title: Echinococcus granulosus: variability of the host-protective EG95 vaccine antigen in G6 and G7 genotypic variants.
abstract: Cystic hydatid disease in humans is caused by the zoonotic parasite Echinococcus granulosus. As an aid to control transmission of the parasite, a vaccine has been produced for prevention of infection in the parasite's natural animal intermediate hosts. The vaccine utilizes the recombinant oncosphere protein, EG95. An investigation into the genetic variability of EG95 was undertaken in this study to assess potential antigenic variability in E. granulosus with respect to this host-protective protein. Gene-specific PCR conditions were first established to preferentially amplify the EG95 vaccine-encoding gene (designated eg95-1) from the E. granulosus genome that also contains several other EG95-related genes. The optimized PCR conditions were used to amplify eg95-1 from several parasite isolates in order to determine the protein-coding sequence of the gene. An identical eg95-1 gene was amplified from parasites showing a G1 or G2 genotype of E. granulosus. However, from isolates having a G6 or G7 genotype, a gene was amplified which had substantial nucleotide substitutions (encoding amino acid substitutions) compared with the eg95 gene family members. The amino acid substitutions of EG95 in the G6/G7 genotypes may affect the antigenicity/efficacy of the EG95 recombinant antigen against parasites of these genotypes. These findings indicate that characterization of eg95 gene family members in other strains/isolates of E. granulosus may provide valuable information about the potential for the EG95 hydatid vaccine to be effective against E. granulosus strains other than the G1 genotype.
authors.affiliation: University of Melbourne, Veterinary Clinical Centre, Princes Highway, Werribee, Vic. 3030, Australia.
authors.forename: Conan
authors.initials: C
authors.lastname: Chow
authors.affiliation: University of Melbourne, Veterinary Clinical Centre, Princes Highway, Werribee, Vic. 3030, Australia.
authors.forename: Charles G
authors.initials: CG
authors.lastname: Gauci
authors.affiliation: Veterinary Control and Research Institute, Pendik 81480, İstanbul, Turkey.
authors.forename: Gulay
authors.initials: G
authors.lastname: Vural
authors.affiliation: Hydatid Epidemiology and Control Program, 12 Mildura Street, Fyshwick, ACT 2609, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Jenkins
authors.affiliation: Wallaceville Animal Research Centre, AgResearch, Upper Hutt, New Zealand.
authors.forename: David D
authors.initials: DD
authors.lastname: Heath
authors.affiliation: Departamento de Parasitología, Instituto Nacional de Enfermedades Infecciosas, ANLIS "Dr. Carlos G. Malbrán" Av. Velez Sarsfield 563, Buenos Aires (1281), Argentina.
authors.forename: Mara C
authors.initials: MC
authors.lastname: Rosenzvit
authors.affiliation: Department of Parasitology, School of Medicine, Kerman University of Medical Sciences, Kerman, P.O. Box 444, Iran.
authors.forename: Majid Fasihi
authors.initials: MF
authors.lastname: Harandi
authors.affiliation: University of Melbourne, Veterinary Clinical Centre, Princes Highway, Werribee, Vic. 3030, Australia.
authors.forename: Marshall W
authors.initials: MW
authors.lastname: Lightowlers
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D015139:Blotting, Southern; D018509:DNA, Helminth / Q000737:chemistry; D004285:Dogs; D004443:Echinococcosis / Q000469:parasitology* / Q000517:prevention & control; D048209:Echinococcus granulosus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D014644:Genetic Variation; D005838:Genotype; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D016133:Polymerase Chain Reaction; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology / Q000517:prevention & control / Q000635:transmission; D013552:Swine; D014614:Vaccines, Synthetic / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D015047:Zoonoses / Q000635:transmission
chemical_list: D000947:Antigens, Helminth; D018509:DNA, Helminth; C446034:EG95 protein, Echinococcus granulosus; D015801:Helminth Proteins; D014614:Vaccines, Synthetic