中文摘要：

目的：研究没食子儿茶素没食子酸酯（epigallocatechin gallate，EGCG）对紫外线抑制树突状细胞的细胞免疫功能的保护作用。方法：分离外周血单核细胞，用细胞因子诱导树突状细胞（DC）成熟后，使用不同剂量的中波紫外线（UVB）照射，分别将EGCG处理或未处理的DC与T淋巴细胞进行混合培养，72h后用MTT法检测DC刺激T淋巴细胞增殖的能力。结果：UVB以剂量依赖性方式抑制DC刺激自体T淋巴细胞增殖能力，当UVB剂量大于10mJ／cm^2时抑制率即可达100％，使用浓度为200ug／mL的EGCG处理DC后，各剂量组UVB所致的免疫抑制作用则可得到部分改善。结论：紫外线可以直接抑制DC的免疫功能，EGCG具有拮抗紫外线抑制DC细胞免疫的功能。

英文摘要：

Objective To investigate the protection effect of epigallocatechingallate（EGCG）on the immune function of dendritic cells（DCs） after UVB irradiation. Methods The monocytes were isolated from peripheral blood and cultivated into DCs with cytokines such as GM-CSF and IL-4. DCs were harvested after culture for 7days and irradiated by different dose of UVB.200μg/ml EGCG was added in certain groups immediately after UVB irradiation. T lymphocytes were co-cultured with DCs which were irradiated only by UVB or treated by both UVB irradiation and EGCG. MTT assay was used to detect the ability of DCs stimulating lymphocytes to proliferate. Results UVB irradiation inhibited the ability of DCs stimulating lymphocyte proliferation in a dose-dependence. The inhibition rate reached 100% when UVB dose was higher than 10mJ/cm^2. The inhibition rate of DCs was improved to some degree, respectively after treated with 200μg/mL EGCG. Conclusion The irradiation of UVB inhibits cellular immune function of DCs directly. EGCG can antagonize such an immunosuppression induced by UVB irradiation.