A recombinant immunodiagnostic antigen for bovine cysticercosis.

The 70% ammonium sulfate-soluble fraction of the cyst fluid of Taenia hydatigena (designated ThFAS) was previously shown to have potential as an immunodiagnostic reagent for bovine cysticercosis. Western blot analysis indicated that the specific reactivity with antibodies in sera of T. saginata-infected cattle was associated with a 10 kDa component. Rabbit antiserum to ThFAS identified a homologous antigenic protein from the cestode Taenia crassiceps. Consequently, a cDNA expression library was constructed in lambda gt11 using poly A mRNA purified from T. crassiceps metacestodes and screened with rabbit antiserum to ThFAS. One strongly reactive clone (designated lambda TCA-2) produced a 123 kDa beta-galactosidase fusion protein which reacted in Western blot with sera from calves experimentally-infected with T. saginata and did not react with sera from uninfected calves or from cattle infected with Fasciola hepatica or with common gastrointestinal cattle parasites.

Application of biotechnology methods to the study of cestodes.

The advent of biotechnology has invigorated research on the control of cestode diseases, especially cysticercosis infections in man and animals. The utilization of hybridoma technology to produce antigen-specific monoclonal antibodies has resulted in great strides towards obtaining pure antigens relevant for immunodiagnostic purposes and for research on vaccines. However, the isolation and identification of antigens is only the initial step in the development of such reagents. Production of antigens in quantities sufficient for research/development and commercialization is hampered by the scarcity of viable parasite material for extraction. Expectations are that this problem can be surmounted by application of recombinant DNA methods to produce cloned genes for antigen expression in cultured microorganisms or cells. Remarkable progress has been made recently in isolating and cloning genes from several important cestode species and antigens have been expressed in vitro with genes cloned from Taenia taeniaformis and T. hydatigena. Although these early efforts have not as yet resulted in practical antigen production, the prospects for doing so appear good. The complex epidemiology of cestode diseases is another research subject that has benefited from the successful application of the tools of biotechnology. For example, the greater precision in typing biological variants afforded by DNA analysis has led to important revisions of the understanding of hydatid disease. DNA probes are now available for Echinococcus spp, which are effective for typing isolates. These probes may also find use as reagents for distinguishing eggs of Echinococcus from other taeniid eggs, a serious difficulty for field investigations.(ABSTRACT TRUNCATED AT 250 WORDS)