{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T18:49:25Z","timestamp":1777661365969,"version":"3.51.4"},"reference-count":35,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,9,17]],"date-time":"2025-09-17T00:00:00Z","timestamp":1758067200000},"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. Cell. Infect. Microbiol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p><jats:italic>Salmonella<\/jats:italic> Enteritidis (<jats:italic>S<\/jats:italic>. Enteritidis) is an important zoonotic pathogen that poses a major threat to animals and human health. TrxB, as a key component of the thioredoxin system, is a thioredoxin reductase ubiquitously present in organisms. It is mainly involved in maintaining cellular redox balance, but its role in the pathogenicity of <jats:italic>S<\/jats:italic>. Enteritidis remains unclear.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>In this study, we generated a <jats:italic>trxB<\/jats:italic>-deficient strain from <jats:italic>S<\/jats:italic>. Enteritidis C50336 strain to investigate how TrxB affects the biological characteristics and pathogenesis of the bacterium. The virulence of \u0394<jats:italic>trxB<\/jats:italic> was assessed by measuring \u0394<jats:italic>trxB<\/jats:italic> resistance to environmental stress, biofilm formation ability, motility, adhesion, invasion ability, intracellular survival, LD<jats:sub>50<\/jats:sub>, virulence gene expression levels, and <jats:italic>in vivo<\/jats:italic> colonization ability. Additionally, the study measured specific IgG antibody levels in mice, lymphocyte proliferation, and the immunoprotective effect of \u0394<jats:italic>trxB<\/jats:italic>.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>We found that deletion of <jats:italic>trxB<\/jats:italic> gene did not affect the growth and biochemical properties of the <jats:italic>S<\/jats:italic>. Enteritidis strain but significantly reduced its motility, drug resistance, biofilm formation, and tolerance to environmental stress. After <jats:italic>trxB<\/jats:italic> knocked out, the adhesion and invasion capacities of <jats:italic>S<\/jats:italic>. Enteritidis to Caco-2 cells, along with its proliferation in RAW264.7 cells, were significantly reduced. Additionally, the <jats:italic>trxB<\/jats:italic>-deficient strain exhibited significantly lower pathogenicity than the parental strain, evidenced by a more than 100-fold increase in LD<jats:sub>50<\/jats:sub>. We also observed a significant decrease in the expression of virulence-related genes in the <jats:italic>trxB<\/jats:italic>-knockout mutant. More importantly, immunization with this deletion strain can confer promising protection against challenge with the C50336 strain.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>These findings indicate that TrxB is a crucial virulence factor in <jats:italic>S<\/jats:italic>. Enteritidis, playing critical roles in its pathogenicity.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fcimb.2025.1659729","type":"journal-article","created":{"date-parts":[[2025,9,17]],"date-time":"2025-09-17T05:43:28Z","timestamp":1758087808000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Characterization and immunoprotection of thioredoxin reductase TrxB knockout mutant of Salmonella Enteritidis"],"prefix":"10.3389","volume":"15","author":[{"given":"Siping","family":"Zhu","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lili","family":"Wang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hong","family":"Li","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chihuan","family":"Li","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xintong","family":"Zhu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chao","family":"Ren","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiaochen","family":"Liu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yulai","family":"Dong","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qiumei","family":"Shi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhiqiang","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2025,9,17]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"174","DOI":"10.1186\/1471-2180-12-174","article-title":"Acid stress response and protein induction in Campylobacter jejuni isolates with different acid tolerance","volume":"12","author":"Birk","year":"2012","journal-title":"BMC Microbiol."},{"key":"B2","doi-asserted-by":"publisher","first-page":"5140","DOI":"10.1128\/IAI.00449-06","article-title":"Thioredoxin 1 promotes intracellular replication and virulence of Salmonella enterica serovar Typhimurium","volume":"74","author":"Bjur","year":"2006","journal-title":"Infect. 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