RNA pulsed Dendritic Cells as Immunotherapy for Melanoma

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Malignant melanoma remains a formidable challenge to patients, physicians, and scientists. Although surgical resection serves as the primary therapy and is often curative, melanoma recurs both locally and at distant sites. Unfortunately, current adjuvant therapies have not improved the dismal prognosis associated with regional and metastatic disease. This research focuses on the use of immunotherapy to treat micrometastatic and recurrent melanoma. Information gained through this preclinical research will be applied to developing an effective clinical melanoma vaccine. Immunologic rejection of tumor cells is mediated by cytotoxic T-lymphocytes (CTL) which recognize specific tumor- associated antigens (TAA). Antigen presenting cells, such as dendritic cells (DC), have been shown to generate an antigen-immunologic response both in vitro and in vivo after priming with TAA. Current research and clinical trials are underway at this institution loading of DC with tumor lysates and TAA peptides. This research project will attempt to optimize the CTL response against melanoma by methodologically studying the methods used to prime DC with tumor RNA induce unexpectedly potent tumor-specific CTL responses. Specifically, DC will be isolated through leukopheresis from patients with melanoma in whom tumor cell lines can be established. The DC from these patients will be primed with total tumor RNA from the patients' own tumor, or primed with combinations of previously isolated RNA for melanoma-specific TAA such as MART-1, MAGE-3, tumor, or primed with combinations of previously isolated RNA for melanoma-specific TAA such as MART-1, MAGE-3, tumor, or primed with combinations of previously isolated RNA for melanoma-specific TAA such as MART-1, MAGE-3, tyrosinase, and gp100. The primed dendritic cells will be incubated with CTL. These CTL will subsequently be mixed with melanoma cell lines and the percentage of lysed cells will be quantified using a chromium release assay. The antigen that yields the greatest cytoxicity will then by directly tested against the current method of pulsing dendritic cells with protein yields the greater cytotoxicity will then be directly tested against the current method of pulsing dendritic cells with protein lysates and peptides. Data gained from this preclinical work will guide future uses of vaccine development in the clinic.