Dendritic cells are efficient antigen-presenting-cells that can be used in tumour-antigen specific vaccination for malignant disease. Melanoma patients were recently treated with a dendritic cell vaccine expressing gp100 and Melan-A antigens after non-viral (CL22 peptide) transfection. Although clinical and immunological responses were noted, there was no correlation between responses and whole antigen expression levels in the vaccine cells that varied widely. Here, it is established that patient cells expressed detectable levels of Class I restricted epitopes from both antigens, although there was no correlation with whole antigen detection. CL22 transfected dendritic cells could simultaneously present a viral antigen (EBNA1) to CD8 and CD4 T-cells, which had not previously been demonstrated. Using RNA transfection, it was demonstrated that early after transfection cells are whole Melan-A positive yet negative for Class I epitopes and with time Melan-A antigen levels fall whilst Class I epitopes are generated. Loss of whole antigen expression seemed related to lysosomal function and, unlike the viral antigen EBNA1, Class I presentation from Melan-A was lysosome-dependent. For Class II presentation of EBNA1, cellular localisation seems to determine access to the Class II pathway although this depends on the time-scale over which epitope presentation is assessed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:556944 |
| Date | January 2012 |
| Creators | Rao, Ankit Rohit |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/3622/ |
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