IgE Measurement in Serum and Culture Supernatant

It has been known for more than 20 years that the immunoglobulin E (IgE) molecules are responsible for anaphylactic reactions (Ishizaka, 1985), and for about 10 years that their synthesis is regulated in an isotype-specific fashion. Indeed, various factors have been found in mice and rats which control the synthesis and secretion of IgE by B lymphocytes. Factors such as IgE binding factors (Ishizaka, 1984), IgE T suppressor factors (Kishimoto, 1982) and the suppressor factor of allergy (Katz, 1984) have now been identified. Similar mechanisms seem to regulate IgE production in human beings (Gavériaux et al., 1988). For instance, human T-T hybridoma producing IgE binding factors (Ishazaka et al., 1985) or secreting biologically active suppressor factor of allergy (Katz, 1985) were recently constructed, and human T cell hybridoma lines were also derived from patients with the hyper IgE syndrome (Leung and Geha, 1985); supernatants from these hybridomas were shown to modulate IgE production by B cells and, as in the rat or mouse models, the biological activity of the factors was determined by their level and/or specificity of glycosylation (Gavériaux et al., 1988). Most of the mechanisms underlying the IgE isotype specific regulation have not yet been unravelled, principally because of the difficulty in detecting specifically this minor isotype of immunoglobulin, where the concentration in the serum is in the order of µg per ml of serum, in the presence of other serum immunoglobulin isotypes which are present in mg/ml concentrations, thus of a one-thousand higher order of magnitude.