1983 年 103 巻 10 号 p. 1054-1059
In order to obtain specific antisera used for enzyme immunoassay of dexamethasone, dexamethasone-21-hemisuccinate (I), dexamethasone-6-carboxymethyl thioether (II) and dexamethasone-3-(O-carboxymethyl) oxime (III) were synthesized. Each compound was coupled with bovine serum albumin (BSA) by mixed anhydride method or carbodiimide method, and the complex was immunized in rabbit. As a labelled compound, alkaline phosphatase was conjugated with I, II and III using water-soluble carbodiimide. Bound and free dexamethasones were separated by the double antibody method. The specificity of each antiserum was assessed by determining cross-reactivity of other corticoids by means of enzyme immunoassay. Anti-II-BSA and anti-III-BSA antisera had higher specificity than that of anti-I-BSA antisera. Anti-II-BSA and anti-III-BSA antisera were purified by the method of affinity chromatography packed with betamethasone-3-(O-carboxymethyl) oxime-, II-, and III-Sepharose 4B, respectively. Percent cross-reactivities against betamethasone, a C-16 epimer of dexamethasone, of purified anti-II-BSA and anti-III-BSA antisera decreased remarkably. Using these purified antisera, it was possible to determine the amount of 0.2-20ng per assay tube of dexamethasone, in the presence of 100-fold betamethasone.