【摘要】 目的 探讨1型糖尿病胰岛素缺乏机理及GAD-Ab对胰岛细胞结构及功能的影响。方法 以改良的放射配体法筛选1型糖尿病患者GAD-Ab阳性血清，以亲和层析法从该血清中分离纯化GAD-Ab，以免疫荧光法观察GAD-Ab与β-细胞的结合；将纯化的GAD-Ab及/或补体加入人胎胰岛细胞培养体系。结果 GAD-Ab能够与β-细胞结合，并使培养胰岛细胞的胰岛素释放量减少；透射电镜观察，加GAD-Ab组β-细胞胞浆颗粒减少；同时加入补体组β-细胞的细胞膜被破坏。结论 1型糖尿病患者血清GAD-Ab在体外能够抑制培养的人胎胰岛β-细胞的胰岛素合成和释放，并且有补体依赖性细胞毒作用。

    Effectofglutamicaciddecarboxylaseautoantiboyon insulin secretion Wang Jianmin,Zhou Zhiguang,Wu Hanwen.Institute of Metabolism & Endocrinology,Hunan Medical University,Changsha,410011

    【Abstract】 Objective To study the mechanism of insulin insufficiency in type 1 diabetes mellitus and to investigate the effect of glutamic acid decarboxylase autoantiboy (GAD-Ab) on structure and function of pancreatic islet cells. Methods Radioligand assay of GAD-Ab was used to select the positive sera of GAD-Ab in type 1 diabetes patients and affinity chromatography was used to purify GAD-Ab from the positive sera. Indirect immunofluorescent technique was used to observe the binding of GAD-Ab to islet beta cells. Cultured islet beta cells were incubated with GAD-Ab and/or complements and the released insulin was measured by radioimmunoassay. The structure of islet beta cells was observed with transmission electron microscope. Results The amount of released insulin in group C (incubated with GAD-Ab) was lower than those of the group A (control) and B (incubated with complement; both P<0.01); but it was higher than that of group D (incubated with GAD-Ab and complement) (P<0.01). There were no differences between the values of groups A and B (P>0.05). Granules in the cells of group C (incubated with GAD-Ab) were fewer than those in groups A (control) and group B (incubated with complement). In group D (incubated with GAD-Ab and complement) not only the granules were fewer, but also the cell membrane was distroyed. Conclusion GAD-Ab had influences both on insulin synthesis and release, it also had the complement-dependent cytotoxicity to human fetal islet beta cells cultured in vitro.

     ......