Hsp70-H22肿瘤抗原肽复合物激活树突状细胞诱导抗肿瘤免疫的研究

目的　探讨通过树突状细胞 (DC)提呈途径降低肿瘤抗原肽用量的可行性 ,了解热休克蛋白 70 (Hsp70 )和抗原肽修饰DC作用的特点。方法　以Hsp70于体外结合抗原肽 ,并于体外修饰DC ,检测修饰后DC的代谢活性及分泌的细胞因子 ;比较修饰后DC和Hsp70 H2 2肽对淋巴细胞的激活作用 ;检测激活的淋巴细胞对H2 2瘤细胞的细胞毒作用以及注射DC和Hsp70 H2 2肽对小鼠肿瘤的抑制作用。结果　Hsp70结合 0 .15 μgH2 2肽可使 2× 10 5DC成熟 ,4× 10 3 成熟DC可激活 2× 10 6淋巴细胞 ;Hsp70结合 0 .0 0 3μg肽修饰的DC或Hsp70结合 0 .15 μg肽直接刺激 ,可激活相同数量的淋巴细胞 ,产生同样的杀瘤效果。激活DC后再回输的治疗方式与直接注射Hsp70 肽复合物的治疗方式相比 ,抗原肽的用量可以降低 5 0倍。正常肝组织来源的混合肽结合Hsp70后 ,不能使DC成熟 ,亦不能通过DC途径活化脾淋巴细胞。结论　DC提呈抗原肽激活淋巴细胞的途径能够有效降低Hsp70 肿瘤抗原肽复合物使用剂量。正常细胞的混合肽不能通过Hsp70和DC提呈激活淋巴细胞 ,其诱发自身免疫应答的可能性极低

Hsp70-H22 tumor antigen peptide complex activated dendritic cell in the induction of antitumor immunity

OBJECTIVE: To investigate the feasibility of reduction in tumor antigen peptide dose by dendritic cell (DC)-presenting so as to elucidate the characteristics of modifying DC by heat shock protein (Hsp70) and antigen peptide. METHODS: Antigen peptide bound to Hsp70 was used to modify DC in vitro. The metabolism of the modified DC and the cytokine secreted thereby was determined. Then the activation of lymphocytes by the modified DC and Hsp70-H22 peptide was tested. The cytotoxicity of the activated lymphocytes to H22 tumor cells and the inhibition of tumor in mice by DC injection and Hsp70-H22 peptide was tested. RESULTS: 0.15 micro g of H22 peptide bound to Hsp70 could mature 2 x 10(5) DC. 4 x 10(3) matured DC could activate 2 x 10(6) lymphocytes. The same amount of lymphocyte could be activated to produce similar cytotoxicity to tumor cells by either DC modified by 0.003 micro g of peptides bound with Hsp70 or by direct stimulation with 0.15 micro g of peptides bound to Hsp70. The dose of peptide could be reduced to 1/50 if the modified DC injection was used instead of direct Hsp70-peptide injection. Peptide from the normal hepatocytes, if bound to Hsp70, could not mature DC, nor could it activate lymphocytes through DC. CONCLUSION: The dose of Hsp70-H22 peptides can be reduced significantly by DC-presenting to activate lymphocytes. Peptides from normal cells, being unable to activate the lymphocytes by either Hsp70-presenting or DC-presenting, have little to offer in the induction of autoimmunity.