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本研究探讨了凝集素美洲商陆(PWM)激活的人外周血单核细胞介导的细胞毒活性作用的机制。通过采用DNA电泳和PI-DNA染色流式细胞仪检测,我们发现在凝集素依赖的单核细胞介导的细胞毒作用(LDMC)中,靶细胞U937细胞和Raji细胞呈现出细胞凋亡现象。这种LDMC诱导的U937细胞的DNA断裂现象可被抗TNF-α单克隆抗体所阻止,但不能被单糖N-乙酰基葡萄糖胺(GlcNAc)所抑制。相反,GlcNAc可抑制LDMC诱导的Raji细胞的DNA断裂,而抗TNF-α单抗对此却无作用。PWM可以刺激单核细胞产生活性一氧化氮(NO),这种刺激作用在Raji靶细胞存在时可被加强,但这种加强作用可被GlcNAc所阻断。通过流式细胞仪分析发现PWM可与单核细胞和肿瘤细胞结合。这些结果提示,单核细胞和肿瘤细胞上存在的凝集素类受体可促使两种细胞之间在凝集素介导下相互接近,并通过诱发单核细胞产生细胞毒因子(TNF和NO),促进诱导靶细胞的细胞凋亡。
This study explored the mechanism of lectin-mediated activation of human peripheral blood mononuclear cell-mediated cytotoxic activity in P. amurensis (PWM). By using DNA electrophoresis and PI-DNA staining flow cytometry, we found that in lectin-dependent monocyte-mediated cytotoxicity (LDMC), target cells U937 cells and Raji cells exhibited apoptosis. This LDMC-induced U937 cell DNA fragmentation can be prevented by anti-TNF-α monoclonal antibodies but not by monosaccharide N-acetylglucosamine (GlcNAc). In contrast, GlcNAc inhibits DNA fragmentation in LDMC-induced Raji cells, whereas anti-TNF-α mAbs have no effect on this. PWM can stimulate monocytes to produce active nitric oxide (NO). This stimulation can be enhanced in the presence of Raji target cells, but this potentiation can be blocked by GlcNAc. Through flow cytometry analysis, it was found that PWM can bind to monocytes and tumor cells. These results suggest that the presence of lectin-like receptors on monocytes and tumor cells may cause the two cells to approach each other under the lectin-mediated approach and induce monocyte production of cytotoxic factors (TNF and NO). Promotes induction of apoptosis in target cells.