Exploring new approaches to T-cell therapy for Acute Myeloid Leukaemia

Caillaud, Marine 2024. Exploring new approaches to T-cell therapy for Acute Myeloid Leukaemia. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Background – Acute Myeloid Leukaemia is a very heterogenous and aggressive type of blood cancer affecting cells among the myeloid lineage with a five-year survival of 15%, therefore raising the need for new treatments. Growing interest in the anticancer powers of CD8+ T-cells has led to a focus on new immunotherapy strategies using conventional HLA-restricted CD8+ T-cells to specifically target AML malignancies without affecting healthy cells. This thesis aims at exploring new TCR-T approaches against AML. Results – In order to study HLA-A*02:01-restricted T-cells against AML cell lines from many different patients without the confounding problem of alloreactivity, I generated a panel of cancer cells knocked out for β-2-microglobulin and re-transduced these with a singlechain HLA-A*02:01 construct to produce AML cells expressing only HLA-A*02:01. In parallel, existing methods aiming at detecting cancer-specific T-cell responses did not enable the study and capture of viable T-cells. I therefore optimised an assay measuring CD107a and TNF markers at the surface of activated T-cells by flow cytometry, called T107 assay, to enable the recovery of viable cancer-reactive T-cells from clinical samples. My thesis mainly focused on a TCR-T approach against AML, thus requiring the discovery of a new TCR. Conjoint use of scHLA-A*02:01+ AML cancer cells with the T107 assay prior to cell sorting and TCR clonotyping enabled the isolation of a new HLA-A*02:01-restricted TCR (MC24.1) from clinical samples that conferred good recognition of primary AML blasts. In parallel, the multipronged TCR MEL8 isolated from metastatic melanoma patient MM909.24 was discovered by my laboratory team. CD8+ TCR-T-cells from three healthy donors expressing the MEL8 TCR were generated and observed to potently kill HLAA*02:01+ AML cells. Previous work with the MEL8 T-cell clone identified a super-agonist peptide ligand, MTSAIGILPV. This super-agonist ligand was capable of inducing Melan-Aspecific responses as well as killing of melanoma cancer cells in a greater proportion than natural peptide EAAGIGILTV. In a bid to induce enhanced AML-reactive T-cell responses, I used MEL8 super-agonist peptide MTSAIGILPV in a peptide priming approach from healthy donors and confirmed the superiority of the MTSAIGILPV peptide for this purpose in comparison to natural epitopes. Conclusions – Taken together, my results highlighted the potential of genetically modified cancer cells use alongside the T107 assay for the discovery of new cancer-specific TCRs. Additionally, multipronged AML-reactive T-cells were found to be induced in peptide priming approach using super-agonist peptide MTSAIGILPV. Finally, my studies have highlighted the great promises of MEL8 TCR in TCR-T approach against AML.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Medicine
Date of First Compliant Deposit:	1 July 2024
Last Modified:	01 Jul 2024 08:15
URI:	https://orca.cardiff.ac.uk/id/eprint/170169

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