MOPC 104E IgM/anti-idiotype solid-phase inhibition assay as a model for screening myeloma proteins for ligand binding specificity

Protection against the staphylococcal enterotoxin-induced intestinal disorder in the monkey by anti-idiotypic antibodies

The staphylococcal enterotoxin serotype B (SEB)-induced enteric intoxication and the immediate-type reaction in the skin of unsensitized monkeys was used to define whether agents competing with SEB for target cell receptors may inhibit pathophysiological effects. For this purpose a duodenal provocation test was developed by use of a pediatric gastroscope, allowing the evaluation of the influence of antagonists on the intestinal disorder upon SEB challenge at the same duodenal site. First, carboxymethylation of histidine residues of SEB caused a complete loss of emetic and skin-sensitizing activity without changing the immunological specificity. However, carboxymethylated SEB is a strong inhibitor of enteric intoxications and immediate-type skin reactions upon SEB challenge. Second, after immunization of BALB/c mice with monoclonal anti-SEB antibodies, monoclonal antiidiotypic antibodies (anti-Id) were obtained by the "hybridoma technique" and purification by idiotype-affinity chromatography. Anti-Id specifically inhibited the binding of horseradish peroxidase-labeled anti-SEB to the ligand, and SEB blocked as well the interaction of these two antibody species, indicating a high degree of binding-site selectivity. Anti-Id completely protected against emetic response and diarrhea upon duodenal provocation with SEB and inhibited immediate-type skin reactions as well. Further, anti-Id acted as an antagonist without triggering biologic functions themselves. This shows that anti-Id constitute a useful tool to protect against a bacterial toxin-induced intestinal disorder.

Anti-idiotypic antibodies that inhibit immediate-type skin reactions in unsensitized monkeys on challenge with staphylococcal enterotoxin

The staphylococcal enterotoxin B (SEB)-induced immediate-type skin reaction in unsensitized monkeys was used as a nonimmunological mast cell stimulus to examine whether the toxin exerts its effect via specific receptors on the target cell membrane. Anti-idiotypic antibodies (anti-Id) were raised in BALB/c mice against monoclonal anti-SEB antibodies (anti-SEB) and purified by idiotype affinity chromatography. The anti-Id nature of the antibody was demonstrated by its ability to inhibit the binding of 125I-labeled anti-SEB to the ligand in a concentration-dependent manner. Moreover, binding of anti-SEB to anti-Id was antagonized by the SEB ligand in a competitive way. These antibodies completely abolished skin reactions in unsensitized monkeys on challenge with SEB and impeded those provoked by staphylococcal enterotoxins A and C1 but did not have the biological activity of the toxin. These data are compatible with the view that receptors for staphylococcal enterotoxins may exist on the membrane of mast cells in the skin of unsensitized monkeys. The data suggest an experimental approach for producing anti-cell receptor antibodies that are of potential value to influence the course of staphylococcal enterotoxin-mediated effects.