Production, characterization and clinical application of antisera to cortisol

In the present paper the production of highly specific and sensitive antisera to cortisol is described. The antisera were generated in rabbits using both cortisol-3-monooxime and cortisol-3,20-dioxime derivatives. Bovine thyroglobulin was used as a carrier protein. Antibody characteristics were determined by radioimmunoassay procedure. Antibody titers observed after immunization with the monooxime conjugate were significantly higher (p less than 0.001) than those obtained with the dioxime conjugate. In addition, cross reactivity for various naturally occurring steroids was markedly lower and sensitivity was increased as compared to dioxime antisera (15 vs. 40-60 pg/tube). Accuracy and precision were calculated for the monooxime antiserum used in a RIA system for clinical application. A close correlation (r = 0,9802) was found between plasma cortisol values measured by radioimmunoassay and the competitive protein binding method. The concentrations obtained by the protein binding method were slightly but significantly higher than those measured by radioimmunoassay indicating higher specificity of the antibody used (p less than 0.005).