Assessing the potential of hypochlorous acid-oxidised allogenic tumour cells as a source of antigen for dendritic cell-based immunotherapy of ovarian carcinoma.
Doctoral thesis, UCL (University College London).
Ovarian cancer commonly relapses after remission and activating tumour-specific T cells with dendritic cells loaded with tumour cells is a promising approach to target residual microscopic tumours. SK-OV-3 cells expressing HER- 2/neu and MUC1 ovarian antigens were killed and their immunogenicity enhanced by hypochlorous acid (HOCI) oxidation. Treatment with 60 \muM HOCI for 1 h induced necrosis in all the cells. Oxidised, but not live SK-OV-3 were engulfed by monocyte-derived DCs. Autologous T cells primed with DCs of HLA-A2+ healthy volunteers loaded with oxidised SK-OV-3 (HLA-A2-) recognised oxidised SK-OV-3 and HLA-A2-restricted epitopes of MUC1 and HER- 2/neu. Responses were absent with heat- or hydrochloric acid (HCI)-killed SK-OV-3, thus HOCI oxidation and not cell death/necrosis enhanced the immunogenicity of SK-OV-3. Oxidised SK-OV-3 primed T cells did not respond to oxidised melanoma, or vice versa. Next, cells of ovarian cancer patients in remission, whose tumours overexpressed MUC1 and/or HER-2/neu, were tested using the same model. DCs of HLA-A2+ and A2- patients pulsed with oxidised SK-OV-3 stimulated T cells specific for oxidised SK-OV-3, and HER-2/neu and MUC1 epitopes. Oxidised SK-OV-3 loaded DCs further matured with CD40 agonistic antibody or monophosphoryl lipid A, primed stronger CD4+ and CD8+ responses than immature DCs. T cells stimulated this way also recognised autologous tumour cells from ascites, demonstrating that SK-OV-3 shared significant antigenic repertoire with primary tumours. Finally, this DC-based vaccination was tested in vivo using the B16.F10 melanoma model. B16.F10 highly expressed tyrosinase-related protein (TRP)-2, and all the cells were necrotic after 1 h treatment with 60\muM HOCI. Mice immunised intravenously and not intraperitoneally or subcutaneously with bone-marrow derived DCs loaded with oxidised B16.F10, responded to TRP-2 and oxidised B16.F10. Oxidised and not heat- or HCI-killed B16.F10, primed specific T cells in vivo. DCs were required for efficient delivery for processing and presentation of oxidised B16.F10 in vivo.
|Title:||Assessing the potential of hypochlorous acid-oxidised allogenic tumour cells as a source of antigen for dendritic cell-based immunotherapy of ovarian carcinoma|
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