{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,30]],"date-time":"2026-10-30T17:47:09Z","timestamp":1793382429562,"version":"4.5.0"},"reference-count":31,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2023,12,18]],"date-time":"2023-12-18T00:00:00Z","timestamp":1702857600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:sec><jats:title>Introduction<\/jats:title><jats:p>Swine serve as an important intermediate host species for generating novel influenza A viruses (IAVs) with pandemic potential because of the host\u2019s susceptibility to IAVs of swine, human and avian origin. Primary respiratory cell lines are used in IAV research to model the host\u2019s upper respiratory tract <jats:italic>in vitro<\/jats:italic>. However, primary cell lines are limited by their passaging capacity and are time-consuming for use in industry and research pipelines. We were interested in developing and characterizing a biologically relevant immortalized swine respiratory cell line that could be used for efficient propagation and characterization of swine IAV isolates.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Lung tissue for the generation of primary swine respiratory cells were isolated from the bronchi of an 8-week-old Yorkshire\/Hampshire pig, which were immortalized by transduction of the SV40 T antigen using a lentivirus vector. The transduction of the SV40 T antigen was confirmed by Real Time RT-PCR in cells passaged greater than twenty times.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Immortalized swine respiratory cells expressed primarily \u03b12,6 sialic acid receptors and were susceptible to both swine and human IAVs, with swine viruses exhibiting higher replication rates. Notably, infection with a swine H3N2 isolate prompted increased IL-6 and IL-1\u03b1 protein secretion compared to a seasonal human H3N2 virus. Even after 20 passages, the immortalized cells maintained the primary respiratory cell phenotype and remained permissive to IAV infection without exogenous trypsin.<\/jats:p><\/jats:sec><jats:sec><jats:title>Discussion<\/jats:title><jats:p>In summary, our developed immortalized swine respiratory cell line offers an alternative <jats:italic>in vitro<\/jats:italic> substrate for studying IAV replication and transmission dynamics in pigs, overcoming the limitations of primary respiratory cells in terms of low passage survivability and cost.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fvets.2023.1258269","type":"journal-article","created":{"date-parts":[[2023,12,18]],"date-time":"2023-12-18T12:18:58Z","timestamp":1702901938000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":4,"title":["Development and characterization of an immortalized swine respiratory cell line for influenza A virus research"],"prefix":"10.3389","volume":"10","author":[{"given":"Peter J.","family":"Neasham","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vasilis C.","family":"Pliasas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J. Fletcher","family":"North","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Celeste","family":"Johnson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S. Mark","family":"Tompkins","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Constantinos S.","family":"Kyriakis","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2023,12,18]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"81650","DOI":"10.3390\/ijms18081650","article-title":"Evolution of influenza A virus by mutation and re-assortment","volume":"18","author":"Shao","year":"2017","journal-title":"Int J Mol Sci"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"73","DOI":"10.1186\/1465-9921-8-73","article-title":"Sialic acid receptor detection in the human respiratory tract: evidence for widespread distribution of potential binding sites for human and avian influenza viruses","volume":"8","author":"Nicholls","year":"2007","journal-title":"Respir Res"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"e21183","DOI":"10.1371\/journal.pone.0021183","article-title":"Avian influenza viruses infect primary human bronchial epithelial cells unconstrained by sialic acid alpha2,3 residues","volume":"6","author":"Oshansky","year":"2011","journal-title":"PLoS One"},{"key":"ref4","doi-asserted-by":"publisher","first-page":"434","DOI":"10.1186\/1743-422X-8-434","article-title":"Distribution of sialic acid receptors and influenza A virus of avian and swine origin in experimentally infected pigs","volume":"8","author":"Trebbien","year":"2011","journal-title":"Virol J"},{"key":"ref5","first-page":"35","article-title":"Sialyloligosaccharides of the respiratory epithelium in the selection of human influenza virus receptor specificity","volume":"40","author":"Baum","year":"1990","journal-title":"Acta Histochem Suppl"},{"key":"ref6","doi-asserted-by":"publisher","first-page":"160","DOI":"10.1016\/j.coviro.2012.03.003","article-title":"The role of receptor binding specificity in interspecies transmission of influenza viruses","volume":"2","author":"Imai","year":"2012","journal-title":"Curr Opin Virol"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"65","DOI":"10.1159\/000157337","article-title":"Practise, PIgs as \u2018mixing vessels\u2019 for the creation of new pandemic influenza","volume":"2","author":"Scholtissek","year":"2004","journal-title":"Med Princ Pract"},{"key":"ref8","doi-asserted-by":"publisher","first-page":"158","DOI":"10.4172\/1747-0862.1000028","article-title":"AJJom, research gmaijob. 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