VLP vaccines against HPV-induced tumors

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Human papillomaviruses (HPV are a necessary cause for cervical carcinoma, the third most common cancer among women worldwide. HPV DNA is detected in virtually every cervical carcinoma and about 50-60% of these are accounted for by the high risk HPV type 16. Efficient HPV replication conditions have not yet been mimicked in vitro thereby hampering the development of classical vaccines. However, when the major virion protein of the virus (L1) is over- expressed in eukaryotic cells, it self-assembles into virus-like particles (VLP). HPV VLP have become the leading strategy in vaccine trials for prevention of future HPV lesions by inducing neutralizing antibodies, but they are unlikely to have effects in the millions of women that are already infected and will not have any effect on existing cervical cancers that do no longer expression the L1 genes. They do, however, express the early gene products E6 and E7 that are selectively retained and expressed in cervical carcinoma and necessary for the transformed state of the cells. Therefore, incorporation of the E6 and E7 protein into chimeric VLP (cVLP) could confer a therapeutic potential to a VLP based vaccine. The tremendous potential of VLP has been shown in inducing T cell responses, in activating DC, in tumor preventive setting and, in preliminary ways also in tumor therapeutic settings and gene delivery. Based on these studies we now propose to explore the following new aims: 1) optimizing the use of HPV VLP as an antigen delivery system, 2) the use of HPV VLP as a tool for mapping human endogenously presented antigenic epitopes of HPV16 E6/E7 proteins, 3) the use of HPV VLP to explore the interaction of HPV with Langerhans cells, and 4) the use of HPV VLP as a gene delivery system. To achieve these aims the following methodology will be used: 1) delivery the of the HPV16 E6/E7 protein by different cVLP or different routes in order to avoid antibody activity against the cVLP that will neutralize repeated vaccination against the E6/E7 proteins, 2) in vitro immunization of human peripheral blood T cells with autologous DC loaded with cVLP expressing E6/E7 protein, 3) HPV VLP interaction and activation of human and mouse Langerhans cells, and 4) delivery of a new potential tumor suppressor gene or cytokine gene to cervical cancer cells and an antigen encoding gene or cytokine gene to dendritic cells. These combined aims will increase the potential and versatility of HPV VLP as therapeutic agents for HPV induced cervical cancer.