Background: Despite recent advances in early detection and improvements in chemotherapy for colon cancer, the\npatients still face poor prognosis of postoperative recurrence and metastasis, the median survival for patients\nwith metastatic colorectal cancer is approximately 22ââ?¬â??24 months. Some immunotherapeutic approaches had\nbeen attempted in colon cancer patients to significantly increase overall survival. A vaccine based approach\nhas shown a novel direction for colon cancer prevention and therapy.\nMethods: In this study, the experiments were designed including prevention and therapeutic stages in order to attain\neffect against tumor recurrence in clinical settings. The anti-tumor efficacy of a novel cytokine adjuvant vaccine that\ncontained cytokines GM-CSF and IL-2 and inactivated colon CT26.WT whole cell antigen was evaluated in BALB/c mouse\ntumor models by measuring tumor growth post vaccination and the survival time of tumor-bearing mice, analyzing the\nexpression and distribution of CD4, CD8, CD11c, CD80, CD86 and CD83 positive cells in control and treated mice by flow\ncytometry and immunochemistry. The tumor-specific cytotoxic T cells (CTL) were analyzed by tumor proliferation and\nthe lactic dehydrogenates (LDH) release assays. IFN-Ã?³, IL-2 and GM-CSF secretion in serum was assayed by ELISA.\nResults: Our results suggested that cytokine adjuvant vaccine significantly inhibited tumor growth and extended\nthe survival period at least 160d. It was found that the levels of CD8 + T and the tumor-specific cytotoxicity were\nsignificantly higher in prevention and treatment group vaccinated by cytokine adjuvant vaccine. CD8 + T cells\nplay a key role in anti-tumor response.\nConclusions: The novel GM-CSF and IL-2 based adjuvant vaccine effectively activated autologous T-cell response\nand represented a promising immunotherapeutic approach for patients with colon cancer.
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