Identification and Pre-Clinical Development of Tumour-Reactive T-cell Receptors from Tumour Infiltrating Lymphocytes

Abstract

The past decade has seen many advances in the field of cancer immunotherapy, with increased research efforts into optimising adoptive cell therapies. This has been particularly successful in the setting of metastatic melanoma, where both TIL and TCR T-cell therapies have had promising clinical trial results. However, researchers are yet to fully elucidate the reactivity profile of TIL products, and best identify and characterise the tumour-reactive portion of TIL. In the work for this PhD thesis, several different models were explored to best identify the tumour-reactive population within final melanoma TIL products. Through optimisation, a model was chosen where final TIL was co-cultured with autologous patient-derived tumour cell lines and CD137 was selected as a marker of tumour-reactivity to isolate and characterise the tumour-reactive TCRs. Through this approach, several TCRs were identified and a few were chosen for validation, which indicated they were HLA-A*0201-restricted, melanoma-reactive TCRs. In the second part of the project, pre-clinical validation of gp100-reactive TCRs isolated from a single patient TIL product was conducted in a series of flow-cytometry based assays. Through using different model systems to validate and compare the TCRs, an optimal candidate gp100 TCR was identified. This TCR was then directly compared to a control TCR originally isolated from a transgenic mouse model and previously used in gp100 TCR T-cell therapy in the clinic. Comparison with the TIL-derived gp100 TCR showed the two TCRs were comparable with regards to tumour-reactivity in the CD8+ T-cell population, however the TIL-derived TCR was considerably less cross-reactive than the control TCR. Collectively, the work in this PhD thesis demonstrates the safety benefit that TIL-derived TCRs can confer, while proposing an optimised model of identifying and pre-clinically validating tumour-reactive TCRs from TIL products.

Date of Award	1 Aug 2021
Original language	English
Awarding Institution	The University of Manchester
Supervisor	John Bridgeman (Supervisor) & Richard Edmondson (Supervisor)