血管紧张素Ⅱ-1型受体抗体的制备及其生物效应检测

目的 利用主动免疫方法 在大鼠血清中制备AT1受体的抗体并检测其对心血管系统的生物效应,以探讨血管紧张素Ⅱ-1型（AT1）受体的抗体与心血管疾病的关系.方法 按照人AT1受体细胞外第二环表位肽段合成抗原肽段,以此对大鼠进行主动免疫,获取抗AT1受体抗体,并提纯抗体IgG,检测该抗体对大鼠血管环和离体心脏的生物效应.结果 ELISA检测表明,抗体滴度从免疫后第2周开始升高,第8周滴度达到一个高峰;PAGE凝胶电泳检测显示纯化结果 理想.AT1受体抗体可剂量依赖性地使大鼠主动脉血管环收缩增加,使离体灌流心脏的收缩和舒张功能增强.上述效应与血管紧张素Ⅱ的作用一致,并可被AT1受体阻断剂Losartan所阻断.结论 用主动免疫法可在大鼠血清中获取足量AT1受体抗体,借以研究其生物效应.AT1受体抗体对大鼠主动脉血管环和离体心脏均有激动剂样的刺激效应,提示该抗体可能与心血管疾病的发病有关.

Preparation of antibody against angiotensin AT1 receptor and determination of its biological activities

Objective To clarify the role of antibody against angiotensin AT1 receptor in the pathogenesis of cardiovascular diseases, we prepared the anti-AT1 receptor antibody （AT1-R Ab） in the sera of rat by active immunization and detected its biological activities. Methods The AT：R Ab was derived by immunizing rats with synthetic peptide corresponding to the sequence of the second extracellular loop of human AT1 receptor, the anti- body IgG was purified and their effects on vascular contraction and cardiac function were examined. Results The antibody titre by ELISA assay began to increase from the 2nd week and reached a peak at the 8th week after immunization. PAGE assay showed a satisfied purification. The AT1-R Ab dose-dependently increased the vascular contractile tension and the ex vivo cardiac function of isolated rat heart. Ang- Ⅱ showed similar increasing effects as those of ATI-R Ab. Both effects could be blocked by Losartan, a specific antagonist of AT1-receptor. Conclusion A sufficient AT1-R Ab can be obtained from the sera of rat after active immunization. The ATrR Ab shows agonist-like stimulatory effects on aortic vascular ring and ex vivo cardiac function in rats, suggesting a possible involvement of AT1-R Ab in the pathogenesis of cardiovascular diseases.