Inhibition of idiotype-anti-idiotype reaction in particle counting immunoassay as a tentative assay of IgE

Rabbit antibodies were raised against a purified mouse monoclonal IgG1 antibody having specificity for the D epsilon 2 determinant of human IgE. After appropriate absorption this antiserum was anti-idiotype specific and was used to set up a particle counting immunoassay for human IgE. Latex particles coated with F(ab')2 fragments of the anti-idiotypic antibodies were agglutinated by the monoclonal anti-IgE antibody (20 ng/ml). This reaction was inhibited up to 100% by human IgE and the assay took 30 min to perform with a sensitivity of 40 IU/ml. The coefficient of correlation with a routine IgE assay was r = 0.96, and the mean analytical recovery tested on 10 sera was 95.8%.