{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T08:29:32Z","timestamp":1782289772240,"version":"3.54.5"},"reference-count":25,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T00:00:00Z","timestamp":1766361600000},"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":["2022YFD1800900"],"award-info":[{"award-number":["2022YFD1800900"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100007540","name":"Jiangsu Agriculture Science and Technology Innovation Fund","doi-asserted-by":"crossref","award":["CX(23)1029"],"award-info":[{"award-number":["CX(23)1029"]}],"id":[{"id":"10.13039\/100007540","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Jiangsu Province Industry University Research Cooperation Project","award":["BY20240104"],"award-info":[{"award-number":["BY20240104"]}]},{"DOI":"10.13039\/501100012246","name":"Priority Academic Program Development of Jiangsu Higher Education Institutions","doi-asserted-by":"publisher","award":["PAPD"],"award-info":[{"award-number":["PAPD"]}],"id":[{"id":"10.13039\/501100012246","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background\/Objectives: Lawsonia intracellularis (L. intracellularis) is an important intestinal pathogen that causes porcine proliferative enteropathy (PPE) in swine production worldwide. Currently, only a few commercially available vaccines are available for PPE prevention. Methods: In this study, an attenuated L. intracellularis variant of JS-G90 was obtained through subculturing of L. intracellularis JS isolates in McCoy cells for 90 generations, and its immune response was evaluated in pigs. Results: The results demonstrated that pigs who underwent intragastric administration of JS-G90 had lower fecal bacterial shedding and no histopathological lesions, indicating that it was safe in pigs. Therefore, JS-G90 was selected to develop the attenuated PPE vaccine. The immune response of JS-G90 in pigs was further evaluated based on fecal bacterial shedding, histopathological lesions, and humoral and cell-mediated immune responses following challenge with pathogenic L. intracellularis. The results revealed that JS-G90 significantly decreased the copies of L. intracellularis in rectal swabs containing feces and ileum infection (p &lt; 0.001), reduced histopathological lesions in the ileum, and elicited non-specific humoral (IgG and sIgA) and cell-mediated immune responses (p &lt; 0.001) compared with the challenge control and mock groups. Conclusions: In conclusion, the attenuated vaccine JS-G90 is safe and induced humoral and cell-mediated immune responses in pigs against pathogenic L. intracellularis infection. It may serve as an effective strategy for preventing and controlling PPE.<\/jats:p>","DOI":"10.3390\/vaccines14010015","type":"journal-article","created":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T16:19:26Z","timestamp":1766420366000},"page":"15","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Evaluation of a Newly Developed Live Attenuated Vaccine Candidate Against Lawsonia intracellularis"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1290-3245","authenticated-orcid":false,"given":"Huixing","family":"Lin","sequence":"first","affiliation":[{"name":"MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xuan","family":"Liu","sequence":"additional","affiliation":[{"name":"MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jingzhi","family":"Yuan","sequence":"additional","affiliation":[{"name":"MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ning","family":"Xiao","sequence":"additional","affiliation":[{"name":"MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hong","family":"Zhou","sequence":"additional","affiliation":[{"name":"MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongjie","family":"Fan","sequence":"additional","affiliation":[{"name":"MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China"},{"name":"College of Animal Science, Anhui Science and Technology University, Chuzhou 233100, China"},{"name":"Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,22]]},"reference":[{"key":"ref_1","first-page":"26","article-title":"Global patterns of porcine proliferative enteropathy","volume":"51","author":"McOrist","year":"2003","journal-title":"Pig J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"137","DOI":"10.54846\/jshap\/697","article-title":"Subclinical ileitis: Diagnostic and performance parameters in a multi-dose mucosal homogenate challenge model","volume":"20","author":"Paradis","year":"2012","journal-title":"J. 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