Abstract
By using agar gel diffusion reaction with antiserum against extracts from adult flukes of Fasciola sp., the nature of potential antigens was compared among the extracts from adult flukes, larvae of different ages (14 and 35 days old) and metacercariae of the parasite. Two precipitating line, "a" and "b", were observed between antiserum and each of extracts from adult and larval flukes of different ages. A precipitating line was observed with extracts from metacercariae. It was fused with line "a" obtained with the extracts from adult flukes and the antiserum. A similar experiment was carried out with the serum of a rabbit exposed to metacercariae. When the serum was allowed to react with extracts from adult and larval flukes of different ages, two precipitating lines appeared. One of these lines was fused with line "b" described above and the other was line "c" which was neither line "a" or "b". Two precipitating lines were also observed between the extracts from metacercariae and the same serum. One of these lines was line "d" detected only in metacercariae and the other was minor component differing from line "d" (line "e"). The indirect immunofluorescent antibody test was carried out to demonstrate the distribution of antigens in precipitating lines observed between Fasciola infected rabbit serum and extracts. The result indicated that antigen "b" in precipitating line "b" was distributed mainly in the gut cecum of the larval flukes and antigen "d" in the metacercariae. From the results of this investigation, it was suggested that antigen "c" might distribute in the cuticle and immediately subjacent cellular layer of the larval fluke and antigen "e" in the metacercarial outercyst.
