Monoclonal antibodies against human IgE. Identification of an epitope sharing properties with the high-affinity receptor binding site.

Abstract Three monoclonal antibodies to human IgE are described. One of them recognizes an epitope located within a region of 76 amino acids that has been shown to contain the fc ϵ RI binding site. That epitope is shown to be susceptible to heating and to alkylation of cysteines involved in inter heavy chain bonds, but not to their reduction alone. In addition, this monoclonal antibody, although having a high affinity for free IgE, is unable to bind Fc ϵ RI-linked IgE. Based on these results, we discuss the possibility that the antibody recognizes the fc ϵ RI binding site of the IgE molecule.