树突状细胞负载甲胎蛋白、细胞毒性T细胞表位肽后的免疫应答

目的 用负载hAFP 218-226位LLNQHACAV九肽的树突状细胞（dendritic cells,DC)诱导自身淋巴细胞，使之活化为肝细胞癌（HCC）特异性细胞毒性T细胞（cytotoxic T lymphocyte,CTL)，并特异性杀伤HCC细胞。方法 在体外用GM-CSF和IL-4诱导HLA-A2^ 健康志愿者外周血单核细胞，使其分化为高纯度DC。用负载hAFP 218-226位LLNQHACAV九肽的DC诱导自身淋巴细胞，使之成为HCC特异性CTL。结果 诱导的DC分泌较高水平的IL-12（17.6-21.5pg/ml)，其中以第7天为最高（21.5pg/ml)，经DC和DC负载AFP表位肽后活化的淋巴细胞培养上清液中TNF水平均比在IL-2条件下培养的未活化淋巴细胞高。L929细胞死亡百分率分别为80.65和11.6%；经DC和DC负载AFP表位肽后活化的淋巴细胞培养上清液中IL-12水平分别为20.5pg/ml和46.9pg/ml，经DC活化后淋巴细胞增殖指数大于3。活化后的淋巴细胞不但特异性杀伤HLA-A2^ 的HCC细胞HepG2和负载AFP表位肽的T2细胞，而且还不同程度杀伤HLA-A3^ HCC细胞Alexander和其它表型HCC细胞，对NK细胞敏感的靶细胞慢性髓原白血病细胞K562也有较强的杀伤作用。结论 负载hAFPHLA-A2限制性CTL九肽的DC对表达AFP HCC的研究和治疗有潜在应用价值。

Immune responses of dendritic cells after loaded with cytotoxicity T lymphocyte epitope based peptide of human α -feto-protein (hAFP)

OBJECTIVE: To study the immune responses of lymphocytes after activated by dendritic cells (DCs) loaded with cytotoxicity T lymphocyte (CTL) epitope based peptide of human alpha-fetoprotein (hAFP, 218-226 LLNQHACAV). METHODS: Get high purity DCs by cultured plastic-adherent monocytes isolated from healthy donor of HLA-A2(+) peripheral blood with granulocyte-monocyte colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 7 days. Stimulate self-lymphocytes with DCs that loaded with CTL epitope based peptide of hAFP under the culture medium contains interleukin-2 (IL-2) for 7 days. Analyse IL-12 and TNF in culture medium and also the specific lysis activity of lymphocytes against four strains of primary hepatocellular carcinoma cells. RESULTS: After stimulated by DC loaded with CTL epitope based peptide derived from hAFP, lymphocytes appeared a good characteristics and the culture medium of activated lymphocytes contained a high level Th1 type cytokines of IL-12 and TNF. Activated lymphocytes not only specifically lysed HLA-A2(+) HepG2 line but also had the cytotoxicity against other three primary hepatocellular carcinoma cell lines and T2 target cell loaded with peptide of hAFP. CONCLUSIONS: The results of this research supply the basic materials for the DC based vaccine with HLA-A2 restricted peptide epitope derived from hAFP against AFP positive primary hepatocellular carcinoma.