新单克隆抗体荧光诊断法的建立及在胃癌诊断中的应用

作者取含鼠抗人胃癌单克隆抗体(单抗)MG小鼠腹水,经DEAE-52离子交换层析后,获得纯化的单抗(IgG),与溴化氰活化的Sepharose 4B偶联制备免疫吸附剂,取免疫吸附剂分别与检测的血清或腹水混合反应后,用标记荧光的单抗MG识别。根据免疫亲和层析的原理,解离荧光抗体并用荧光分光光度计检测荧光强度,分别以良性病组相对荧光强度的均数加2个标准差之和(血清组(?)+2S=2.8AU,腹水组(?)±2S=3.7AU)作为判断肿瘤阳性的阈值。结果:胃癌患者血清MG-Ag检出阳性率为61.1％(22/36),腹水为75.0％(18/24);而良性患者血清假阳性率为7.7％(2/26),腹水为6.7％(2/30)。实验结果证实MG-Ag的检测对胃癌的诊断具有一定价值,本方法是一种准确而灵敏的新方法。

Establishment and Application of Immunofluorescence Using monoclonal Antibodies in Diagnosis of Gastric Cancer

Monoclonal antibodies (MG) against gastric cancer were purified through a DEAF-52 column and coupled with CNBr-activated sepharose 4B. The MG - sepharose 4B was then incubated with the scrum and ascites of patients with gastric cancer and benign diseases for 2 hours. After being blocked by scrum of a normal mouse, the MG-sepharose 4B was made to react with the MG- labeled with fluorescein isothio-cyanate for 30 min. By means of immunoaffinity chromatography, the MG labeled with fluorescein isothio - cyanate was isolated from MG-sepharose 4B with separating solution and then detected by fluorospectrometer. The amount of fluorescence represened the amount of the MG- Ag in the separating solution. The mean values plus 2 standard deviations of the benign diseases group were arbitrarily set as thar positive threshold respcctively.The positive rate was 61.1% (22/36) in sera and 75% (18/24) in ascites of patients with gastric cancer. It is suggested that the determination of MGAg in the serum and ascites of patients may be useful for the diagnosis of gastric cancer.