Reactions of sera from immunised and experimentally infected thick-lipped grey mullet,Chelon labrosus(Risso, 1826), with isolated proteins ofCryptocotyle lingua(Creplin, 1825)

The reactions of sera from thick-lipped grey mullet,Chelon labrosus(Risso, 1826), experimentally infected with metacercariae of the digeneanCryptocotyle lingua(Creplin, 1825) were compared with those from mullet and rabbits immunised with sonicated cercariae using Western blotting. SDS-PAGE revealed 35 proteins from the redia and cercaria respectively and 20 from the metacercaria ofC. lingua. Antisera from rabbits reacted most strongly and with the greatest number of proteins. Common antigens exist between all three stages of the life cycle. Cross-reactivity was also detected betweenC. linguaand the first intermediate molluscan host,Littorina littorea. The failure of sera from fish exposed to metacercarial infection to react with some parasite proteins may suggest a role for the metacercarial cyst wall in evasion of the host response.