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.