Use of polymeric materials as a solid phase for radioimmunoassay and immunoradiometric assay techniques

Poly(acrylamide-acrylic acid-acrylonitrile)-ferrous sulfate, p(AM-AA-AN)-FeSO₄·7H₂O, resin was used as a solid phase for estimation of thyroid stimulating hormone (TSH) by radioimmunoassay (RIA) and immunoradiometric assay (IRMA) techniques. Comparison with cellulose particles as a known polymer solid phase was made. The tracers for RIA and IRMA were prepared by radioiodination of TSH antigen and TSH monoclonal antibody, respectively, using Iodogen as oxidizing agent. The tracers were purified by gel chromatography on Sephadex G-25 column. The polyclonal anti-TSH antibody was prepared via immunization of three white New Zealand rabbits with highly purified TSH antigen. The polymer was prepared by addition of aqueous solution of comonomer (AA-AN) and FeSO₄ as cross-linker to polyacrylamide p(AM) and irradiation of the mixture at ambient temperature in a ⁶⁰Co γ-cell. The polymer prepared and cellulose particles were activated using 1,1-carbonyldiimidazole, and these activated particles were coupled with the polyclonal TSH antibody. Optimization and validation of the RIA and IRMA techniques were made.