{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:14:37Z","timestamp":1787026477218,"version":"build-2736575974"},"reference-count":50,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,5,14]],"date-time":"2021-05-14T00:00:00Z","timestamp":1620950400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>\n                    Human SP-D is a potent innate immune molecule whose presence at pulmonary mucosal surfaces allows its role in immune surveillance against pathogens. Higher levels of serum SP-D have been reported in the patients with severe acute respiratory syndrome coronavirus (SARS-CoV). Studies have suggested the ability of human SP-D to recognise spike glycoprotein of SARS-CoV; its interaction with HCoV-229E strain leads to viral inhibition in human bronchial epithelial (16HBE) cells. Previous studies have reported that a recombinant fragment of human SP-D (rfhSP-D) composed of 8 Gly-X-Y repeats, neck and CRD region, can act against a range of viral pathogens including influenza A Virus and Respiratory Syncytial Virus\n                    <jats:italic>in vitro<\/jats:italic>\n                    ,\n                    <jats:italic>in vivo<\/jats:italic>\n                    and\n                    <jats:italic>ex vivo<\/jats:italic>\n                    . In this context, this study was aimed at examining the likely protective role of rfhSP-D against SARS-CoV-2 infection. rfhSP-D showed a dose-responsive binding to S1 spike protein of SARS-CoV-2 and its receptor binding domain. Importantly, rfhSP-D inhibited interaction of S1 protein with the HEK293T cells overexpressing human angiotensin converting enzyme 2 (hACE2). The protective role of rfhSP-D against SARS-CoV-2 infection as an entry inhibitor was further validated by the use of pseudotyped lentiviral particles expressing SARS-CoV-2 S1 protein; ~0.5 RLU fold reduction in viral entry was seen following treatment with rfhSP-D (10 \u00b5g\/ml). These results highlight the therapeutic potential of rfhSP-D in SARS-CoV-2 infection and merit pre-clinical studies in animal models.\n                  <\/jats:p>","DOI":"10.3389\/fimmu.2021.641360","type":"journal-article","created":{"date-parts":[[2021,5,14]],"date-time":"2021-05-14T06:50:32Z","timestamp":1620975032000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":58,"title":["Human Surfactant Protein D Binds Spike Protein and Acts as an Entry Inhibitor of SARS-CoV-2 Pseudotyped Viral 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