AIM:To study whether heat-shocked tumor cells couldenhance the effect of tumor cell lysate-pulsed dendriticcells(DCs)in evoking anti-tumor immune response invivo.METHODS:Mouse undifferentiated colon cancer cells(CT-26)were heated at 42℃ for 1h and then frozen-thawed.The bone marrow-derived DCs pulsed with heat-shocked CT-26 cell lysate(HSCT-26 DCs)were recruitedto immunize syngeneic na(?)ve BALB/c mice.The cytotoxicactivity of tumor specific cytotoxic T lymphocytes(CTLs)in mouse spleen was evaluated by IFN-enzyme-linkedimmunospot(ELISpot)and LDH release assay.Theimmunoprophylactic effects induced by HSCT-26 DCsin mouse colon cancer model were compared to thoseinduced by single CT-26 cell lysate-pulsed DCs(CT-26DCs)on tumor volume,peritoneal metastasis andsurvival time of the mice.RESULTS:Heat-treated CT-26 cells showed a higherhsp70 protein expression.Heat-shocked CT-26 cell lysatepulsing elevated the co-stimulatory and MHC-II moleculeexpression of bone marrow-derived DCs as well asinterleukin-12 p70 secretion.The IFN-γ secreting CTLsinduced by HSCT-26 DCs were significantly more thanthose induced by CT-26 DCs(P=0.002).The formerCTLs’specific cytotoxic activity was higher than the latterCTLs’at a serial E/T ratio of 10:1,20:1,and 40:1.Mousecolon cancer model showed that the tumor volumeof HSCT-26 DC vaccination group was smaller thanthat of CT-26 DC vaccination group on tumor volumethough there was no statistical difference between them (24 mm~3 vs 8 mm~3,P=0.480).The median survival timeof mice immunized with HSCT-26 DCs was longer thanthat of those immunized with CT-26 DCs(57 d vs 43 d,P=0.0384).CONCLUSION:Heat-shocked tumor cell lysate-pulsedDCs can evoke anti-tumor immune response in vivoeffectively and serve as a novel DC-based tumor vaccine. AIM: To study whether heat-shocked tumor cells couldenhance the effect of tumor cell lysate-pulsed dendritic cells (DCs) in evoking anti-tumor immune response invivo.METHODS: Mouse undifferentiated colon cancer cells (CT- 26) 1h and then frozen-thawed.The bone marrow-derived DCs pulsed with heat-shocked CT-26 cell lysate (HSCT-26 DCs) were recruitedto immunize syngeneic na (?) Ve BALB / c mice. Cytotoxicactivity of tumor specific cytotoxic T lymphocytes (CTLs) in mouse spleen was evaluated by IFN-enzyme-linked immunospot (ELISpot) and LDH release assay. The immunoprophylactic effects induced by HSCT-26 DCsin mouse colon cancer model were compared to those induced by single CT-26 cell lysate-pulsed DCs CT-26DCs) on tumor volume, peritoneal metastasis and vulvarival time of the mice. RESULTS: Heat-treated CT-26 cells showed a higherhsp70 protein expression. Heat-shocked CT-26 cell lysatepulsing elevated the co-stimulatory and MHC-II moleculeexpression of bone marrow-derived DCs as well asi nterleukin-12 p70 secretion.The IFN-γ secreting CTLs induced by HSCT-26 DCs were significantly more thanthose induced by CT-26 DCs (P = 0.002) .The former CTLs’specific cytotoxic activity was higher than the latterCTLs’at a serial E / T ratio of 10: 1, 20: 1, and 40: 1. Mousecolon cancer model showed that the tumor volume of HSCT-26 DC vaccination group was smaller thanthat of CT-26 DC vaccination group on tumor volumethough there was no statistical difference between them (24 mm ~ 3 vs 8 mm ~ 3, P = 0.480). The median survival time of mice immunized with HSCT-26 DCs was longer thanthat of those immunized with CT-26 DCs (57 d vs 43 d, P = 0.0384). CONCLUSION: Heat-shocked tumor cell lysate-pulsed DCCs can evoke anti-tumor immune response in vivoeffectively and serve as a novel DC-based tumor vaccine.