FROM ALLERGY TO SCHISTOSOMES - ROLE OF FC-RECEPTORS AND ADHESION MOLECULES IN EOSINOPHIL EFFECTOR FUNCTION

The dual function of eosinophils has been evidenced in protective immu nity against parasites as well as in pathological manifestations durin g allergic disorders. We have demonstrated that a new class of IgE rec eptors, Fc epsilon RII/CD23, was involved in the functional duality of eosinophils and other proinflammatory cells. More recently, we have s hown that Fc epsilon RI, the high affinity IgE receptor thought to be only expressed by basophils and mast cells, was involved in eosinophil -mediated cytotoxicity against schistosomes as well as in mediator rel ease. These results favour the view that both IgE and its receptors ha ve been primarily associated to a protective immune response rather th an to pathology. Not only IgE receptors but also members belonging to the family of adhesion molecules can participate as co-receptors in eo sinophil effector-function. The inhibitory role of monoclonal antibodi es to Lewis(X) (Le(X) CD15) or to selectins in eosinophil-mediated cyt otoxicity towards schistosomes and the detection of Le(X) and 'selecti n-like' molecules on schistosomula surface indicate a double interacti on mediated by selectins and their carbohydrate ligands between eosino phils and schistosomula. These results suggest new functions for these adhesion molecules, previously known to be involved mainly in cell in filtration.