{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:50:21Z","timestamp":1760233821069,"version":"build-2065373602"},"reference-count":12,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,2,23]],"date-time":"2021-02-23T00:00:00Z","timestamp":1614038400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100009619","name":"Japan Agency for Medical Research and Development","doi-asserted-by":"publisher","award":["JP20wm0325011","JP20fk0108270","JP20fk010826"],"award-info":[{"award-number":["JP20wm0325011","JP20fk0108270","JP20fk010826"]}],"id":[{"id":"10.13039\/100009619","id-type":"DOI","asserted-by":"publisher"}]},{"name":"the Research Funds of the President of Osaka General Medical Center","award":["none"],"award-info":[{"award-number":["none"]}]},{"name":"the Joint Usage\/Research Center Program on inFront, Kyoto University","award":["none"],"award-info":[{"award-number":["none"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>This study aimed to clarify whether infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is prevalent among the staff of a hospital providing treatment to patients with severe coronavirus disease 2019 (COVID-19) using radioligand assay (RLA). One thousand samples from the staff of a general hospital providing treatment to patients with severe COVID-19 were assayed for SARS-CoV-2 nucleocapsid protein (N) IgG using RLA. Nine patients with COVID-19 who had been treated in inpatient settings and had already recovered were used as control subjects, and 186 blood donor samples obtained more than 10 years ago were used as negative controls. Four of the 1000 samples showed apparently positive results, and approximately 10 or more samples showed slightly high counts. Interestingly, a few among the blood donor samples also showed slightly high values. To validate the results, antibody examinations using ELISA and neutralizing antibody tests were performed on 21 samples, and chemiluminescence immunoassay (CLIA) was performed on 201 samples, both resulting in a very high correlation. One blood donor sample showed slightly positive results in both RLA and CLIA, suggesting a cross-reaction. This study showed that five months after the pandemic began in Japan, the staff of a general hospital with a tertiary emergency medical facility had an extremely low seroprevalence of the antibodies against SARS-CoV-2. Further investigation will be needed to determine whether the slightly high results were due to cross-reactions or a low titer of anti-SARS-CoV-2 antibodies. The quantitative RLA was considered sensitive enough to detect low titers of antibodies.<\/jats:p>","DOI":"10.3390\/v13020347","type":"journal-article","created":{"date-parts":[[2021,2,23]],"date-time":"2021-02-23T20:19:36Z","timestamp":1614111576000},"page":"347","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Radioligand Assay-Based Detection of Antibodies against SARS-CoV-2 in Hospital Workers Treating Patients with Severe COVID-19 in Japan"],"prefix":"10.3390","volume":"13","author":[{"given":"Hidenori","family":"Matsunaga","sequence":"first","affiliation":[{"name":"Department of Psychiatry, Osaka General Medical Center, Osaka 558-8558, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Akiko","family":"Makino","sequence":"additional","affiliation":[{"name":"Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4050-2350","authenticated-orcid":false,"given":"Yasuhiro","family":"Kato","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Teruaki","family":"Murakami","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuta","family":"Yamaguchi","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Atsushi","family":"Kumanogoh","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine and Clinical Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuichiro","family":"Oba","sequence":"additional","affiliation":[{"name":"Department of General Medicine, Osaka General Medical Center, Osaka 558-8558, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Satoshi","family":"Fujimi","sequence":"additional","affiliation":[{"name":"Division of Trauma and Surgical Critical Care, Osaka General Medical Center, Osaka 558-8558, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tomoyuki","family":"Honda","sequence":"additional","affiliation":[{"name":"Division of Virology, Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keizo","family":"Tomonaga","sequence":"additional","affiliation":[{"name":"Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,23]]},"reference":[{"key":"ref_1","first-page":"671","article-title":"Detection by radioligand assay of antibodies against Borna disease virus in patients with various psychiatric disorders","volume":"12","author":"Matsunaga","year":"2005","journal-title":"Clin. 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