抗幽门螺杆菌尿素酶B单抗对人血小板聚集与活化的影响及其机制研究

Effect of anti-helicobacter pylori ureB monoclonal antibody on platelet aggregation and activation,and its mechanism study

目的研究抗幽门螺杆菌尿素酶 B(Hp ureB)单克降抗体(1F11)对二磷酸腺苷(ADP)诱导的人血小板聚集与活化的影响及其机制。方法采用 Western blot 分析血小板膜糖蛋白(GP)成分与 1F11的相关性,采用比浊法检测血小板聚集情况,分别用双抗夹心、抗原竞争的酶联免疫测定法检测各组中血浆中的 P-选择素、血栓烷 B_2。通过流式细胞术(FCM)分析单抗 1F11与 SZ21单抗对血小板 GPⅢa 的竞争性。结果 1F11与血小板成分 GPⅢa 有一定程度结合,1F11单抗可叫显抑制 ADP诱导的人血小板的聚集,随着1F11浓度的增加,血小板聚集抑制率呈剂量依赖性增高,但1F11并不抑制血浆中 P-选择素、血栓烷 B_2的水平。FCM 结果显示:加单抗1F11后可使 FITC-SZ21单抗与血小板结合的阳性细胞率从99.5%降至77.4%。结论 1F11可与人血小板 GPⅢa 结合并抑制血小板聚集,但不能阻止血小板的活化过程。Hp ureB 与人血小板 GPⅢa 具有交叉识别的抗原表位,提示幽门螺杆菌可能与 ITP 发病有关。

Objectives To study the effect of monoclonal antibody （McAb） against helicobaeter pyloft （Hp） ureB, 1F11 on platelet aggregation and activation, and its mechanism. Methods The relativity between human platelet glycoproteins（GPs） and Hp ureB was identified by Western blot and FCM. Platelet aggregation was measured by turbidimetry, and P-selectin and TXB： assay by ELISA. Results 1F11 could bind to platelet GP Ⅲ a, and ADP-induced platelet aggregation was inhibited by 1F11 in a dose-dependent manner. However, 1F11 had no effect on plasma P-selectin and TXB2 induced by ADP. The FCM results show that the positive rates of platelet binding to FITC-SZ21 was decreased from 99.5% to 77.4% after addition of 1F11. Conclusion McAb against Hp ureB 1 F11 inhibits platelet aggregation through binding to platelet GPⅢa but does not block platelet activation. There might be crossed-epitopes on Hp ureB and platelet GPⅢ a, and Hp infection might be involved in ITP immunopathology.