title: Development of a monoclonal antibody for use in radioimmunoassay of ethynylestradiol.
abstract: Production of monoclonal antibodies (MABs) to a 17 alpha-ethynyl-1,3,5 (10)-estratriene-3,17 beta-diol (ethynylestradiol, EE2) hapten is described. Culture antibodies generated by hybridized cells tested in enzyme-linked immunosorbent assay (ELISA) bound the 6-oxoethynyl-estradiol-6-(0-carboxymethyl) oxime-bovine serum albumin conjugate (EE2-6-0 CMO-BSA) but not BSA. On radioimmunoassay (RIA) with tritiated ethynylestradiol (3H-EE2), some of the antibodies demonstrated high binding affinity (Ka = 2.8 X 10(10) M-1) to EE2. Estradiol-17 beta, estrone and estriol did not show any displacement of 3H-EE2 from the MABs even at high concentration (1 X 10(4) ng/mL). Among the widely used progestins, norethynodrel and norethisterone exhibited considerable cross-reactivity (25.7-100% and 0.3-54.1%, respectively) but not levonor-gestrel with the MABs. The high affinity demonstrated by the MABs to EE2 3-sulfate but not to EE2 17-sulfate and EE2 3,17-disulfate suggests the dominant role of the 17 beta-hydroxyl group in immunogenicity.
mesh_terms: D000911:Antibodies, Monoclonal / Q000096:biosynthesis*; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000032:analysis*; D004997:Ethinyl Estradiol / Q000032:analysis* / Q000276:immunology; D012739:Gonadal Steroid Hormones; D005779:Immunodiffusion; D011863:Radioimmunoassay
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D012739:Gonadal Steroid Hormones; D004997:Ethinyl Estradiol