Science and Technology Production

Variability of the host-protective EG95 vaccine antigen in G6 and G7 genotypic variants

Article

Authorship:

CHOW C ; GAUCI CG ; VURAL G ; JENKINS DJ ; HEATH DD ; ROSENZVIT, MARA CECILIA ; HARANDI MF ; COWMAN AF ; LIGHTOWLERS MW

Date:

2008

Publishing House and Editing Place:

Academic Press

Magazine:

EXPERIMENTAL PARASITOLOGY, vol. 119 (pp. 499-505) Academic Press

Summary *

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 antigenic variability in E. granulosus. 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 characterisation 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. Information provided by the agent in SIGEVA