SOMATIC ANTIGENS OF ADULT DICROCOELIUM-DENDRITICUM RECOGNIZED BY BILEANTIBODIES OF NATURALLY INFECTED CATTLE

Bile samples, from slaughtered cattle harbouring between 120 and 280 a dult lancet flukes, were used to investigate the range of somatic prot eins inducing local antibody responses in naturally infected animals. Lancet fluke infections induced local (bile) antibody responses agains t Tris-buffered saline (TBS) soluble, sodium dodecyl sulphate (SDS) so luble and 2-mercaptoethanol (2-Me) soluble somatic proteins of adult D icrocoelium dendriticum. IgA antibody isotypes predominated in the res ponse against buffer-soluble somatic antigens, whereas SDS-soluble and 2-Me-soluble proteins induced similar level of both IgA and IgG1 anti bodies. Analysis of the antigens recognised by particular isotype-spec ific bile antibodies suggests that different antigens preferentially i nduce isotype restricted antibody responses. The bile antibody respons e was highly species specific, only one antigen from somatic protein e xtracts of Fasciola hepatica being precipitated by bile samples showin g the highest reactivity against D. dendriticum.