FURTHER CHARACTERIZATION OF THE 38 KDA ANTIGEN FROM ECHINOCOCCUS-GRANULOSUS (HYDATID-DISEASE) CYST FLUID - EVIDENCE FOR ANTIGENIC HETEROGENEITY AND REACTIVITY WITH ANTI-P1 ANTIBODIES

A panel of 5 IgM and 6 IgG1 monoclonal antibodies (MoAbs) was produced against a band, eluted from a reducing SDS-PA GE gel, containing the 38 kDa subunit of antigen 5 (Ag5) front Echinococcus granulosus cyst f luid; seven of the MoAbs were shown subsequently to bind epitopes on A g 5 but none recognized phosphorylcholine or periodate-sensitive carbo hydrate epitopes. Differences in the fine speciJicit2' of the MoAbs rt ere apparent and, upon reduction, heterogeneity in 38 kDa components from hydatid cyst fluids of different intermediate host origin was rev ealed by peptide fingerprinting and immunoblotting using the MoAbs. On e of the IgG1 MoAbs (ED9) was able to distinguish a reduced 38 kDa mol ecule in cyst fluids fi om two distinct genotypes-the horse/dog and sh eep/dog strains-of E. granulosus and this may, have implications for h ydatid serology, immunoepidemiology and strain typing. Furthermore, ep itopes on this 38 kDa component or on a different molecule with the sa me or similar M(r) are reactive with anti-P1 blood group antigen antib odies and this could result in false-positive reactions where sera fro m P2 patients with suspected hydatid disease are tested by immunoblot or immunoprecipitation analysis.