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探讨小鼠髓系DC (CD8α )中PD L1和PD L2的表达及其在T淋巴细胞活化中的作用。采用mCD4 0L CHO和TNF α分别刺激凋亡肿瘤细胞负载DC 4 8h ;免疫荧光标记检测DC表型 ;RT PCR和realtime PCR检测PD L1和PD L2mRNA转录水平 ;ELISA测定IL 2的分泌水平 ;3 H TdR掺入试验和51Cr释放试验测定DC体外激发T细胞的增殖和细胞毒杀伤率。结果显示 :PD L1和PD L2随着DC的成熟呈上调表达 ,CD4 0配基化DC的PD L1和PD L2均为中度表达 ,TNF α激发的DC为高度表达 ,二者呈现差异性表达 (P <0 0 5 ) ;CD4 0配基化髓系DC分泌IL 2的量明显高于TNF α组 (P <0 0 5 ) ,体外刺激T增殖和激活CTL能力在CD4 0配基化DC组最高 (P <0 0 5 )。提示CD4 0配基化的小鼠髓系DC呈现PD L1和PD L2的中度表达 ,IL 2大量分泌 ,这些均有助于激发有效的特异性免疫应答
To investigate the expression of PD L1 and PD L2 in murine myeloid DC (CD8α) and its role in T lymphocyte activation. The apoptotic tumor cells were stimulated with mCD4 0L CHO and TNFα for 48 h, respectively. The DC phenotypes were detected by immunofluorescence staining. The transcriptional levels of PD L1 and PD L2 mRNA were detected by RT-PCR and real-time PCR. The levels of IL-2 secreted by 3 H TdR incorporation assay and 51Cr release assay were used to determine the proliferation and cytotoxicity of DC stimulated T cells in vitro. The results showed that: PD L1 and PD L2 were up-regulated with the maturation of DC, PD L1 and PD L2 were both moderately expressed in CD4 0-DCs, and were highly expressed in TNFα-stimulated DCs (P <0.05). The amount of IL 2 secreted by myeloid DCs with CD4 0 was significantly higher than that of TNFα (P <0.05), and the ability of stimulating T proliferation and activating CTL in vitro was significantly lower than that of CD4 0-DCs The highest group (P <0 05). It is suggested that the CD4 0 mouse myeloid DCs, which exhibit a moderate expression of PD L1 and PD L2 and a large secretion of IL 2, contribute to the elicitation of effective specific immune responses