Degirmencay, Abdullah; (2024) Strategies to Improve TCR Expression and T cell Function. Doctoral thesis (Ph.D), UCL (University College London).

Preview

Text Abdullah Degirmencay PhD thesis final submission.pdf - Accepted Version Download (9MB) | Preview

Abstract

TCR gene therapy is one of the promising adoptive cellular therapies which relies on transferring antigen specific TCRs into autologous T cells obtained from patients. Increasing the introduced therapeutic TCR expression in T cells has a vital importance, as poor surface expression could cause sub-optimal avidity of the therapeutic TCR, thereby limiting the efficacy of the treatment. Therefore, developing strategies to augment the density of the introduced TCR remains a research focus in this field. In this thesis, I have employed two different strategies to enhance the introduced TCR expression and antigen specific function of human primary T cells. The first strategy was to determine novel TRBV framework residues whose substitutions could improve TCR expression. Analysis of TRBV regions of previously identified (by Stauss Lab) ‘weak’ and ‘dominant’ TCR libraries revealed 11 candidate residues to perform amino acid substitutions. The results indicated that a single amino acid change can double TCR expression. Further increases in TCR expression were observed with combining residue changes on both TCR chains. As few as three residue changes resulted in substantial enhancement of TCR expression levels and antigen specific function of the transduced T cells with increased cytokine production and boosted cytotoxicity. The second strategy was to determine whether TCR expression in human T cells is limited by CD3 chains, and whether this could be exploited in TCR gene therapy. Experiments with human T cells indicated that CD3 is a rate limiting factor in TCR expression as its overexpression enhanced endogenous TCR by 3-fold. As endogenous and introduced TCRs compete for the limited CD3 in human T cells, the supply of additional CD3 could alleviate this limitation and be used to improve antigen specific TCR expression. Experiments with 12 antigen specific TCRs demonstrated that additional CD3 can substantially increase the surface expression of the introduced TCRs in human T cells. Increased TCR density conferred human T cells with enhanced antigen specific IL-2 and IFN- productions and increased cytotoxicity in response to cognate antigen at low peptide concentrations.

Download activity - last month

Export as XMLCSVJSON

Download activity - last 12 months

Export as JSONCSVXML

Downloads by country - last 12 months

Export as XMLCSVJSON

Archive Staff Only

View Item