Evidence that a protective membrane epitope is involved in early but not late phase immunity in Schistosoma mansoni.
An anti-egg monoclonal antibody E.1, which is partially protective in passive transfer experiments, is shown in this study to recognize a membrane epitope on cercariae, schistosomula, and the ciliary plates of miracidia. E.1 did not bind to the surface membranes of lung or adult worms, or recognize secreted egg antigen in infected liver tissue. The E.1 epitope was present in the glycocalyx of cercariae, as well as on the syncytial membrane as determined by electron microscopy. Immunoprecipitation of iodinated surfaces of cercariae and schistosomula demonstrated E.1 binding to a high m.w. moiety in cercariae, which corresponds to the glycocalyx because it was not immunoprecipitated from schistosomula. In addition, a band at 38,000 daltons was immunoprecipitated from both cercariae and schistosomula. When compared with in vitro cultured parasites, schistosomula that were obtained from mice 1 to 24 hr after tail vein injection showed significant loss of E.1 binding. Consistent with the rapid loss of antigen in vivo, E.1 antibody was unable to passively transfer protection to naive mice when administered 5 days after cercarial challenge.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000947:Antigens, Helminth / Q000276:immunology*; D002462:Cell Membrane / Q000276:immunology; D000939:Epitopes; D005455:Fluorescent Antibody Technique; D007814:Larva / Q000276:immunology; D008099:Liver / Q000469:parasitology; D008970:Molecular Weight; D010063:Ovum / Q000276:immunology; D012550:Schistosoma mansoni / Q000276:immunology*; D012555:Schistosomiasis mansoni / Q000276:immunology*; D013997:Time Factors
D000911:Antibodies, Monoclonal; D000947:Antigens, Helminth; D000939:Epitopes