Protein sequences of Echinococcus multilocularis and E. granulosus were retrieved from NCBI Entrez Protein Database on October 16, 2007 . NCBI Entrez Protein Database are compiled from a variety of sources with daily updates, including SwissProt, PIR, PRF, PDB, and translations from annotated coding regions in GenBank and RefSeq. To identify putative membrane or extracellular proteins, the protein sequences were analyzed using TMHMM II [18] for prediction of transmembrane domains, GPI-SOM [19] for prediction of glycosylphosphatidylinisotol (GPI) anchor signals, and PSORT II [17] for prediction of protein subcellular localization. All protein sequences were further screened for stretches of alpha-helical coiled-coils using Paircoil2 [21] and intrinsically unstructured regions using IUPred [20] . Both of these structures are believed to adopt native conformation in aqueous solution and therefore constitute major selection criteria. Due to the limited number of Echinococcus sequences in NCBI Entrez Protein Database and few predicted surface proteins containing stretches of alpha-helical CC and/or IURs, the analysis was extended to all proteins with alpha-helical coiled-coil and IUR predictions, irrespective of their predicted locations. This included known proteins previously tested in immunodiagnosis. To narrow down protein regions for selection of 30mer peptides, protein sequences were subjected to prediction of coiled-coil stability by STABLECOIL (http://biomol.uchsc.edu/cores/biophysics/ stablecoil). In case of IURs antigenicity predictions were performed using BepiPred [28] . Thus detected regions of high predicted CC stability or antigenicity were favored. To increase solubility, peptides were selected to start and end with a hydrophilic or neutral amino acid and to harbour on average one charged amino acid, either positive or negative, per five residues. In addition, the guidelines suggested by the manufacturer were followed (http://www.altabioscience.bham.ac.uk/ pdfs/Intro_to_series_SYNTHETIC_PEPTIDES.pdf). From 11 sequences listed in table S1, 45 peptides were selected according to the criteria mentioned above.