Receptor for IgG(Fc) and human β₂-microglobulin on S. mansoni schistosomula

Abstract

HOST antigen uptake by schistosomes is generally considered from circumstantial evidence to be a potent mechanism by which schistosomes can evade immune response and has therefore stimulated several investigations on the chemical nature of the molecules as well as their possible mode of incorporation¹. These studies have indicated that the parasite can acquire host material in the form of glycolipids of erythrocyte origin² and gene products of the murine major histocompatibility complex³. As an alternative to host antigen incorporation, the possibility of immunological blockade has been suggested. Host immunoglobulins have been demonstrated to be associated with the tegumental surfaces of Schistosoma mansoni from mice and baboons, and recent experiments^4,5 have shown the presence of heterospecific antibody on the tegumental surface of S. mansoni adult worms. The ability of adsorbed antibodies to bind their respective antigens indicates that some of these immunoglobulins are orientated so as to present at least one free Fab region of the antibody molecule. Although this could merely represent a nonspecific adsorption, it could also represent the specific binding of the immunoglobulin on the parasite's surface. Using a rosette test we have now demonstrated the presence of receptors for both IgG(Fc) and human β₂-microglobulin.