Review: the application of dendritic cell-derived exosomes in tumour immunotherapy.

Cancer arises from the aberrant proliferation of a single transformed cell. This population acquires the ability to metastasis. An effective way to remove cancer cells from the body is to activate tumour-specific cytotoxic T cells (CTL). Activation of naive T cells depends on the unique antigen presenting capacity of DC. Activated tumour antigen-specific CTL can destroy cancer cells without harm to normal tissue. Their ability to stimulate antigen specific T cell responses makes DC attractive candidates to potentiate anti-tumour immunity. Several studies have demonstrated the efficacy of DC based anti-tumour immunotherapy and the goal now is to optimise immune responses induced by DC, so that effective strategies in treating cancer may be realised. One way to do this is to identify DC characteristics which make them more effective in T cell stimulation. Another is to use exosomes, the antigen presenting vesicles secreted by DC, in order to induce potent anti-tumour immune responses. The non-cellular nature of exosomes offers several advantages for use in tumour immunotherapy.