{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T06:07:47Z","timestamp":1789625267236,"version":"build-2803163510"},"reference-count":51,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2023,3,24]],"date-time":"2023-03-24T00:00:00Z","timestamp":1679616000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2022YFD1800801, 2022YFD1800803"],"award-info":[{"award-number":["2022YFD1800801, 2022YFD1800803"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>Porcine epidemic diarrhea virus (PEDV) is a re-emerging enteropathogenic coronavirus that causes high mortality in neonatal piglets. The addition of trypsin plays a crucial role in the propagation of PEDV, but also increases the complexity of vaccine production and increases its cost. Previous studies have suggested that the S2\u2032 site and Y976\/977 of the PEDV spike (S) protein might be the determinants of PEDV trypsin independence. In this study, to achieve a recombinant trypsin-independent PEDV strain, we used trypsin-dependent genotype 2 (G2) PEDV variant AJ1102 to generate three recombinant PEDVs with mutations in S (S2\u2032 site R894G and\/or Y976H). The three recombinant PEDVs were still trypsin dependent, suggesting that the S2\u2032 site R894 and Y976 of AJ1102 S are not key sites for PEDV trypsin dependence. Therefore, we used AJ1102 and the classical trypsin-independent genotype 1 (G1) PEDV strain JS2008 to generate a recombinant PEDV carrying a chimeric S protein, and successfully obtained trypsin-independent PEDV strain rAJ1102-S2\u2032<jats:sub>JS2008<\/jats:sub>, in which the S2 (amino acids 894\u20131386) domain was replaced with the corresponding JS2008 sequence. Importantly, immunization with rAJ1102-S2\u2032<jats:sub>JS2008<\/jats:sub>induced neutralizing antibodies against both AJ1102 and JS2008. Collectively, these results suggest that rAJ1102-S2\u2032<jats:sub>JS2008<\/jats:sub>is a novel vaccine candidate with significant advantages, including no trypsin requirement for viral propagation to high titers and the potential provision of protection for pigs against G1 and G2 PEDV infections.<\/jats:p>","DOI":"10.3389\/fimmu.2023.1165606","type":"journal-article","created":{"date-parts":[[2023,3,24]],"date-time":"2023-03-24T06:09:13Z","timestamp":1679638153000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":9,"title":["Construction and immunogenicity of a trypsin-independent porcine epidemic diarrhea virus variant"],"prefix":"10.3389","volume":"14","author":[{"given":"Mingxiang","family":"Li","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yiye","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuxin","family":"Fang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shaobo","family":"Xiao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Puxian","family":"Fang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liurong","family":"Fang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2023,3,24]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/0378-1135(92)90135-g","article-title":"Coronavirus infection in mink (Mustela vison): Serological evidence of infection with a coronavirus related to transmissible gastroenteritis virus and porcine epidemic diarrhea virus","volume":"31","author":"Have","year":"1992","journal-title":"Vet Microbiol"},{"key":"B2","doi-asserted-by":"publisher","first-page":"59","DOI":"10.1016\/S0021-9975(05)80069-6","article-title":"An immunohistochemical investigation of porcine epidemic diarrhoea","volume":"113","author":"Sueyoshi","year":"1995","journal-title":"J Comp Pathol"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1023\/A:1011831902219","article-title":"Completion of the porcine epidemic diarrhoea coronavirus (PEDV) genome sequence","volume":"23","author":"Kocherhans","year":"2001","journal-title":"Virus Genes"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1292\/jvms1939.45.829","article-title":"An outbreak of swine diarrhea of a new-type associated with coronavirus-like particles in Japan","volume":"45","author":"Takahashi","year":"1983","journal-title":"Jpn J Vet Sci"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.01919-12","article-title":"Complete genome sequence of porcine epidemic diarrhea virus strain AJ1102 isolated from a suckling piglet with acute diarrhea in China","volume":"86","author":"Bi","year":"2012","journal-title":"J Virol"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.3201\/eid1803.120002","article-title":"New variants of porcine epidemic diarrhea virus, China","volume":"18","author":"Li","year":"2012","journal-title":"Emerg