Recent studies have suggested an increasingly important and therapeutically relevant role for CD4+ T cells as direct effectors in immunotherapy. It has also become clear that antigens can access the MHC-II pathway via non-classical endogenous routes such as autophagy. The aims of this project were to investigate endogenous MHC-II processing of tumour antigens and explore methods that, by enhancing such processing, could increase T cell recognition of tumour cells. The frequency and diversity of T cell responses to the tumour antigen WT1 in healthy individuals and cancer patients was investigated. T cell responses were rare and only one epitope-specificity was identified in these donors. The Epstein Barr Virus Nuclear Antigen 1 (EBNA1), a protein that becomes more efficiently processed by autophagy when relocalised from the nucleus into the cytoplasm, was also investigated. When EBNA1-positive cells were treated with the CDK inhibitor Roscovitine, previously reported to relocalise EBNA1 into the cytoplasm, presentation of an autophagy-dependent indicator epitope was decreased. Roscovitine did not affect autophagy activity but decreased cellular levels of several autophagy adaptor proteins. siRNA Knock down of each autophagy adaptor showed CALCOCO2, NBR1 and OPTN were involved in the generation of an autophagy-dependent epitope from EBNA1; a control epitope was unaffected. Finally, efforts were made to define fundamental rules determining why only a subset of potential MHC-II epitopes are generated from an antigen by autophagy. Resistance to degradation by lysosomal peptidases was shown to be an important factor determining whether an MHC-II epitope can be generated by autophagy.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:600369 |
| Date | January 2014 |
| Creators | Williams, Luke |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/5000/ |
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