Nanovaccine System for Cancer Immunotherapy

   Immunity is a mechanism that protects the body from infections such as viruses and bacteria. Cancer immunotherapy is the application of immunity, which is intrinsic body's defense mechanism, to the treatment of cancer. If cancer immunotherapy can be established, it is expected to become the highly safe and personalized treatment.
　Target-specific immunity induction occurs when antigen-presenting cells, mainly dendritic cells, present antigens for identifying abnormal cells to immunocompetent cells. Antigen presentation by antigen-presenting cells involves two types of molecules: MHC class I or class II. When an antigen is taken up by an antigen-presenting cell through phagocytosis, it is processed into peptide fragments in intracellular endosomes/lysosomes and presented on MHC class II molecules on the cell. Antigens presented on MHC class II molecules are recognized by helper T cells, leading to the induction of humoral immunity. When antigens are delivered in the cytosol of antigen-presenting cells, they are processed by proteasomes into peptide fragments, which are then presented on MHC class I molecules on the cells. Antigens presented on MHC class I molecules activate cytotoxic T cells, leading to the induction of cellular immunity.

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　In cancer immunotherapy, cellular immunity plays an important role in eliminating abnormal cells such as cancer cells. Therefore, to realize cancer immunotherapy, it is essential to develop an antigen delivery system that delivers foreign antigens to the cytosol of antigen-presenting cells and induces cellular immunity through antigen presentation via the MHC class I pathway. We are conducting research on nanovaccine systems that use functional liposomes to deliver antigens to appropriate locations within cells and effectively induce immunity. We are also working to improve the performance of liposomes by incorporating various functional molecules that activate cancer immunity into them.


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