Infect Dis"},{"key":"B7","doi-asserted-by":"publisher","first-page":"195","DOI":"10.1186\/1743-422X-9-195","article-title":"Isolation and characterization of a variant porcine epidemic diarrhea virus in China","volume":"9","author":"Pan","year":"2012","journal-title":"Virol J"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.1007\/s00705-015-2353-y","article-title":"Genetic characterization of porcine epidemic diarrhea virus in Korea from 1998 to 2013","volume":"160","author":"Kim","year":"2015","journal-title":"Arch Virol"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.1007\/s00705-015-2522-z","article-title":"New porcine epidemic diarrhoea virus variant with a large deletion in the spike gene identified in domestic pigs","volume":"160","author":"Masuda","year":"2015","journal-title":"Arch Virol"},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1128\/genomeA.00753-14","article-title":"Complete genome sequence of porcine epidemic diarrhea virus in Vietnam","volume":"2","author":"Vui","year":"2014","journal-title":"Genome Announc"},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.1128\/genomeA.00634-15","article-title":"Complete genome sequences of two genetically distinct variants of porcine epidemic diarrhea virus in the eastern region of Thailand","volume":"3","author":"Cheun-Arom","year":"2015","journal-title":"Genome Announc"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1007\/s00705-016-2938-0","article-title":"Phylogenetic tracking of current porcine epidemic diarrhea virus (PEDV) strains in the Philippines","volume":"161","author":"Paraguison-Alili","year":"2016","journal-title":"Arch Virol"},{"key":"B13","doi-asserted-by":"publisher","DOI":"10.1128\/JCM.02820-13","article-title":"Isolation and characterization of porcine epidemic diarrhea viruses associated with the 2013 disease outbreak among swine in the united states","volume":"52","author":"Chen","year":"2014","journal-title":"J Clin Microbiol"},{"key":"B14","doi-asserted-by":"publisher","DOI":"10.3201\/eid2004.131685","article-title":"Pathology of US porcine epidemic diarrhea virus strain PC21A in gnotobiotic pigs","volume":"20","author":"Jung","year":"2014","journal-title":"Emerg Infect Dis"},{"key":"B15","doi-asserted-by":"publisher","DOI":"10.3201\/eid2005.131628","article-title":"Role of transportation in spread of porcine epidemic diarrhea virus infection, united states","volume":"20","author":"Lowe","year":"2014","journal-title":"Emerg Infect Dis"},{"key":"B16","doi-asserted-by":"publisher","DOI":"10.1177\/1040638713501675","article-title":"Emergence of porcine epidemic diarrhea virus in the united states: Clinical signs, lesions, and viral genomic sequences","volume":"25","author":"Stevenson","year":"2013","journal-title":"J Vet Diagn Invest"},{"key":"B17","doi-asserted-by":"publisher","first-page":"397","DOI":"10.1111\/tbed.12269","article-title":"Investigation into the role of potentially contaminated feed as a source of the first-detected outbreaks of porcine epidemic diarrhea in Canada","volume":"61","author":"Pasick","year":"2014","journal-title":"Transbound Emerg Dis"},{"key":"B18","doi-asserted-by":"publisher","DOI":"10.1128\/genomeA.00535-15","article-title":"Complete genome sequence of a porcine epidemic diarrhea s gene indel strain isolated in france in december 2014","volume":"3","author":"Grasland","year":"2015","journal-title":"Genome Announc"},{"key":"B19","doi-asserted-by":"publisher","DOI":"10.3201\/eid2103.141165","article-title":"Comparison of porcine epidemic diarrhea viruses from Germany and the united states, 2014","volume":"21","author":"Hanke","year":"2015","journal-title":"Emerg Infect Dis"},{"key":"B20","doi-asserted-by":"publisher","DOI":"10.3201\/eid2201.150544","article-title":"Porcine epidemic diarrhea virus and discovery of a recombinant swine enteric coronavirus, Italy","volume":"22","author":"Boniotti","year":"2016","journal-title":"Emerg Infect Dis"},{"key":"B21","doi-asserted-by":"publisher","first-page":"104553","DOI":"10.1016\/j.micpath.2020.104553","article-title":"Porcine epidemic diarrhea virus: Molecular mechanisms of attenuation and vaccines","volume":"149","author":"Li","year":"2020","journal-title":"Microb Pathog"},{"key":"B22","doi-asserted-by":"publisher","DOI":"10.1128\/jcm.26.11.2235-2239.1988","article-title":"Propagation of the virus of porcine epidemic diarrhea in cell culture","volume":"26","author":"Hofmann","year":"1988","journal-title":"J Clin