Analysis of islet antoantigens by the screening of a mouse islet cDNA expression library.

通过用糖尿病前期NOD小鼠血清免疫筛选NOD小鼠胰岛β细胞dagt 11表达文库，获得两个克隆。克隆（C17和C18）被NOD小鼠血清识别，但不被Balb/c小鼠血清识别。在10周龄雌性NOD小鼠血清中分别检测到80%和10%的C17和C18融合蛋白抗体。C18的DNA序列与小鼠嗜铬粒蛋白A cDNA（596-1892）相同。C17的核苷酸序列显示一个poly（A）尾和46个氨基酸的开放阅读框架。北方印迹法检测胰腺和脑组织中C17 mRNA的表达。在人胰腺cDNA中发现了一段与C17高度同源的核苷酸序列，将其克隆到质粒载体中进行分析。通过放射免疫测定，使用体外转录和翻译的[^<35>S]-甲硫氨酸标记的小鼠嗜铬粒蛋白A作为抗原，测量嗜铬粒蛋白A的抗体。在糖尿病前期雌性NOD小鼠中，抗嗜铬粒蛋白A的流行率约为10%。然而，C17抗体放射性测定不足以灵敏地测量循环抗体的滴度。我们还用体外转录和翻译的[^ S]-甲硫氨酸标记的ICA 512测量了人类受试者中的ICA 512（IA-2）抗体<35>。ICA 512抗体在急性起病的IDDM患者中的频率高于缓慢进展的IDDM患者，ICA 512 AA的频率和滴度在起病后5年内均急剧下降，提示ICA 512 AA抗体与急性β细胞破坏有关。

Two clones were obtained by immunoscreening of an NOD mouse islet lambdagt11 expression library with prediabetic NOD mouse sera. The clones (C17 and C18) were recognized by NOD mouse sera but not by Balb/c mouse sera. Antibodies against C17 and C18 fusion proteins were detected in 80% and 10% of sera from 10 week-old female NOD mice, respectively. DNA sequences of C18 were identical to mouse chromogranin A cDNA (596-1892). Nucleotide sequences of C17 showed a poly (A) tail and open reading frame for 46 amino acids. C17 mRNA was detected by the Northern blot analysis in the pancreas and brain tissue. A nucleotide sequence with high homology with C17 was found in human pancreas cDNA.The sequence was cloned in a plasmid vector for further analysis. Antibodies to chromogranin A were measured by radioimmunoassays using as antigens in vitro transcribed and translated [^<35>S]-methionine-labeled mouse chromogranin A.The prevalence of anti-chromogranin A was approximately 10% in prediabetic female NOD mice. Whereas, the C17 antibody radioassay was not sensitive enough to measure titers of circulating antibodies. We also measured ICA512 (IA-2) antibodies in human subjects with the in vitro transcribed and translated [^<35>S]-methionine-labeled ICA512. The frequency of the ICA512 antibodies was higher in acute-onset IDDM than slowly progressive IDDM.The frequency and titer of ICA512AA declined sharply within 5 years after the onset of IDDM,suggesting the association of the antibody and acute beta-cell destruction.