Neutrophil Chemotaxis and Superoxide Production Are Induced by Cross-linking FcγRII Receptors

Neutrophils express two types of receptor for the Fc region of IgG, FcγRII and FcγRIIIB. Via these receptors, neutrophils bind IgG complexes that contain more than one IgG molecule. This binding activates functional processes, such as the respiratory burst and chemotaxis. Neutrophils were treated with biotinylated anti-Fc receptor monoclonal antibodies and chemotaxis toward streptavidin, a cross-linking agent, was determined. Cross-linking FcγRII and not FcγRIIIB induced neutrophil chemotaxis. Superoxide production in response to immobilized anti-Fc receptor antibodies was also examined. Anti-FcγRII Fab bound to ELISA plates induced superoxide production, while anti-FcγRIIIB Fab did not. Pretreatment of neutrophils with anti-FcγRII Fab reduced superoxide generated by immobilized anti-FcγRII antibody. The data demonstrate that FcγRII and not FcγRIIIB are responsible for neutrophil chemotaxis and superoxide production upon Fc receptor activation.