biostudies-literatureUnknown4Kronenberg PAAlveolar echinococcosis (AE) caused by <i>Echinococcus multilocularis</i>, is a severe zoonotic disease in humans. One of the major metacestode antigens of <i>E. multilocularis</i> is the Em2 or Em2(G11) native purified antigen. The Em2 antigen is used for the serological and histopathological diagnosis of AE in humans and plays an important role in parasite-host interactions. As the Em2(G11) antigen is a mucin-type and glycosylated protein, the protein backbone has not been identified yet. We have targeted the protein backbone identification through mass spectrometry (LC-MS/MS) analysis of the Em2(G11) antigen. As a result, we evidenced that the Em2(G11) antigen consists of 33 unique protein candidates of which the most abundant was ''EmuJ_001105600.1''. This protein (889 amino acids) hadFrontiers in parasitology1540215https://www.ebi.ac.uk/biostudies/studies/S-EPMC11935348biostudies-literatureIdentification and characterization of the elusive protein backbone of the immuno-dominant and species-specific Em2(G11) metacestode antigen of <i>Echinococcus multilocularis</i>.PMC11935348Reinehr MKronenberg PADeibel AEichenberger RMDeplazes PLaurimae THasler SGehrig PWeber AfalseIdentification and characterization of the elusive protein backbone of the immuno-dominant and species-specific Em2(G11) metacestode antigen of <i>Echinococcus multilocularis</i>.Alveolar echinococcosis (AE) caused by <i>Echinococcus multilocularis</i>, is a severe zoonotic disease in humans. One of the major metacestode antigens of <i>E. multilocularis</i> is the Em2 or Em2(G11) native purified antigen. The Em2 antigen is used for the serological and histopathological diagnosis of AE in humans and plays an important role in parasite-host interactions. As the Em2(G11) antigen is a mucin-type and glycosylated protein, the protein backbone has not been identified yet. We have targeted the protein backbone identification through mass spectrometry (LC-MS/MS) analysis of the Em2(G11) antigen. As a result, we evidenced that the Em2(G11) antigen consists of 33 unique protein candidates of which the most abundant was ''EmuJ_001105600.1''. This protein (889 amino acids) had2025-01-01T00:00:00Z20252026-07-15T05:39:46.003Z2025-07-02T03:04:36.967ZS-EPMC119353484013507310.3389/fpara.2025.1540215