[目的]探讨系统性硬化病(SSc)患者外周血CD4+T细胞中CD40L基因调控序列的甲基化状态.[方法]密度梯度离心法分离SSc患者(女16例,男10例)和健康对照组(女15例,男10例)外周血单一核细胞,磁珠分选CD4+T细胞,提取DNA,亚硫酸氢钠处理DNA,巢式PCR扩增CD40L基因调控序列片段(包括启动子和增强子),转化进入大肠杆菌,每个样本挑取8个克隆进行测序.[结果]亚硫酸盐基因组测序结果显示,健康女性CD40L基因调控序列一半为甲基化,一半为去甲基化,女性SSc患者CD40L基因启动子和增强子区域平均甲基化水平均显著低于女性健康对照(P值均＜ 0.01)；男性SSc患者和男性健康对照CD40L基因启动子和增强子区域几乎全部为去甲基化,两组平均甲基化水平差异无统计学意义(P值均＞0.05).[结论]女性SSc患者CD4+T细胞中失活的X染色体上CD40L调控序列低甲基化,可能是导致CD40L在女性SSc患者CD4+T细胞中过度表达的原因之一.

目的: 测定多聚核糖体含量及多聚程度的分布.方法:采用PRV-50T垂直转头40PA离心管,梯度为15%-55%连续蔗糖梯度.离心条件:温度10℃,转速40 000 r/min,时间9min.DGF-U型梯度仪液面跟踪法收集,同时与TH641摆平转头进行对比.结果:采用垂直转头具有分离效果好,重现性强,操作简单,特别是离心管体积大,离心过程中产生的重定向作用使梯度容量大大增加,分离路径大大缩短,时间相应减少.结论:为快速和大量制备、分析多种多聚核糖体提供一种良好方法.

The present study was undertaken to investigate the effect of human PMNs on the production of TNF-α by the human peripheral blood mononuclear cells (PBMCs) and to elucidate its tentative mechanism. Human PMNs and PBMCs were isolated from the venous blood of healthy donors by dextran sedimentation and density gradient centrifugation. In the presence of lipopolysaccharide (LPS), PMNs and PBMCs were cocultured at the ratio of 2:1 for 20 h and the concentration of TNF-α in the supernatant was measured by enzyme-linked immunosorbent assay. The binding rate of monocytes with the fluorescein isothiocyanate-labeled LPS (FITC-LPS) and the mean surface fluorescence intensity of monocytes were analyzed by flow cytometry. Results showed that PMNs were capable of inhibiting the TNF-α release from PBMCs (P＜0.05). PMNs suppressed the TNF-α release from PBMCs by 45% on average when PMNs and PBMCs cocultured at the ratio of 2:1. Paraformaldehyde-fixed PMNs still demonstrated the same inhibition (P＜0.05)，which proved that the inhibition was dependent on cell-to-cell contact and suggested that effector molecules responsible for this effect existed on the cell surface of PMNs. In the presence of PMNs, the binding rate of monocytes with the FITC-LPS and the mean surface fluorescence intensity of monocytes were not affected compared with PBMCs alone (P＞0.05). As incubation time was prolonged, the binding of FITC-LPS to monocytes increased (P＜0.05). Thus PMNs did not block the binding of LPS with monocytes. It was concluded that PMNs suppressed the TNF-α release from PBMCs via cell-to-cell interaction. In a cell-contact dependent manner, PMNs might interfere with the signal transduction pathway through which LPS activated PBMCs, thus attenuating the response of PBMCs to LPS and downregulating the TNF-α release.