负载核糖体蛋白L8的树突状细胞对黑色素瘤的抑制作用

背景与目的：研究发现核糖体蛋白L8(ribosomal protein L8，RPL8)在黑色素瘤中表达能激活黑色素瘤患者外周血单个核细胞增殖并产生白细胞介素2，提示RPL8可能参与抗肿瘤免疫应答，有望成为抗肿瘤治疗的靶点。本研究通过RPL8蛋白负载树突状细胞(dentritic cell，DC)，探讨负载RPL8蛋白的DC对黑色素瘤的免疫效应。方法：原核表达RPL8蛋白，纯化后致敏小鼠骨髓来源DC，流式细胞仪检测DC表面标志，MTT法检测细胞毒性T淋巴细胞对小鼠黑色素瘤细胞的杀伤作用；负载RPL8蛋白DC免疫治疗小鼠后，观察肿瘤体积变化及小鼠生存时间。结果：纯化蛋白经蛋白质印迹法(Western blot)分析见约28×103大小的特异性条带；DC经RPL8及细菌脂多糖(Lipoplysaccharide，LPS)诱导成熟后细胞表面CD11c、CD80、MHC-Ⅰ类、MHC-Ⅱ类分子表达增高，能激活T淋巴细胞，对B16细胞有抑制作用，RPL8-DC组的抑制率在效靶比为30∶1时高达70%，较PBS组和DC组明显增高；负载RPL8蛋白DC免疫治疗小鼠后，肿瘤体积缩小，小鼠的生存期明显延长。结论：负载RPL8的DC对黑色素瘤有生长抑制作用。

Experimental study of the anti-melanoma effect of dentritic cells pulsed with RPL8 peptide

［Abstract］ Background and purpose: Studies have shown that ribosomal protein L8 (RPL8) is shared by melanomas, gliomas and ovarian carcinomas. A peptide of RPL8 significantly stimulated proliferation and cytokine expression of the hepler T cell clone and lymphocytes in melanoma patients. RPL8 may stimulate anti-tumor immunity, making RPL8 an attractive candidate for therapeutic intervention. In this study, we prepared DC pulsed by RPL8 (RPL8-DC) and investigate the anti-tumor effect of RPL8-DC on melanoma in mice. Methods: The recombinant protein was achieved through IPTG induction in E. coli and identified with Western blot. Bone marrow-derived DC was loaded with RPL8 protein. RPL8 and CD11c, CD80, MHC-Ⅰ, MHC-Ⅱ molecules on dentritic cells were monitored by fluorescence microscope and FACS analysis, respectively. The anti-tumor effect of T cells in vitro was detected by MTT assay. Subcutaneous tumors were induced in C57BL/6 mice using B16 cells. The tumor volumes were measured after injection with RPL8-DC. Results: The purified protein was combined with specific antibodies. DCs pulsed by RPL8 were visualized under fluorescent microscopy. CD11c, CD80, MHC-Ⅰ, MHC-Ⅱ molecules on DCs were up-regulated after stimulation with RPL8 and LPS. B16 cells were inhibited by T cells stimulated with RPL8-DC. The inhibition rate of tumor cells was 70% in RPL8-DC group when effector-to-target ratio was 30∶1, which was higher than PBS and DC groups. Inhibition of growth could be observed more significantly in mice after the treatment with RPL8-DC. The mice receiving the therapy of RPL8-DC were able to survive much longer than the mice receiving control therapy. Conclusion: The DC pulsed by RPL8 protein can inhibit the growth of melanoma.