抗血吸虫药物—硝硫氰胺的放射免疫测定

本文报告了抗血吸虫药硝硫氰胺(7505)的放射免疫测定法。以7505与卵清白蛋白或猪IgG结合作抗原以免疫家兔;¹³¹I标记BSA-7505作标记抗原;并采用聚乙二醇(PEG)为分离剂。测定范围为0.64～400 ng,重复性良好。PEG的分离效果与双抗体法一致。4只家兔经一次胃饲7505(120 mg/kg体重)后,各兔血中7505浓度的变化趋势基本一致。给药后第2～3天时血中7505浓度达高峰,结果与胃饲³H-7505测定³H放射性的类似。同时并对14种7505的衍化物作了放射免疫交叉反应试验,试图探索其与结构及实验性疗效的关系。结果表明,交叉反应出现于具有基本结构的各化合物,倘改变两苯环间的则与7505的抗血清无交叉反应。交叉反应与药效的初筛结果不同,后者当两苯环间的改为-O-并不受到影响。根据交叉反应的结构特征,7505抗血清同样可应用于若干7505衍化物的定量测定。

RADIOIMMUNOASSAY FOR AN ANTISCHISTOSOMAL DRUG, 4-NITRO-4''-ISOTHIOCYANO-DIPHENYLAMINE (7505)

A radioimmunoassay methed for an anti-schistosomal drug, 4-nitro-4'-isothiocyano-diphenylamine, is described.The antigen used for immunizing rabbits was prepared by coupling 7505 with ovalbumin or porcine IgG. ~(131)I was used for the preparation of labelled antigen, polyethylene glycol (PEG)being used as a separating agent.This assay comprises a range of about 0.64-400 ng 7505 per test. The reproducibility was shown to be satisfactory. The results obtained from PEG separation was close to those from double antibody method.After giving 7505 (120 mg/kg body wt.) per os to four rabbits, the blood concentration of 7505 varies in a similar pattern. The levels rose to a peak value about 2～3 days after drug administration. The results obtained were the same as those by the method using ³H-7505. A series of 14 analogs of 7505 have been tested by RIA for cross reactions, and the relationships between the degree of cross reactions and Validity of experimental treatments were discussed.It is concluded that cross reactions existed in those compounds comprising the structure of NO₂ R. If the—group between the two benzene rings was modified, the cross reactions vanished. 7505 antisera may also be used in the quantitative determination for some of the anlogs of 7505 tested.