CARBOHYDRATES ON THE SURFACE OF ECHINOCOCCUS-GRANULOSUS PROTOSCOLECESARE IMMUNODOMINANT IN MICE

A carbohydrate enriched soluble fraction (CHP) was prepared by mild tr eatment of viable Echinococcus granulosus protoscoleces (PSC) with the enzyme endoglycosidase-F (endo-F) and characterized by SDS-PAGE, glyc osidae-inhibition ELISA, and immunoblotting. Three groups of four BALB /c mice were immunized with the CHP, with the remaining deglycosylated PSC (DGP) and with dead PSC (DPSC) to analyse the relative immunogeni city of carbohydrates on the surface of PSC. A fourth sentinel group w as not immunized. The antibody response was analyzed during primary an d hyperimmune responses. Specific antibody titres (IgG and IgM) agains t somatic PSC antigens (PSA) were evaluated by ELISA and their antigen recognition pattern by immunoblotting, discriminating carbohydrate an d peptide specific antibody responses by periodate treatment of PSA. T he avidity index of those antibodies and the titer of non-specific imm unoglobulins during the whole protocol were evaluated by ELISA. In vit ro mitogenic activity of CHP was also evaluated. The results indicated : 1) immunodominance of surface carbohydrate epitopes from PSC, 2) pre dominant IgM and low avidity response against these epitopes, 3) a dra matic increase of non-specific antibody titres and 4) in vitro mitogen ic activity of CHP.