Isolation and partial characterization of a surface glycoconjugate of Entamoeba histolytica.
To study surface molecules of Entamoeba histolytica we produced monoclonal antibodies from mice immunized with lysates from the pathogenic amebic strain HM1:IMSS, and screened them for the ability to inhibit E. histolytica adhesion. One monoclonal antibody, CC 8.6, was a potent inhibitor of amebic adhesion to a Chinese hamster ovary cell line, and was capable of inhibiting HM1:IMSS mediated cytotoxicity by 50%. We found that monoclonal antibody CC 8.6 bound to an amebic glycoconjugate. The glycoconjugate is present only in E. histolytica and not in other Entamoeba sp. It migrates as a polydisperse band on SDS-PAGE, and can be metabolically radiolabeled with [14C]glucose, [32P]phosphate, and [3H]palmitate. The glycoconjugate can be purified by hydrophobic interaction chromatography on octyl-Sepharose; enzymatic hydrolysis with phosphatidylinositol-specific phospholipase C alters the hydrophobic properties of the molecule. HPLC analysis of [14C]glucose-labeled glycoconjugate saccharides revealed that approximately 82% of the incorporated label was in glucose and 12% in galactose. Our studies demonstrate that one of the immunogenic surface molecules of E. histolytica is a phosphorylated, lipid-containing, glycoconjugate, and that antibodies to this antigen may have the potential to protect against E. histolytica adhesion and cytotoxicity.
Stanley
S L
SL
Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110.
Huizenga
H
H
Li
E
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D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000302:isolation & purification; D000953:Antigens, Protozoan / Q000276:immunology* / Q000302:isolation & purification; D000954:Antigens, Surface / Q000276:immunology* / Q000302:isolation & purification; D015153:Blotting, Western; D002448:Cell Adhesion; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004748:Entamoeba histolytica / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006001:Glycoconjugates / Q000276:immunology* / Q000302:isolation & purification; D051379:Mice; D010766:Phosphorylation; D011402:Pronase / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D006001:Glycoconjugates; D011402:Pronase