Immunoaffinity Purification of Prostaglandin E 2 and Leukotriene C 4 Prior to Radioimmunoassay: Application to Human Synovial Fluid

Abstract

When human synovial fluid as such was subjected to radioimmunoassays of prostaglandin E₂ (PGE₂) and leukotriene C₄ (LTC₄), there was no linear increase in PGE₂ and LTC₄ as the amount of synovial fluid was raised. For removal of substances thus disturbing the assay we developed a method of immunoaffinity purification of PGE₂ and LTC₄. A monoclonal antibody against PGE₂ or LTC₄ was coupled to BrCN-activated Sepharose 4B. When synovial fluid mixed with radiolabelled PGE₂ or LTC₄ was applied to the column of immobilized antibody, the ligand was adsorbed to the column and eluted with a mixture of methanol/water in a recovery of about 80%. The purified material showed a linearity between the amount of the sample and the value of radioimmunoassay. The one-step method was applied to synovial fluid from patients with rheumatoid arthritis, osteoarthritis and other joint diseases.