title: Biochemical and immunochemical characterisation of a 20-kilodalton complex of surface-associated antigens from adult Onchocerca gutturosa filarial nematodes.
abstract: Surface radioiodination of adult Onchocerca parasites reveals a restricted range of proteins associated with the cuticle. We present data to show that prominent among these is a complex of low-molecular-weight proteins which can be released in soluble form by homogenisation of surface-labelled Onchocerca gutturosa in phosphate-buffered saline (PBS). One of this groups of proteins, designated gp20, has a molecular mass of 20,000, is glycosylated with two N-linked carbohydrate side chains, and has a basic pI. Other PBS-soluble, 125I-labelled proteins of similar size appear not to be glycosylated. A distinct group of molecules are released only in the presence of reducing agents, and are likely to be cuticular collagens. The low-molecular-weight components are antigenic and cross-reactive with Onchocerca volvulus infection sera. Cross-reactions are also observed in immunoprecipitation experiments using sera from Brugia-immunised animals and infected humans. Comparative two-dimensional analyses of these immunoprecipitates reveal at least two Onchocerca specific components. As an alternative to radiolabelling and PBS homogenisation, incubation of worms in medium containing the reducing agent 2-mercaptoethanol resulted in a similar set of molecules being released into the medium. Since surface antigens of O. gutturosa from bovines and O. volvulus from humans appear similar in size and are antigenically cross-reactive, the more readily available parasite is being used to study further the properties of these molecules and to provide reagents for raising antisera reactive to the equivalent O. volvulus antigens.
authors.affiliation: Department of Pure and Applied Biology, Imperial College of Science, Technology and Medicine, London, U.K.
authors.forename: J E
authors.initials: JE
authors.lastname: Bradley
authors.forename: W F
authors.initials: WF
authors.lastname: Gregory
authors.forename: A E
authors.initials: AE
authors.lastname: Bianco
authors.forename: R M
authors.initials: RM
authors.lastname: Maizels
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology*; D000947:Antigens, Helminth / Q000032:analysis* / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D002846:Chromatography, Affinity; D003429:Cross Reactions; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D008297:Male; D009854:Onchocerca / Q000276:immunology*; D009855:Onchocerciasis / Q000175:diagnosis* / Q000276:immunology; D011233:Precipitin Tests
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D000954:Antigens, Surface; D007106:Immune Sera