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Title: Characterisation of CD3-enhanced gene-modified CD4+ T cells for cancer immunotherapy
Author: Piapi, Alice
ISNI:       0000 0004 7227 5556
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2017
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TCR gene transfer is used to redirect the antigen specificity of T lymphocytes towards known tumour antigens. TCR gene therapies in murine studies have shown promising results. However, in the clinic they have often generated sub-optimal responses, when compared to treatments with tumour infiltrating lymphocytes. Previous work to improve TCR gene therapy has demonstrated that transferring additional CD3 genes increases TCR expression of both endogenous and introduced TCR, in CD4+ and CD8+ T cells. In vivo experiments demonstrated that CD8+ T cells, transduced with TCR and additional CD3 were more effective in tumour protection than T cells transduced with the TCR alone. In this thesis the effects of CD3 (and as a consequence TCR) overexpression were studied in CD4+ and CD8+ T cells, that had been transduced with a retroviral vector containing the CD3 chains genes (CD3-GFP). In vitro analysis showed that CD4+ T cell expressed higher levels of TCR compared to CD8+ T cells, both before and after transduction with the CD3-GFP vector. This associated with higher Ca2+ and CD107a concentration, but no difference in T cell activation or proliferation. Unexpectedly, we found that increased TCR expression did not improve T cell functional avidity following polyclonal or peptide-specific stimulation. In vivo CD3-enhanced CD4+ T cells survived for longer and were recovered in higher percentages, compared to CD3-enhanced CD8+ T cells and mock transduced CD4+ T cells, both in non-competition and competition experiments. Interestingly, this was observed despite a down-regulation of TCR levels in the CD3-enhanced CD4+ T cells, compared to their pre-transfer TCR levels, which was not observed in the control-transduced CD4+ T cells. The mechanism that drives TCR down-regulation and its biological meaning are unknown and require further investigation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available