Identification of a laminated layer-associated protein in Echinococcus multilocularis metacestodes
Echinococcus multilocularis is a cestode parasite that predominantly infects red and arctic foxes as definitive hosts. Ingestion of E. multilocularis eggs and subsequent post-oncospheral infection with the larval stage (metacestode) of the parasite results in alveolar echinococcosis (AE), a life-threatening hepatic disease concerning humans and other intermediate hosts such as small rodents. The primary fluid-filled vesicles of the asexually proliferating metacestode are comprised of an inner germinal layer, a syncytial tegument, and an outer, acellular, so-called laminated layer. This laminated layer may play an important role in protecting the developing E. multilocularis metacestode from host immune reactions, and laminated layer-associated components represent potential targets for intervention during the course of AE. We have used an in vitro cultivation technique for the long-term maintenance and proliferation of E. multilocularis metacestodes in order to generate premature (protoscolex-free) parasite vesicles. A polyclonal antiserum was raised against this host-free parasite tissue. Subsequent immunoblot analysis of parasite fractions obtained by Triton X-114 extraction led to the identification of a 116 kDa protein (named EmP2) within the Triton-insoluble fraction. The characterization of EmP2 by SDS–PAGE, Western blotting, and by immunofluorescence revealed that EmP2 is a laminated layer-associated protein.(Received July 23 1997)
(Revised September 18 1997)
(Revised November 19 1997)
(Accepted November 19 1997)
Key Words: Echinococcus multilocularis; laminated layer; host–parasite interaction.
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