Fluoroimmunoassay for the determination of allergen using bacterial magnetic particles

We have developed a novel fluoroimmunoassay method using bacterial magnetic particles for the determination of allergen. Fluorescein isothiocyanate (FITC) conjugated IgE antibody was immobilized onto bacterial magnetic particles. The decrease of fluorescence intensity by aggregation of FITC-labeled bacterial magnetic particle conjugates was determined by a fluorescence spectrophotometer. The relative fluorescence intensity decreased with increasing allergen concentration. A linear relationship was obtained between the relative fluorescence intensity and allergen concentration in the range of 0.1 100 ng/ml. This method may be carried out across a wider concentration range having a linear response than when artificial magnetite particles are used.