Immunoprecipitation of in vitro translation products of Fasciola hepatica RNA.

Incubation of in vitro translation products of RNA isolated from Fasciola hepatica with immune rat serum and sera from infected sheep resulted in the immunoprecipitation of a number of polypeptides, most of which had similar electrophoretic mobilities. Although only one of these (a 30 kDa species) correlated precisely in mobility with that of biosynthetically labelled excretory-secretory (ES) antigens, this polypeptide (along with several others) was also immunoprecipitated by sheep sera raised against authentic ES antigens. This verified that the isolated RNA contained mRNA species encoding ES antigens of the parasite. In addition, immune rat serum immunoprecipitated a 64 kDa polypeptide which was not immunoprecipitated by infected sheep serum or anti-ES antigen sheep serum. The possible significance of this finding in terms of the ability of rats to develop resistance to fascioliasis in contrast to sheep which apparently cannot is discussed.