Aaen K, Rygaard J, Josefsen K, Petersen H, Brogren C H, Horn T, Buschard K
Bartholin Institute, Kommunehospitalet, Copenhagen K, Denmark.
Diabetes. 1990 Jun;39(6):697-701. doi: 10.2337/diab.39.6.697.
Antigen expression corresponding to anti-islet cell surface monoclonal antibodies IC2 and A2B5 was studied. IC2 is a rat-rat hybridoma autoantibody produced from the BB rat; among islet cells, IC2 is beta-cell specific. A2B5 is an anti-ganglioside antibody described as labeling beta-cells. Islets of Langerhans from Lewis rats were isolated and cultured for 18 h in RPMI-1640 with five different glucose concentrations (2.2, 3.3, 5.5, 11.1, and 18.3 mM). In some experiments, islets were precultured for 2 or 3 days. After isolation of islet cells and antibody labeling, the percent of IC2+ beta-cells in the different groups increased from 33.3, 34.5, 40.9, and 57.2 to 58.6% (P less than 10(-6). For A2B5, the percent of labeled islet cells increased from 37.4, 41.8, 46.7, and 53.8 to 56.2% (P less than 10(-4). Thus, increasing glucose concentration leading to higher beta-cell activity implies an increase in antigen expression. Neither A2B5 nor IC2 reacts with insulin, as shown by absorption experiments and immune electron microscopy of binding sites. Electron microscopy of IC2-gold-labeled islet cells substantiated the beta-cell specificity of IC2. In conclusion, expression of the corresponding antigens to IC2 and A2B5 depends on the functional state of the beta-cells; because this has been shown to be an important factor in the development of insulin-dependent diabetes, our findings may be of potential pathogenetic interest.
对与抗胰岛细胞表面单克隆抗体IC2和A2B5相对应的抗原表达进行了研究。IC2是一种由BB大鼠产生的大鼠-大鼠杂交瘤自身抗体；在胰岛细胞中，IC2对β细胞具有特异性。A2B5是一种抗神经节苷脂抗体，被描述为可标记β细胞。从Lewis大鼠分离出胰岛，并在含有五种不同葡萄糖浓度（2.2、3.3、5.5、11.1和18.3 mM）的RPMI-1640中培养18小时。在一些实验中，胰岛先预培养2或3天。分离胰岛细胞并进行抗体标记后，不同组中IC2 + β细胞的百分比从33.3%、34.5%、40.9%和57.2%增加到58.6%（P小于10^(-6)）。对于A2B5，标记的胰岛细胞百分比从37.4%、41.8%、46.7%和53.8%增加到56.2%（P小于10^(-4)）。因此，葡萄糖浓度升高导致β细胞活性增强意味着抗原表达增加。吸收实验和结合位点的免疫电子显微镜检查表明，A2B5和IC2均不与胰岛素反应。IC2金标记胰岛细胞的电子显微镜检查证实了IC2对β细胞的特异性。总之，与IC2和A2B5相对应的抗原表达取决于β细胞的功能状态；由于这已被证明是胰岛素依赖型糖尿病发生发展的一个重要因素，我们的发现可能具有潜在的致病学意义。
