Eosinophil interaction with antibody-coated, non-phagocytosable surfaces: Changes in cell surface proteins

Open Access
Publisher Website
Google Scholar
Abstract
Plasma membrane changes during the interaction of human eosinophils with large, antibody-coated, non-phagocytosable surfaces have been investigated in a model system. Human peripheral blood eosinophils were incubated with layers of agar into which tetanus toxoid and human anti-tetanus immunoglobulin, together with an eosinophil chemotactic factor (EOF), were incorporated. Changes in organization of the eosinophil plasma membrane proteins during interaction with the agar layer were detected by lactoperoxidase-catalysed iodination with [125]iodide. A protein of apparent mol. wt 55000 became newly accessible on the eosinophil surface as a specific consequence of interaction with antigen-antibody complexes in the agar layer. This protein appeared in the early attachment phase of the interaction which preceded extracellular degranulation. Cytochalasin D enhanced its appearance, while Mg2+-deficiency prevented it. A second newly accessible protein of apparent mol. wt 58000 was blocked when ECF was present and may therefore be a receptor for ECF. Other proteins of apparent mol. wt 68000 and 46000 newly appeared at the surface of eosinophils even after incubation in suspension, apparently as a consequence of the rapid cycling of membrane components which occurs in eosinophils.