Recognition of the galactose- or N-acetylgalactosamine-binding lectin of Entamoeba histolytica by human immune sera.
Cure of amebic liver abscess is associated with resistance to recurrent invasive amebiasis and the development of a humoral and cell-mediated immune response. We determined whether human immune sera contain blocking antibody for the 170-kilodalton (kDa) galactose or N-acetylgalactosamine (Gal/GalNAc)-binding lectin of Entamoeba histolytica. By Western blot (immunoblot) of whole amebae subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, all eight immune sera studied here prominently recognized a 170-kDa amebic protein. Western blot of the purified Gal/GalNAc lectin with pooled human immune sera (PHIS) confirmed that the 170-kDa band was the adherence lectin. Immunoprecipitation of [35S]methionine-metabolically-labeled amebae with the antilectin monoclonal antibody H8-5 and with PHIS demonstrated that the 170-kDa lectin was the major antigen recognized by PHIS. The in vitro adherence of E. histolytica trophozoites to CHO cells at 4 degrees C was inhibited by prior exposure of amebae to greater than or equal to 1.0% PHIS. The humoral response to the Gal/GalNAc-binding lectin of the parasite may contribute to the development of protective immunity against invasive amebiasis.
D000268:Adhesiveness; D000818:Animals; D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan / Q000032:analysis*; D000953:Antigens, Protozoan / Q000276:immunology; D015295:Antigens, Tumor-Associated, Carbohydrate; D001345:Autoradiography; D001667:Binding, Competitive; D002846:Chromatography, Affinity; D004187:Disaccharides / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D004748:Entamoeba histolytica / Q000276:immunology*; D006801:Humans; D007106:Immune Sera / Q000032:analysis / Q000276:immunology; D007118:Immunoassay; D037102:Lectins / Q000276:immunology*; D008101:Liver Abscess, Amebic / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015295:Antigens, Tumor-Associated, Carbohydrate; D004187:Disaccharides; D007106:Immune Sera; D037102:Lectins; C016467:Thomsen-Friedenreich antigen