[Development of a Soviet immunoenzyme test system for the quantitative determination of human immunoglobulin E]

An EIA system for the quantitative determination of human IgE was developed. As the solid phase, polystyrene microplates sensitized with the gamma globulin fraction of sheep antiserum to human IgE were used in this system. Peroxidase conjugate with IgE was prepared with the use of periodate technique. The optimum parameters for the sorption of antibodies on polystyrene were determined: protein concentration, the pH of the buffer, temperature, the time of fixation, the working dilution of the conjugate. As the substrate of peroxidase activity, ortho-phenilenediamine solution with hydrogen peroxide was used. The result was evaluated by means of a photometer, model Titertek Multiskan MC (Flow Laboratories Ltd., Great Britain), at the wavelength 429 nm. The new EIA system proved to be specific and detected IgE in the sera under investigation at a concentration of 10(-9) g/ml. The system permitted the determination of the normal level of IgE in a group of healthy adults, this level being, on the average, 76 +/- 9 kU/1.