title: Characterization of proteinases in different isolates of adult Haemonchus contortus.
abstract: A high degree of intra- and inter-geographical variation has been demonstrated previously in the excretory/secretory proteinases released by adult Haemonchus contortus. Proteinase activity has also been associated with host-protective 'hidden' antigens isolated from the gut of adult H. contortus. If similar geographical strain variation also exists within the gut-associated proteinases, this will have important implications for the development of a globally effective vaccine. The proteinases active in integral-membrane protein extracts from 3 different strains of adult H. contortus were characterized on the basis of their pH optima and molecular size. Although enzyme activity was detected over a wide pH range, the majority of proteinase activity was detected at acidic pH. Differences in specific activity and size of enzymes were observed between the 3 different parasite strains at different pH values. A high degree of conservation in reactive peptides was observed when protein extracts were probed with antisera raised to the protective hidden gut-antigen complexes isolated from the Moredun strain of H. contortus, or to bacterially expressed subcomponents thereof. Therefore, despite the observed differences in membrane-bound proteinase profiles, the similarity of the immunogenic response against these hidden antigens may be sufficient to prove protective against different geographical isolates of H. contortus.
authors.affiliation: Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, Scotland, UK. redmd@mri.sari.ac.uk
authors.forename: D L
authors.initials: DL
authors.lastname: Redmond
authors.forename: R
authors.initials: R
authors.lastname: Windham
mesh_terms: D000818:Animals; D000940:Antigenic Variation; D000947:Antigens, Helminth / Q000378:metabolism; D002364:Caseins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006188:Haemonchiasis / Q000276:immunology / Q000469:parasitology* / Q000517:prevention & control; D006189:Haemonchus / Q000201:enzymology* / Q000276:immunology / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D008565:Membrane Proteins / Q000378:metabolism; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism*
chemical_list: D000947:Antigens, Helminth; D002364:Caseins; D008565:Membrane Proteins; C026018:azocasein; D010447:Peptide Hydrolases