重组V2毒素延长中性粒细胞的功能性生命期限

PROLONGATION OF THE FUNCTIONAL LIFE-SPAN OF NEUTROPHILS BY RECOMBINANT VEROTOXIN 2

目的 :揭示V毒素在溶血性尿毒症 (HUS)和其他与多源性大肠杆菌 (VTEC)相关疾病中的病理性损伤作用。方法 :运用流式细胞技术 ,荧光标记探针———BCECF AM和细胞色素C还原法测定超氧离子 (O- 2 )技术。结果 :重组V2毒素 (rVT2 )对中性粒细胞自发性凋亡有着显著性的抑制作用。被rVT2 延迟了凋亡的中性粒细胞仍然保留多种生物学活性 ,如 :细胞表面粘附分子的表达 (CD6 2L减少和CD11b CD18增加 ) ,粘附人脐带静脉血管内皮细胞 (HUVEC)以及产生超氧离子 (O-2 )。结论 :V2毒素延长中性粒细胞的功能性生命期限 ,会加重炎症局部的炎症反应 ,这可能是HUS和VTEC相关疾病的发生过程中 ,中性粒细胞介导的组织损伤的一个重要因素。

Objective: Verotoxin-producing Escherichia coli (VTEC) strains of serotype O157:H7 have been implicated as causes of a wide spectrum of diseases, raging from blood diarrhea and hemorrhagic colitis to hemolytic uremic syndrome (HUS). Recent studies have demonstrated that a direct cytotoxic effect of verotoxins (VTs) is related in the diseases. We previously reported the inhibitory effect of VT 2 on spontaneous apoptosis of neutrophils. To further reveal the pathological role of verotoxin (VT) in HUS and other VTEC-associated diseases, the effects of recombinant VT 2 (rVT 2) on the biological activities of neutrophils are investigated. Methods: The technique of FACS flow cytometer, a fluorescent probe-BCECF/ AM, and the assay of reduced cytochrome c to detect superoxide production were used in this study. Results: rVT 2 significantly inhibited spontaneous apoptosis of neutrophils. Neutrophils whose apoptosis had been delayed rVT 2 maintained various biological functions, such as expression of adhesion molecules (shading CD62L and raising CD11b/CD18), adherence to human umbilical vein endothelial cells (HUVEC), and generation of superoxide (O-2). Conclusion: Prolongation of the functional life-span of neutrophils by rVT 2 may accelerate inflammatory responses in sites of inflammation, which may play a crucial role in neutrophil-mediated tissue injury in HUS and other VTEC-associated diseases.