title: Surface membrane proteins of Biomphalaria glabrata embryonic cells bind fucosyl determinants on the tegumental surface of Schistosoma mansoni primary sporocysts.
abstract: Previous observations that in vitro adherence of Biomphalaria glabrata embryonic (Bge) cells to sporocyst larval stages of Schistosoma mansoni was strongly inhibited by fucoidan, a sulfated polymer of L-fucose, suggested a role for lectinlike Bge cell receptors in sporocyst binding interactions. In the present investigation, monoclonal antibodies with specificities to 3 major glycan determinants found on schistosomes, LacdiNAc, fucosylated LacdiNAc (LDNF), and the Lewis X antigen, were used in adhesion blocking studies to further analyze the molecular interactions at the host-parasite interface. Results showed that only the anti-LDNF antibody significantly reduced snail Bge cell adhesion to the surface of sporocysts, suggesting that fucosyl determinants may be important in larval-host cell interactions. Affinity chromatographic separation of fucosyl-reactive Bge cell proteins from fucoidan-bound Sepharose 4B revealed the presence of polypeptides ranging from 6 to 200 kDa after elution with fucoidan-containing buffer. Pre-elution of the Bge protein-bound affinity column with dextran (Dex) and dextran sulfate (DexS) before introduction of the fucoidan buffer served as controls for protein binding based on nonspecific sugar or negative charge interactions. A subset of polypeptides (approximately 35-150 kDa) released by fucoidan elution was identified as Bge surface membrane proteins, representing putative fucosyl-binding proteins. Far-western blot analysis also demonstrated binding reactivity between Bge cell and sporocyst tegumental proteins. The finding that several of these parasite-binding Bge cell proteins were also fucoidan-reactive suggests the possible involvement of these molecules in mediating cellular interactions with sporocyst tegumental carbohydrates. It is concluded that Bge cells have surface protein(s) that may be playing a role in facilitating host cell adhesion to the surface of schistosome primary sporocysts through larval fucosylated glycoconjugates.
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2115 Observatory Drive, Madison, Wisconsin, USA.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Castillo
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Wu
authors.forename: Nathalie
authors.initials: N
authors.lastname: Dinguirard
authors.forename: A Kwame
authors.initials: AK
authors.lastname: Nyame
authors.forename: Richard D
authors.initials: RD
authors.lastname: Cummings
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Yoshino
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000918:Antibody Specificity; D001700:Biomphalaria / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D015153:Blotting, Western; D002448:Cell Adhesion / Q000276:immunology; D002460:Cell Line; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D005643:Fucose / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D033661:Oocysts / Q000737:chemistry / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012550:Schistosoma mansoni / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D008565:Membrane Proteins; D011134:Polysaccharides; D011956:Receptors, Cell Surface; D005643:Fucose; C007789:fucoidan