Differences in binding affinity of human IgE for receptors in chopped human lung

Experiments were performed to ascertain whether IgE in different allergic sera had the same or different sensitizing properties for chopped human lung. When allergic sera were allowed to compete with myeloma IgE for tissue receptors in chopped lung and subsequently challenged with antigen, two groups of sera could be distinguished, one which competed well with myeloma IgE and one which competed poorly. Sera that competed well with myeloma IgE were also able to sensitize for greater histamine release relative to IgE concentration when sensitized lung tissue was challenged with anti-IgE. The converse was true of those sera that competed poorly with myeloma IgE in the antigen assay, in that they sensitized for histamine release only at relatively high IgE concentrations in the anti-IgE assay. The possible significance of these findings is discussed.