1.Introduction of the CIITA gene into tumor cells produces exosomes with enhanced anti-tumor effects.
Yeong Shin LEE ; Soo Hyun KIM ; Jung Ah CHO ; Chul Woo KIM
Experimental & Molecular Medicine 2011;43(5):281-290
Exosomes are small membrane vesicles secreted from various types of cells. Tumor-derived exosomes contain MHC class I molecules and tumor-specific antigens, receiving attention as a potential cancer vaccine. For induction of efficient anti-tumor immunity, CD4+ helper T cells are required, which recognize appropriate MHC class II-peptide complexes. In this study, we have established an MHC class II molecule-expressing B16F1 murine melanoma cell line (B16F1-CIITA) by transduction of the CIITA (Class II transactivator) gene. Exosomes from B16-CII cells (CIITA-Exo) contained a high amount of MHC class II as well as a tumor antigen TRP2. When loaded on dendritic cells (DCs), CIITA-Exo induced the increased expression of MHC class II molecules and CD86 than the exosomes from the parental cells (Exo). In vitro assays using co-culture of immunized splenocytes and exosome-loaded DCs demonstrated that CIITA-Exo enhanced the splenocyte proliferation and IL-2 secretion. Consistently, compared to B16-Exo, CIITA-Exo induced the increased mRNA levels of inflammatory cytokines such as TNF-alpha, chemokine receptor CCR7 and the production of Th1-polarizing cytokine IL-12. A tumor preventive model showed that CIITA-Exo significantly inhibited tumor growth in a dose-dependent manner. Ex vivo assays using immunized mice demonstrated that CIITA-Exo induced a higher amount of Th1-polarized immune responses such as Th1-type IgG2a antibodies and IFN-gamma cytokine as well as TRP2-specific CD8+ T cells. A tumor therapeutic model delayed effects of tumor growth by CIITA-Exo. These findings indicate that CIITA-Exo are more efficient as compared to parental Exo to induce anti-tumor immune responses, suggesting a potential role of MHC class II-containing tumor exosomes as an efficient cancer vaccine.
Animals
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Cancer Vaccines/genetics/immunology
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Cell Line, Tumor
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Cell Proliferation
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Dendritic Cells/immunology
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Exosomes/genetics/*metabolism
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Gene Expression Regulation
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Gene Transfer Techniques
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Immunity, Cellular/immunology
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Immunity, Humoral/immunology
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Immunotherapy
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Lymphocyte Activation/immunology
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Melanoma, Experimental/mortality/pathology/*physiopathology
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Mice
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Mice, Inbred C57BL
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Nuclear Proteins/*genetics/*metabolism
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Survival Analysis
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T-Lymphocytes/immunology/metabolism
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Trans-Activators/*genetics/*metabolism
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Transduction, Genetic