USE AND LIMITATION OF LABELED STAPHYLOCOCCAL PROTEIN A FOR STUDY OF ANTINEUTROPHIL ANTIBODIES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 54  (6) , 1330-1337
Abstract
Antineutrophil antibodies could be detected following their attachment to [human] neutrophils by employing labeled staphylococcal protein A (SPA). Radiolabeled SPA provided a sensitive means for identifying the presence of Ig[immunoglobulin]G restricted to subclasses IgG1, IgG2 and IgG4 that would specifically bind to neutrophils and that were found in the serum of patients with isoimmune and autoimmune neutropenia. SPA bound to the Fc region of IgG did not interfere with the attachment of IgG to the Fc domain of the neutrophil. Fluorescein-labeled SPA, in turn, was useful in monitoring the functional consequences of antibody attachment to the surface of polymorphonuclear leukocytes (PMN). Heterologous and isoimmune antisera induced lateral movement of surface antigens into polar-capped pseudopodia. The formation of such pseudopodia may facilitate leukoagglutination and the subsequent removal of sensitized cells from the circulation.