Basophil histamine release induced by anti-IgE and concanavalin A. Relation to the total plasma IgE content.

The plant lectin concanavalin A (Con A) has been shown to induce basophil histamine release by an IgE-receptor-dependent process resembling that of anti-IgE-antibodies. In this study, the concentration-response for basophil histamine release from washed blood cells was analyzed in a population of blood samples from adults with a total plasma IgE content ranging from < 5 kU/l to > 18,000 kU/l (n = 108), as well as 148 cord blood samples. The concentration-response-curves for anti-IgE in all adult blood samples were similar, despite the large variation in total plasma IgE--only the cord blood samples showed a decreased sensitivity. In contrast, the optimal concentration of Con A was inversely related to plasma IgE, and this relation was most pronounced in the adult blood samples. It is proposed that IgE-receptor-mediated histamine release may be dependent not only on the number of stimulatory, dimeric cross-links formed between IgE-receptors, but also on the molecular structure of the cross-linking agent.