Microbiol"},{"key":"B23","doi-asserted-by":"publisher","DOI":"10.1016\/S0264-410X(03)00027-6","article-title":"Differentiation of a vero cell adapted porcine epidemic diarrhea virus from Korean field strains by restriction fragment length polymorphism analysis of ORF 3","volume":"21","author":"Song","year":"2003","journal-title":"Vaccine"},{"key":"B24","doi-asserted-by":"publisher","first-page":"356","DOI":"10.1186\/s12917-017-1283-1","article-title":"Trypsin-independent porcine epidemic diarrhea virus US strain with altered virus entry mechanism","volume":"13","author":"Kim","year":"2017","journal-title":"BMC Vet Res"},{"key":"B25","doi-asserted-by":"publisher","DOI":"10.1016\/S0264-410X(99)00059-6","article-title":"Derivation of attenuated porcine epidemic diarrhea virus (PEDV) as vaccine candidate","volume":"17","author":"Kweon","year":"1999","journal-title":"Vaccine"},{"key":"B26","doi-asserted-by":"publisher","first-page":"44","DOI":"10.1186\/s13567-017-0449-y","article-title":"Identification of two mutation sites in spike and envelope proteins mediating optimal cellular infection of porcine epidemic diarrhea virus from different pathways","volume":"48","author":"Sun","year":"2017","journal-title":"Vet Res"},{"key":"B27","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.02453-20","article-title":"The trypsin-enhanced infection of porcine epidemic diarrhea virus is determined by the S2 subunit of the spike glycoprotein","volume":"95","author":"Tan","year":"2021","journal-title":"J Virol"},{"key":"B28","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.00297-14","article-title":"Proteolytic activation of the porcine epidemic diarrhea coronavirus spike fusion protein by trypsin in cell culture","volume":"88","author":"Wicht","year":"2014","journal-title":"J Virol"},{"key":"B29","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0809524106","article-title":"Activation of the SARS coronavirus spike protein via sequential proteolytic cleavage at two distinct sites","volume":"106","author":"Belouzard","year":"2009","journal-title":"Proc Natl Acad Sci USA"},{"key":"B30","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1407087111","article-title":"Host cell entry of middle East respiratory syndrome coronavirus after two-step, furin-mediated activation of the spike protein","volume":"111","author":"Millet","year":"2014","journal-title":"Proc Natl Acad Sci USA"},{"key":"B31","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.00959-09","article-title":"Two-step conformational changes in a coronavirus envelope glycoprotein mediated by receptor binding and proteolysis","volume":"83","author":"Matsuyama","year":"2009","journal-title":"J Virol"},{"key":"B32","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.02447-20","article-title":"The furin-S2' site in avian coronavirus plays a key role in central nervous system damage progression","volume":"95","author":"Cheng","year":"2021","journal-title":"J Virol"},{"key":"B33","doi-asserted-by":"publisher","DOI":"10.1128\/mbio.03739-21","article-title":"Molecular mechanism of porcine epidemic diarrhea virus cell tropism","volume":"13","author":"Li","year":"2022","journal-title":"mBio"},{"key":"B34","doi-asserted-by":"publisher","DOI":"10.1128\/genomeA.00105-13","article-title":"Complete genome sequence of a recombinant porcine epidemic diarrhea virus strain from eastern china","volume":"1","author":"Li","year":"2013","journal-title":"Genome Announc"},{"key":"B35","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.00700-14","article-title":"Porcine epidemic diarrhea virus nucleocapsid protein antagonizes beta interferon production by sequestering the interaction between IRF3 and TBK1","volume":"88","author":"Ding","year":"2014","journal-title":"J Virol"},{"key":"B36","doi-asserted-by":"publisher","first-page":"113772","DOI":"10.1016\/j.jviromet.2019.113772","article-title":"Rapid manipulation of the porcine epidemic diarrhea virus genome by CRISPR\/Cas9 technology","volume":"276","author":"Peng","year":"2020","journal-title":"J Virol Methods"},{"key":"B37","doi-asserted-by":"publisher","DOI":"10.1093\/oxfordjournals.aje.a118408","article-title":"A simple method of estimating fifty percent endpoints","volume":"27","author":"Reed","year":"1938","journal-title":"Am J Hyg"},{"key":"B38","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.00356-15","article-title":"A single point mutation creating a furin cleavage site in the spike protein renders porcine epidemic diarrhea coronavirus trypsin independent for cell entry and fusion","volume":"89","author":"Li","year":"2015","journal-title":"J