Investigations of the antigenic differences between the EG95-G1 vaccine and related protein from the G6 genotype of Echinococcus granulosus (#86)
The EG95 vaccine is based on a recombinant protein which native antigen is encoded by four genes in the G1 genotype of E. granulosus. The EG95 vaccine has been successfully used under experimental conditions raising protective immune response in intermediate hosts against the challenge with E. granulosus from the same G1 genotype. No information is available about the ability of the current EG95 vaccine to elicit a protective immune response against other genotypes of E. granulosus. Using genomic DNA cloning techniques, seven eg95–related genes were characterised from the G6 genotype of E. granulosus. Three proteins are predicted to be encoded by these genes. Investigations were undertaken to determine the ability of two of these proteins to react with specific antibodies in the sera of sheep vaccinated with EG95 and shown to be protected against a challenge infection with the G1 genotype. Proteins from the G6 genotype displayed only limited antigenic cross-reactivity with the current EG95 vaccine antigen, suggesting that the current vaccine may not protect animals against an infection with parasites of the G6 genotype. Data presented provides the information that would enable a G6 genotype-specific vaccine to be developed against E. granulosus.