抗血管紧张素Ⅱ AT1受体抗体对大鼠脾脏T淋巴细胞的促增殖作用

目的观察抗AT1受体（AT1R）抗体对培养的大鼠脾脏T淋巴细胞增殖活性的影响。方法以人工合成的AT1R细胞外第二环肽段（AT1R—ECⅡ）为抗原主动免疫Wistar大鼠，利用亲和层析法提纯免疫大鼠血清中含有抗AT1R抗体的IgGs；培养大鼠脾淋巴细胞，刀豆蛋白A（ConA）诱导其活化和增殖，分别给予不同浓度的提纯IgGs（0．01、0．1、1umol／L）和血管紧张素Ⅱ进行干预，通过CCK-8法测定脾淋巴细胞增殖情况，并确定抗AT，R抗体的作用位点。结果ConA刺激48h后，大鼠脾淋巴细胞CCK-8吸光度显著高于空白对照组（0．38±0．05比0．27±0．02，P〈0．05）；不同浓度的IgGs剂量依赖性促进脾脏T淋巴细胞增殖（A值分别为0．53±0．03、0．71±0．04和0．94±0．05），与血管紧张素Ⅱ的作用相类似（A值为0．73±0．14、1．52±0．17和2．14±0．12）；AT1R特异性阻断剂Losartan和AT，R—ECⅡ均可显著减弱含抗AT1R抗体IgGs的促增殖效应（A值由0．71±0．04分别降为0．54±0．02，P〈0．01；0．52±0．04，P〈0．01）。结论抗AT1R抗体具有受体激动剂样效应，通过特异结合AT1R—ECⅡ剂量依赖性增强离体脾T淋巴细胞增殖活性。

Antibody against angiotensin AT1 receptor promotes proliferation of T lymphocytes from rats' spleen

Objective To investigate the effect of antibody against angiotensin Ⅱ AT1 receptor （AT1-RA） on proliferation of T lymphoeytes from rats＇ spleen in vitro. Methods Health adult rats were actively immunized with the synthetic peptide corresponding to the sequences for the second extracellular loop of AT1 receptor （AT1R- EC Ⅱ ）. The total IgGs in immunized rats＂ serum, containing quantity of AT1-RA, were purified with anti-rat IgG affinity column. Lymphoeytes isolated from rats＇ spleen and stimulated by Con A were treated with different concentrations of AT1-RA （0.01 umol/L,0.1 umol/L, 1 umol/L） or angiotensin II respectively, CCK-8 was used to detect the lymphocytes＇ proliferation response. In addition, the binding site of AT1-RA reacting with lymphocytes was determined. Results After 48 h, CCK-8 A value of lymphoeytes that reacted with Con A increased significantly compared with that of cells without Con A. All three different concentrations of AT1-RA could enhance the proliferation response of T lymphocytes from rats＂ spleen （A value,0.53±0.03,0.71±0.04, 0.94±0.05）. These effects of AT1-RA were almost identical with that of angiotensin Ⅱ （A values,0.73±0.14, 1.52±0.17,2.14±0.12）. Either Losartan or AT1R-EC Ⅱ attenuated the proliferation response induced by AT1-RA （A value decreased from 0.71± 0.06 to 0.54±0.02,P〈0.01 ;0.52±0.04, P〈0.01 ,respectively）. Conclusion Antibody against AT1R presenting an agonist-like activity could promote proliferation of T lymphocytes from rats＇ spleen in a dose-dependent fashion by interacting with AT1R-EC Ⅱ specially.