Virol"},{"key":"B39","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.77.16.8801-8811.2003","article-title":"The coronavirus spike protein is a class I virus fusion protein: structural and functional characterization of the fusion core complex","volume":"77","author":"Bosch","year":"2003","journal-title":"J Virol"},{"key":"B40","doi-asserted-by":"publisher","first-page":"189","DOI":"10.1080\/10409230802058320","article-title":"Structures and mechanisms of viral membrane fusion proteins: Multiple variations on a common theme","volume":"43","author":"White","year":"2008","journal-title":"Crit Rev Biochem Mol Biol"},{"key":"B41","doi-asserted-by":"publisher","DOI":"10.3390\/v4061011","article-title":"Mechanisms of coronavirus cell entry mediated by the viral spike protein","volume":"4","author":"Belouzard","year":"2012","journal-title":"Viruses"},{"key":"B42","doi-asserted-by":"publisher","DOI":"10.1111\/tbed.13953","article-title":"Molecular characterization of porcine epidemic diarrhea virus associated with outbreaks in southwest China during 2014-2018","volume":"68","author":"Tian","year":"2021","journal-title":"Transbound Emerg Dis"},{"key":"B43","doi-asserted-by":"publisher","first-page":"87","DOI":"10.1186\/s13567-021-00954-6","article-title":"The spike glycoprotein genes of porcine epidemic diarrhea viruses isolated in China","volume":"52","author":"Wang","year":"2021","journal-title":"Vet Res"},{"key":"B44","doi-asserted-by":"crossref","DOI":"10.1016\/S1016-8478(23)15106-5","article-title":"Identification of the epitope region capable of inducing neutralizing antibodies against the porcine epidemic diarrhea virus","volume":"14","author":"Chang","year":"2002","journal-title":"Mol Cells"},{"key":"B45","doi-asserted-by":"publisher","first-page":"28","DOI":"10.1016\/j.virol.2006.04.027","article-title":"Phage-displayed peptides having antigenic similarities with porcine epidemic diarrhea virus (PEDV) neutralizing epitopes","volume":"354","author":"Cruz","year":"2006","journal-title":"Virology"},{"key":"B46","doi-asserted-by":"publisher","first-page":"73","DOI":"10.1016\/j.vetmic.2008.02.022","article-title":"Identification of two novel b cell epitopes on porcine epidemic diarrhea virus spike protein","volume":"131","author":"Sun","year":"2008","journal-title":"Vet Microbiol"},{"key":"B47","doi-asserted-by":"publisher","DOI":"10.1016\/j.virusres.2007.10.015","article-title":"The GPRLQPY motif located at the carboxy-terminal of the spike protein induces antibodies that neutralize porcine epidemic diarrhea virus","volume":"132","author":"Cruz","year":"2008","journal-title":"Virus Res"},{"key":"B48","doi-asserted-by":"publisher","first-page":"890","DOI":"10.3390\/v14050890","article-title":"Evaluation of the immunogenicity in mice orally immunized with recombinant Lactobacillus casei expressing porcine epidemic diarrhea virus S1 protein","volume":"14","author":"Xiao","year":"2022","journal-title":"Viruses"},{"key":"B49","doi-asserted-by":"publisher","first-page":"BSR20182028","DOI":"10.1042\/BSR20182028","article-title":"Mucosal immune responses induced by oral administration recombinant bacillus subtilis expressing the COE antigen of PEDV in newborn piglets","volume":"39","author":"Wang","year":"2019","journal-title":"Biosci Rep"},{"key":"B50","doi-asserted-by":"publisher","DOI":"10.1016\/j.vaccine.2018.01.086","article-title":"PED subunit vaccine based on COE domain replacement of flagellin domain D3 improved specific humoral and mucosal immunity in mice","volume":"36","author":"Li","year":"2018","journal-title":"Vaccine"},{"key":"B51","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2020.02152","article-title":"Plant-derived trimeric co-26k-equivalent epitope induced neutralizing antibodies against porcine epidemic diarrhea virus","volume":"11","author":"Ho","year":"2020","journal-title":"Front Immunol"}],"container-title":["Frontiers in Immunology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fimmu.2023.1165606\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,10,16]],"date-time":"2024-10-16T23:07:39Z","timestamp":1729120059000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fimmu.2023.1165606\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,3,24]]},"references-count":51,"alternative-id":["10.3389\/fimmu.2023.1165606"],"URL":"https:\/\/doi.org\/10.3389\/fimmu.2023.1165606","relation":{},"ISSN":["1664-3224"],"issn-type":[{"value":"1664-3224","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,3,24]]},"article-number":"1165606"}}