中文摘要：

目的分析OX40／OX40L分子在人活化T细胞上的表达特性及其生物学意义。方法采用激发型抗人CD3单抗、激发型抗人CD3单抗联合抗人CD28单抗、植物血凝素（PHA）以及抗原负载树突状细胞（DC）4种不同活化方式激发人T细胞，通过流式细胞仪和RT-PCR从蛋白水平和mRNA水平检测不同亚群T细胞上OX40和OX40L的表达；通过CCK-8法检测体外混合淋巴细胞反应。结果通过激发型抗人CD3单抗、激发型抗人CD3单抗联合抗人CD28单抗、PHA等非特异方式激发健康人外周血T细胞后，CD4^＋和CD8^＋T细胞上OX40和OX40L均呈短暂表达，而DC特异激发后上调表达的OX40和Ox40L则呈低水平持续表达，而且只表达在CD4^＋T细胞上。混合淋巴细胞反应结果显示健康志愿者T细胞活化24h后表达的OX40L能激发同种异体或自体活化T细胞上表达的OX40，从而促进T细胞增殖。结论特异和非特异方式活化的T细胞均能上调表达OX40和OX40L，但在表达水平、持续时间、表达的T细胞亚群上有所差异，且上调表达在T细胞上的OX40和OX40L具有生物学功能，能相互结合促进自身或邻近T细胞的增殖。

英文摘要：

Objective To analyze OX40/OX40L expression characteristics on activated human T cells and their biological significance. Methods After T cells were stimulated respectively with anti-CD3 mAb, anti-CD3 mAb plus anti-CD28 mAb, PHA or Daudi loaded mature DCs, OX40 and OX40L expression on different T cell subsets were tested by FACS and RT-PCR. A mixed lymphocyte reaction （MLR） using CCK-8 was performed in order to study the biological significance of OX40 and OX40L coexpression for T cells. Results After T cells were primed with anti-CD3 mAb, anti-CD3 mAb plusanti-CD28 mAb or PHA, 03：40 and OX40L molecules were expressed transiently on activated CD4^＋ and CD8^＋ T cells. Differently, OX40 and OX40L was detectable only on DCs-stimulated CD4^＋ T cells and their low expressions could be maintained for long time. The MLR showed that the activated T-cells pre-treated with MMC could stimulate the proliferation of allogeneic and autologous T-cells and anti-OX40L mAb could reduce it. Conclusion OX40 and OX40L were coexpressed on both specifically and nonspecifically activated T cells. However, the expression levels, times, and T cell subsets where these molecules were expressed were different. Moreover, the upregulated OX40 and OX40L may induce the reaction between T-T ceils to promote T cell proliferation, indicating these molecules have biological function.