HIFU治疗后肿瘤抗原对树突状细胞的活化及其抗肿瘤效应

Anti-tumor immunity induced by activated dendritic cells with tumor antigen from HIFU-treated tumors

目的:探讨HIFU治疗小鼠H22抑制性肝癌后产生的肿瘤抗原对机体抗肿瘤免疫功能增强的机制。方法:正常小鼠骨髓中提取骨髓细胞,在rmIL-4、rmGM-CSF条件下培养7 d,制备小鼠骨髓树突状细胞,用HIFU治疗小鼠移植性肝癌后产生的肿瘤抗原活化树突状细胞,再用活化后的树突状细胞激活T淋巴细胞为细胞毒性T细胞,用MTT法检测CTL在体外特异性杀伤肿瘤靶细胞的能力。结果:B16肿瘤HSP70-肽复合物组和H22肿瘤HSP70-肽复合物组的脾淋巴细胞的增殖率均高于阴性对照组、H22肿瘤粗提物组和HIFU后H22肿瘤粗提物组,P<0.001;但两组之间差异无统计学意义,P>0.05。H22肿瘤HSP70-肽复合物组CTL对H22肿瘤细胞的杀伤率为70.0%,明显高于阴性对照组、H22肿瘤粗提物组和HIFU后H22肿瘤粗提物组(P<0.001),但对非靶细胞B16肿瘤的杀伤率与上述各组的差异无统计学意义;B16肿瘤HSP70-肽复合物组CTL对B16肿瘤细胞的杀伤率为78.5%,对H22细胞的杀伤率为21.4%,表明CTL对肿瘤细胞的杀伤作用具有特异性。结论:HIFU治疗后坏死肿瘤组织中的HSP70-肽复合物作为肿瘤疫苗,通过活化DC和刺激T淋巴细胞增殖为CTL,发挥特异性抗肿瘤免疫功能。

OBJECTIVE： To explore the mechenism of tumor antigen which is H22 hepatic carcinoma treated with high intensity focused ultrasound （HIFU） to reinforce the anti-tumor immunity. METHODS： Myeloeytes derived from normal mice were cultured with rmIL-4 and rmGM-CSF for 7 days to extract myeloid dendritic cells （DCs）, and tumor antigen from HIFU-treated tumors activated DCs and cytotoxic T lymphocytes （CTL） were obtained by stimulating T lymphocytes with activated DCs, and CTL specific cytotoxicity against H22 tumor cells was measured in vitro. RESULTS： Spleen lymphocyte proliferation rates were significantly higher in H22 HSP70-peptide complex group and B16 HSP70-peptide complex group than those in serum group, H22 tumor supernatant group and H22 treated tumor supernatant group, P〈 0. 001; but no significant difference was observed between B16 HSP70-peptide complex group and HSP70-peptide complex group, P〉0.05. CTL cytotoxieity against H22 tumor cells was 70.0%, which was significantly higher than those in serum group, H22 tumor supernatant group and H22 treated tumor supernatant group, P〈0. 001, but no statistical difference was observed in CTL cytotoxicity against B16 tumor cells among these four groups. CTL eytotoxieity against B16 tumor cells was 78.5%, and the cytotoxicity against H22 tumor cells was 21.4% in B16 HSPT＆peptide complex group, indicating that CTL cytotoxicity original from HIFU-treated tumor had specific anti-tumor immunity. CONCLUSIONS： HSP70-peptide complex purified from HIFUtreated tumor is a tumor vaccine. It could play an important role in host anti-tumor immunity by activating immature DCs, stimulating T lymphocyte proliferation, and inducing CTL production.