{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:12:37Z","timestamp":1760148757222,"version":"build-2065373602"},"reference-count":44,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2023,5,27]],"date-time":"2023-05-27T00:00:00Z","timestamp":1685145600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>This study investigated the biological effects on circulating monocytes after challenge with SARS-CoV-2 recombinant spike protein. Whole blood collected from seven ostensibly healthy healthcare workers was incubated for 15 min with 2 and 20 ng\/mL final concentration of recombinant spike protein of Ancestral, Alpha, Delta, and Omicron variants. Samples were analyzed with Sysmex XN and DI-60 analyzers. Cellular complexity (i.e., the presence of granules, vacuoles and other cytoplasmic inclusions) increased in all samples challenged with the recombinant spike protein of the Ancestral, Alpha, and Delta variants, but not in those containing Omicron. The cellular content of nucleic acids was constantly decreased in most samples, achieving statistical significance in those containing 20 ng\/mL of Alpha and Delta recombinant spike proteins. The heterogeneity of monocyte volumes significantly increased in all samples, achieving statistical significance in those containing 20 ng\/mL of recombinant spike protein of the Ancestral, Alpha and Delta variants. The monocyte morphological abnormalities after spike protein challenge included dysmorphia, granulation, intense vacuolization, platelet phagocytosis, development of aberrant nuclei, and cytoplasmic extrusions. The SARS-CoV-2 spike protein triggers important monocyte morphological abnormalities, more evident in cells challenged with recombinant spike protein of the more clinically severe Alpha and Delta variants.<\/jats:p>","DOI":"10.3390\/ijms24119373","type":"journal-article","created":{"date-parts":[[2023,5,27]],"date-time":"2023-05-27T16:19:37Z","timestamp":1685204377000},"page":"9373","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effects of Different Types of Recombinant SARS-CoV-2 Spike Protein on Circulating Monocytes\u2019 Structure"],"prefix":"10.3390","volume":"24","author":[{"given":"Marco","family":"Vettori","sequence":"first","affiliation":[{"name":"Section of Clinical Biochemistry, University of Verona, 37129 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesco","family":"Dima","sequence":"additional","affiliation":[{"name":"Section of Clinical Biochemistry, University of Verona, 37129 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Brandon Michael","family":"Henry","sequence":"additional","affiliation":[{"name":"Clinical Laboratory, Division of Nephrology and Hypertension, Cincinnati Children\u2019s Hospital Medical Center, Cincinnati, OH 45229, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Giovanni","family":"Carpen\u00e8","sequence":"additional","affiliation":[{"name":"Section of Clinical Biochemistry, University of Verona, 37129 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6727-2081","authenticated-orcid":false,"given":"Matteo","family":"Gelati","sequence":"additional","affiliation":[{"name":"Section of Clinical Biochemistry, University of Verona, 37129 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Giovanni","family":"Celegon","sequence":"additional","affiliation":[{"name":"Section of Clinical Biochemistry, University of Verona, 37129 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gian Luca","family":"Salvagno","sequence":"additional","affiliation":[{"name":"Section of Clinical Biochemistry, University of Verona, 37129 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9523-9054","authenticated-orcid":false,"given":"Giuseppe","family":"Lippi","sequence":"additional","affiliation":[{"name":"Section of Clinical Biochemistry, University of Verona, 37129 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,27]]},"reference":[{"key":"ref_1","first-page":"e18136","article-title":"Pandemics Throughout the History","volume":"13","author":"Sampath","year":"2021","journal-title":"Cureus"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"504","DOI":"10.1136\/bmj.p504","article-title":"WHO keeps COVID-19 a public health emergency of international concern","volume":"380","author":"McVernon","year":"2023","journal-title":"BMJ"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"100847","DOI":"10.1016\/j.jbc.2021.100847","article-title":"Role of host factors in SARS-CoV-2 entry","volume":"297","author":"Evans","year":"2021","journal-title":"J. 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