{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,18]],"date-time":"2026-10-18T23:03:43Z","timestamp":1792364623344,"version":"4.4.0"},"update-to":[{"DOI":"10.1371\/journal.pntd.0010619","type":"new_version","label":"New version","source":"publisher","updated":{"date-parts":[[2022,7,21]],"date-time":"2022-07-21T00:00:00Z","timestamp":1658361600000}}],"reference-count":46,"publisher":"Public Library of Science (PLoS)","issue":"7","license":[{"start":{"date-parts":[[2022,7,11]],"date-time":"2022-07-11T00:00:00Z","timestamp":1657497600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Health and Medical Research Council (NHMRC) of Australia","award":["APP1160046"],"award-info":[{"award-number":["APP1160046"]}]},{"name":"National Health and Medical Research Council (NHMRC) of Australia","award":["APP2008433"],"award-info":[{"award-number":["APP2008433"]}]},{"name":"National Health and Medical Research Council (NHMRC) of Australia","award":["APP1098244"],"award-info":[{"award-number":["APP1098244"]}]},{"name":"National Health and Medical Research Council (NHMRC) of Australia","award":["APP1102926"],"award-info":[{"award-number":["APP1102926"]}]},{"name":"National Health and Medical Research Council (NHMRC) of Australia","award":["APP1037304"],"award-info":[{"award-number":["APP1037304"]}]}],"content-domain":{"domain":["www.plosntds.org"],"crossmark-restriction":false},"short-container-title":["PLoS Negl Trop Dis"],"abstract":"<jats:sec id=\"sec001\"><jats:title>Background<\/jats:title><jats:p><jats:italic>Schistosoma japonicum<\/jats:italic>is one of three major species of blood flukes causing schistosomiasis, a disease, which continues to be a major public health issue in the Philippines. SjSAP4, a member of a multigene family of saposin-like proteins, is a recognized immunodiagnostic biomarker for schistosomiasis japonica. This study aimed to identify linear B-cell epitopes on SjSAP4 and to validate their potential as components of a multi-epitope assay for the serological diagnosis of schistosomiasis japonica.<\/jats:p><\/jats:sec><jats:sec id=\"sec002\"><jats:title>Methodology<\/jats:title><jats:p>SjSAP4-derived peptides were expressed as GST-peptide-fused proteins and these were Western blot probed with human serum samples from<jats:italic>S<\/jats:italic>.<jats:italic>japonicum<\/jats:italic>Kato-Katz (KK)-positive individuals and uninfected controls. A core epitope was further identified by Western blotting through probing a series of truncated peptides with the schistosomiasis patient sera. The diagnostic performance of the core epitope-containing peptides and the full-length SjSAP4 was evaluated by enzyme-linked immunosorbent assay (ELISA) using a panel of sera collected from subjects resident in a schistosomiasis-endemic area of the Philippines.<\/jats:p><\/jats:sec><jats:sec id=\"sec003\"><jats:title>Main findings<\/jats:title><jats:p>As a result of the peptide mapping, one peptide (P15) was found to be highly immunogenic in the KK-positive individuals. We subsequently showed that -S<jats:sup>163<\/jats:sup>QCSLVGDIFVDKYLD<jats:sup>178<\/jats:sup>- is a core B-cell epitope of P15. Subsequent ELISAs incorporating SjSAP4, SjSAP4-Peptide and SjSP-13V2-Peptide showed a sensitivity of 94.0%, 46.0% and 74.0%, respectively, and a specificity of 97.1%, 100% and 100%, respectively. Notably, complementary recognition of the B-cell epitopes (SjSAP4-Peptide and SjSP-13V2-Peptide) was observed in a subset of the KK-positive individuals. A dual epitope-ELISA (SjSAP4-Peptide + SjSP-13V2-Peptide-ELISA) showed a diagnostic sensitivity of 84.0% and a specificity of 100%.<\/jats:p><\/jats:sec><jats:sec id=\"sec004\"><jats:title>Conclusions\/Significance<\/jats:title><jats:p>In this study, -S<jats:sup>163<\/jats:sup>QCSLVGDIFVDKYLD<jats:sup>178<\/jats:sup>- was identified as a dominant linear B-cell epitope on SjSAP4. This peptide and the complementary recognition of other B-cell epitopes using sera from different KK-positive individuals can provide the basis of developing a multi-epitope assay for the serological diagnosis of schistosomiasis.<\/jats:p><\/jats:sec>","DOI":"10.1371\/journal.pntd.0010619","type":"journal-article","created":{"date-parts":[[2022,7,11]],"date-time":"2022-07-11T17:33:58Z","timestamp":1657560838000},"page":"e0010619","update-policy":"https:\/\/doi.org\/10.1371\/journal.pntd.corrections_policy","source":"Crossref","is-referenced-by-count":17,"title":["Identification of a linear B-cell epitope on the Schistosoma japonicum saposin protein, SjSAP4: Potential as a component of a multi-epitope diagnostic assay"],"prefix":"10.1371","volume":"16","author":[{"given":"Yi","family":"Mu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Catherine 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