Human eosinophils express a receptor for secretory component. Role in secretory IgA-dependent activation.

摘要: The existence of a functional receptor for secretory component (SC) on the eosinophil membrane might explain preferential degranulation induced by IgA (sIgA) when compared to serum IgA. Indeed, flow cytometry analysis revealed that purified human SC could bind subpopulation (4-59%) blood eosinophils from 19 patients with eosinophilia. Binding radiolabeled be competitively inhibited using unlabeled or but not IgG. Immunoprecipitation and immunosorbent chromatography presence major at 15 kDa in extracts as well culture supernatants neutrophils. 15-kDa protein eluted was able sIgA Eosinophils preincubated released cationic (ECP) peroxidase (EPO) after addition anti-SC anti-IgA monoclonal antibody respective cross-linking reagents. These results indicated binding free complexed induce degranulation. Furthermore, dose-dependent inhibition mediator release IgA, suggested involved mediated sIgA. indicate novel pathway activation its potential involvement mucosal immunity, particularly inflammatory diseases associated infiltration enhanced production