DEMONSTRATION OF IGG-FC-RECEPTORS AND C3-RECEPTORS ON ADULT SCHISTOSOMA-MANSONI

  • 1 January 1981
    • journal article
    • research article
    • Vol. 126  (1) , 379-384
Abstract
Previous studies have indicated that adult schistosomes have an affinity for both IgG and C [complement], thorough investigations on the possible presence of receptors for these serum proteins on the adult schistosome tegument have not been attempted. The present study presents evidence for both IgG-Fc and C3 receptors on adult schistosomes. An indirect assay utilizing fluoresceinated Staphylococcus aureus was developed to detect antigen-antibody (Ag-Ab) and antigen-antibody-C (Ag-Ab-C) binding to adult parasites [from mice]. Detection of Ag-Ab and Ag-Ab-C complex binding was dependent on the presence of a metabolic inhibitor in the incubation mixture, presumably to prevent shedding of bound complexes. Ag-Ab complex binding required the presence of an intact Fc on the IgG of the complex and could be partially inhibited by preincuabtion of parasites in heataggregated IgG or an isolated Fc preparation. Binding of Ag-Ab-C complexes was dependent on active C3 in the C source but not on an intact Fc on the IgG of the complex. Ag-Ab-C binding could be blocked by prior incubation of parasites in heat-aggregated IgG-C but not by C alone. Binding of host serum proteins to IgG-Fc and C3 receptors on adult schistosomes may aid parasite survival by helping to prevent immune detection.