{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T01:07:44Z","timestamp":1789780064442,"version":"4.0.1"},"reference-count":39,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2025,1,31]],"date-time":"2025-01-31T00:00:00Z","timestamp":1738281600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Hainan Provincial Natural Science Foundation of China","award":["823RC468"],"award-info":[{"award-number":["823RC468"]}]},{"name":"Hainan Provincial Natural Science Foundation of China","award":["KYQD(ZR)1936"],"award-info":[{"award-number":["KYQD(ZR)1936"]}]},{"name":"Hainan Provincial Natural Science Foundation of China","award":["HNARS2022-2-G05"],"award-info":[{"award-number":["HNARS2022-2-G05"]}]},{"name":"Hainan university scientific research start-up fund","award":["823RC468"],"award-info":[{"award-number":["823RC468"]}]},{"name":"Hainan university scientific research start-up fund","award":["KYQD(ZR)1936"],"award-info":[{"award-number":["KYQD(ZR)1936"]}]},{"name":"Hainan university scientific research start-up fund","award":["HNARS2022-2-G05"],"award-info":[{"award-number":["HNARS2022-2-G05"]}]},{"name":"earmarked fund for the Agriculture Research System in Hainan Province","award":["823RC468"],"award-info":[{"award-number":["823RC468"]}]},{"name":"earmarked fund for the Agriculture Research System in Hainan Province","award":["KYQD(ZR)1936"],"award-info":[{"award-number":["KYQD(ZR)1936"]}]},{"name":"earmarked fund for the Agriculture Research System in Hainan Province","award":["HNARS2022-2-G05"],"award-info":[{"award-number":["HNARS2022-2-G05"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background: Salmonella\u00a0Typhimurium poses a substantial health risk to both humans and animals. This study evaluated the potential of using the Salmonella\u00a0Typhimurium \u0394sptP mutant as a live-attenuated vaccine candidate by constructing it through homologous recombination and assessing its key biological properties, including growth characteristics, immunogenicity, and protective efficacy. Methods: We generated the \u0394sptP mutant through targeted gene deletion, ensuring the preservation of the bacterial strain\u2019s growth and stability. In vitro and in vivo assays were performed to compare the invasive capabilities between the mutant and the wild-type strains. Specifically, we examined the invasion into RAW264.7 murine macrophages and mice. Furthermore, the virulence of the mutant was evaluated by determining the median lethal dose (LD50). To evaluate immunogenicity and protection, mice were immunized with 2 \u00d7 104 CFUs of the \u0394sptP mutant, followed by a booster immunization, and then challenged with a virulent strain. Results: The \u0394sptP mutant exhibited no significant changes in growth characteristics or genetic stability compared to the wild-type strain. However, it demonstrated a significantly diminished capacity for invasion in both murine macrophages and mice. The LD50 for the mutant was 39.92-fold higher than that of the wild-type, indicating a marked reduction in virulence. Mice immunized with the \u0394sptP mutant and administered a booster immunization exhibited 87.5% protection against challenge with a virulent strain, as compared to the PBS control group. Moreover, the mutant induced IgG antibody levels comparable to those induced by the wild-type strain. Conclusions: The \u0394sptP mutant of Salmonella\u00a0Typhimurium exhibits markedly reduced virulence while retaining robust immunogenicity and protective efficacy. These findings suggest that the \u0394sptP mutant is a promising candidate for a live-attenuated vaccine, potentially providing an effective strategy to prevent Salmonella\u00a0Typhimurium infections.<\/jats:p>","DOI":"10.3390\/vaccines13020150","type":"journal-article","created":{"date-parts":[[2025,1,31]],"date-time":"2025-01-31T09:16:26Z","timestamp":1738314986000},"page":"150","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Characterization and Protective Efficacy of a Salmonella\u00a0Typhimurium ATCC 14028 sptP Mutant as a Live Attenuated Vaccine Candidate"],"prefix":"10.3390","volume":"13","author":[{"given":"Nanlong","family":"Zhou","sequence":"first","affiliation":[{"name":"School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yonghui","family":"Ding","sequence":"additional","affiliation":[{"name":"School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ting","family":"He","sequence":"additional","affiliation":[{"name":"School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuling","family":"Sun","sequence":"additional","affiliation":[{"name":"School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongfang","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meiling","family":"Huang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Key Laboratory for Research and Development of Tropical Herbs, School of Pharmacy, Hainan Medical University, Haikou 571199, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tiansen","family":"Li","sequence":"additional","affiliation":[{"name":"School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,1,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"e00079-18","DOI":"10.1128\/IAI.00079-18","article-title":"Genome Variation and Molecular Epidemiology of Salmonella Enterica Serovar Typhimurium Pathovariants","volume":"86","author":"Branchu","year":"2018","journal-title":"Infect. 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