitherto unknown reactivity to unintended HLA alleles, relevant for patient selection. This widely applicable strategy should facilitate evaluation of candidate therapeutic TCRs and inform clinical decision-making.
Author Info: (1) Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway. Precision Immunotherapy Alliance, University of Oslo, O
Author Info: (1) Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway. Precision Immunotherapy Alliance, University of Oslo, Oslo, Norway. (2) Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway. Precision Immunotherapy Alliance, University of Oslo, Oslo, Norway. (3) Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway. Precision Immunotherapy Alliance, University of Oslo, Oslo, Norway. (4) Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway. Precision Immunotherapy Alliance, University of Oslo, Oslo, Norway. (5) Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway. Precision Immunotherapy Alliance, University of Oslo, Oslo, Norway. (6) Precision Immunotherapy Alliance, University of Oslo, Oslo, Norway. Department of Immunology, University of Oslo and Oslo University Hospital, Oslo, Norway. (7) Precision Immunotherapy Alliance, University of Oslo, Oslo, Norway. Department of Immunology, University of Oslo and Oslo University Hospital, Oslo, Norway. (8) Department of Oncology, Oslo University Hospital Radiumhospitalet, Oslo, Norway. (9) Institute of Immunology, Charit - Universittsmedizin Berlin, Berlin, Germany. (10) Institute of Veterinary Pathology, Freie Universitt Berlin, Berlin, Germany. (11) Institute of Immunology, Charit - Universittsmedizin Berlin, Berlin, Germany. matthias.leisegang@charite.de. David and Etta Jonas Center for Cellular Therapy, The University of Chicago, Chicago, IL, USA. matthias.leisegang@charite.de. German Cancer Consortium (DKTK), partner site Berlin, and German Cancer Research Center (DKFZ), Heidelberg, Germany. matthias.leisegang@charite.de. (12) Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo, Norway. johanna.olweus@medisin.uio.no. Precision Immunotherapy Alliance, University of Oslo, Oslo, Norway. johanna.olweus@medisin.uio.no.
