【摘要】 目的 观察健康人外周血白细胞中α-防御素和β-防御素基因表达的阳性率及外周血白细胞中α-防御素和β-防御素两大家族基因表达的特征,探讨其在感染免疫中的作用。方法 51名献血员被随机纳入研究中,在体外用100 ng/ml内毒素刺激其外周血白细胞,采用半定量逆转录-聚合酶链反应(RT-PCR)测定0、1、3、6、12、24 h时白细胞防御素信使RNA(mRNA)的水平,DNA印迹分析和序列测定法证实核苷酸扩增产物的特异性。结果 在无刺激时,所有研究对象的外周血白细胞均检测到α-防御素1-3 mRNA的转录,而无β-防御素mRNA的转录。内毒素刺激3 h后,88.2％研究对象的外周血可检测到β-防御素1 mRNA的转录,39.2％β-防御素2 mRNA表达阳性,并于刺激6 h时β-防御素1和2 mRNA水平达到峰值,而α-防御素1-3 mRNA的水平并无显著性改变。α-防御素1-3基因在外周血白细胞中呈持续性表达,而β-防御素1-2呈可诱导性表达,β-防御素1和2基因的可诱导性表达存在个体间差异。结论 α-防御素和β-防御素的不同表达特征与其基因调控顺式作用成分不同有关,提示两大类防御素在感染免疫中具有不同的作用。更多还原

【Abstract】 Objective To examine the expression of a- and β-defensin genes in human peripheral leukocytes. Methods Fifty-one healthy blood donors were studied. Peripheral leukocytes were stimulated by lipopolysaccharide ( LPS) 100 ng·ml-1 ex vivo. The level of defensin mRNA expression in the leukocytes were assessed after being incubated with LPS for 0 (baseline), 1, 3, 6, 12, 24 h by semi-quantitative RT-PCR. Southern blot analysis and sequencing were used to confirm the identity of defensin gene transcripts. Results Expression of α-defensin 1-3 mRNA was detected in all donors studied, but no β-defensin mRNA expression was detected in peripheral leukocytes before LPS-stimulation. Expression of β-defensin-1 gene was detected in the leukocytes after being incuaated with LPS for 3 h in 45 of 51 donors (88.2% ) and β-defensin-2 mRNA expression was positive in 20 donors (39.2 % ), but no β-defensin-3 mRNA expression was detected. The levels of β-defensin-1 and-2 mRNA peaked at 6 h and started decreasing at 12 h. In contrast there was no significant change in α-defensin 1-3 mRNA in peripheral leukocytes after LPS-stimulation. Conclusion In human peripheral leukocytes β-defensin-1 and-2 genes are induced transiently by LPS-stimulation;whereas α-defensin 1-3 genes are constitutive. The induced expression of β-defensin-1 and-2 genes show inter-individual variability.更多还原