title: Methyl-beta-Cyclodextrin treatment and filipin staining reveal the role of cholesterol in surface membrane antigen sequestration of Schistosoma mansoni and S. haematobium lung-stage larvae.
abstract: Ex vivo lung-stage larvae of Schistosoma mansoni and S. haematobium do not bind specific antibodies in the indirect membrane immunofluorescence test (IF), probably as a result of confinement of the surface membrane antigens in immobile, lipid-rich sites. Treatment with the membrane-impermeable, cholesterol-extracting drug methyl-beta-cyclodextrin (MBCD) and staining with filipin III (filipin), a fluorescent polyene antibiotic widely used for the detection and quantitation of cholesterol in biomembranes, allowed us to examine the role of cholesterol in surface membrane antigen sequestration of S. mansoni and S. haematobium ex vivo lung-stage larvae. Treatment of S. mansoni larvae with MBCD elicited appreciable cholesterol depletion as judged by filipin-cholesterol fluorescence diminution, which was accompanied by a considerable increase in specific antibody binding in IF, thus suggesting that cholesterol plays a predominant role in sequestration of the surface membrane antigens of S. mansoni lung-stage schistosomula. Despite that, MBCD induced an almost complete depletion of cholesterol from the outer membrane of S. haematobium larvae; no increase in specific antibody binding in IF was evident, implying that cholesterol is not responsible for masking surface membrane antigens of S. haematobium lung-stage larvae.
authors.affiliation: Zoology Department, Faculty of Science, Cairo University, Cairo 12613, Egypt.
authors.forename: Hatem
authors.initials: H
authors.lastname: Tallima
authors.forename: Rashika
authors.initials: R
authors.lastname: El Ridi
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000378:metabolism*; D000954:Antigens, Surface / Q000378:metabolism; D002784:Cholesterol / Q000502:physiology*; D006224:Cricetinae; D005372:Filipin / Q000737:chemistry*; D005455:Fluorescent Antibody Technique; D007814:Larva / Q000187:drug effects / Q000276:immunology; D008168:Lung / Q000469:parasitology; D008297:Male; D008647:Mesocricetus; D051379:Mice; D008810:Mice, Inbred C57BL; D008860:Microscopy, Ultraviolet; D012548:Schistosoma haematobium / Q000187:drug effects / Q000276:immunology*; D012550:Schistosoma mansoni / Q000187:drug effects / Q000276:immunology*; D013194:Staining and Labeling; D047392:beta-Cyclodextrins / Q000494:pharmacology*
chemical_list: D000947:Antigens, Helminth; D000954:Antigens, Surface; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D005372:Filipin; D002784:Cholesterol