Selective Regulation of Eosinophil Degranulation by Interleukin 1β

Recent evidence confirms that cytokines such as IL-1, IL-4, IL-5, and GM-CSF may enhance or inhibit eosinophil function. Functions that are susceptible to modulation include eosinophil-mediated antibody-dependent damage of helminthic parasites, oxidative metabolism and degranulation. We have employed IgG and IgE-coated Sepharose beads to investigate selective modulation of IgG and IgE-mediated enzyme release by IL-1β. Both IgG and IgE-coated beads induced release of granular enzymes β-glucuronidase and arylsulfatase. Enzyme release from IgG-stimulated eosinophils was inhibited by preincubation with IL-1β (100 pg/ml, P ≤ 0.05). In contrast, enzyme release by IgE-stimulated eosinophils was enhanced by IL-1β (100 pg/ml, P ≤ 0.05). These studies support the hypothesis that IL-1β has specific selective actions on eosinophil function. Furthermore, these actions on particle-stimulated enzyme release suggest that IgG and IgE mediated processes in eosinophils are differentially regulated.