Development of an immunochemical method for determination of human kepsinogen isozynogens and its clinical application

1. 克隆并分析了人胃蛋白酶原A基因。结果表明，至少存在三个不同的基因，其中至少有两个基因在人类染色体dna上倾向于对齐。克隆了大鼠丙氨酸蛋白酶原C基因，并对其外显子的碱基序列和特征进行了分析。克隆了人胃蛋白酶原C基因，并确定了其所有显子的碱基序列及其邻近区域。4. 采用Southern-blot方法对92名日本人血细胞DNA的限制性核酸酶差异进行了分析，结果表明日本人存在3种不同的胃蛋白酶原A基因。研究了人、猴和猪胃蛋白酶原A的活化机制。结果表明，其作用机制在不同物种间存在显著差异，人胃蛋白酶原同工酶原间的作用机制也存在显著差异。建立了人胃蛋白酶原A （of I）的酶联免疫吸附试验（ELISA），采用抗该酶原的杂杂瘤单克隆抗体。正常人血清胃蛋白酶原A浓度范围为15 ~ 100 ug/1。与对照组相比，活动性十二指肠溃疡或胃溃疡患者血清胃蛋白酶原水平明显较高，而胃癌患者血清胃蛋白酶原水平明显较低。这项试验被认为是有用的筛选工作，以确定受试者在增加风险的十二指肠和胃溃疡的胃癌采用刚果红法内镜下测定胃蛋白酶原A （PGA）和胃蛋白酶原C （PGC）水平及PGA/PGC比值。PGA值和PGA/PGA比值在慢性胃炎和胃癌的检测中有重要意义。

1. Human pepsinogen A genes were clones and analyzed. The results showed that there exist at least three different genes and that at least two of them are tendemly aligend on a human chromosomal DNA.2. Rat prpsinogen C gens was cloned and the base sequences of all the exons and their veicnities were elucidated.3. Human pepsinogen C gene was cloned and the base suquences of all the xons and their vicinities were elucidated. 4. Restrriction nuclease difests of human blood cell DNA from 92 Japanese subjects were analyzed by Southern-blot analysis, demonstrating the presence of three different pepsinogen A genes in Japanese.5. The activation mechamisms of human, monkey and pocine pepsinogens A were investigated. The results showed that the mechanism differs significantly among species and that among human pepsinogen isozymogens the mechanism also differs significantly.6. An enzyme-linked immunsorbent assay (ELISA) for human pepsinogen A (of I) was developed by using a hybridoma monoclonal antibody against the zymogen. The concentration range of serum pepsinogen A in gealthy controls was 15-100 ug/1. Serum pepsinogen Levels were significantly higher in the subjects who developed active duodenal ulcer or active gastric ulcer, but significantly lower in those who had gastric cance, than in control subjects. This assay is thought to be useful in the screening work to identify subjects at incrteased tisk for gastric cancer of duodenal and gastric ulce.7 The serum level of pepsinogen A (PGA) and pepsinogen C (PGC) and the PGA/PGC ratio were compared with the surface area of the fundic mucosa, as determined endoscopically by the Congo red method. The PGA velue as well as the PGA/PGA ratio were shown to be useful in detection of chronic gastritis and gastric cancer.