Induction of protective immunity against murine secondary hydatidosis.

Significant protective immunity against secondary hydatidosis in mice was achieved by immunization with a preparation of surface molecules of E. granulosus protoscoleces with Freund's incomplete adjuvant (PSEx-IFA). Study of PSEx-IFA immunogenicity demonstrates that glucidic epitopes evoked mainly IgM responses while peptidic epitopes evoke mainly IgG responses; however both types of epitopes elicit both types of responses. Analysis of the possible association between susceptibility or resistance to infection and antibody responses after challenge was also performed. Cyst fluid antigen (CFAg) specific antibody titres on month eight after challenge correlated with number and size of cysts. On the other hand no correlation was observed between protection and PSEx specific IgG titres either on the day of challenge or one month later. Nonetheless, immunoblot analysis revealed that some PSEx molecules were recognized on day 30 after challenge only by sera from immunized mice.