{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T16:34:28Z","timestamp":1791304468712,"version":"4.3.1"},"reference-count":42,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T00:00:00Z","timestamp":1769731200000},"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. Immunol."],"abstract":"\n Introduction<\/jats:title>\n \n Brucella<\/jats:italic>\n is a Gram-negative facultative intracellular bacterium that can cause fever, abortion, and other symptoms in humans and various mammals.\n btpB<\/jats:italic>\n , a type IV secretion system (T4SS) effector of\n Brucella<\/jats:italic>\n , plays a critical role in regulating\n Brucella<\/jats:italic>\n infection and inhibiting the host's innate immune response.\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n In this study, a\n btpB<\/jats:italic>\n mutant strain of\n Brucella<\/jats:italic>\n A19 (\u0394\n btpB<\/jats:italic>\n ) was constructed using homologous recombination, and its biological characteristics, virulence, and immunogenicity were systematically investigated.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n The results showed that \u0394\n btpB<\/jats:italic>\n exhibited weakened resistance to in vitro stress, while its growth characteristics did not differ significantly from the wild-type strain A19. In the mouse immunization model, \u0394\n btpB<\/jats:italic>\n induced weaker splenic pathological damage, and the splenic bacterial load was significantly lower than that of A19, indicating its reduced virulence. Additionally, \u0394\n btpB<\/jats:italic>\n infection elicited stronger humoral and cellular immune responses in mice, including higher antibody levels, increased levels of Th1 cytokines (such as IFN-\u03b3 and IL-2), and enhanced proliferation and activity of CD8+ cells. Detection of Th1 and Th2 cells revealed that \u0394\n btpB<\/jats:italic>\n induced stronger Th1 and Th2 responses in the spleen in the early stage, but the Th2 response weakened in the middle and late stages of infection. Notably, \u0394\n btpB<\/jats:italic>\n infection did not suppress natural killer (NK) cell activity and even significantly enhanced its cytotoxic activity compared to the A19 strain.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n \n Our research demonstrates that \u0394\n btpB<\/jats:italic>\n leads to a reduced survival capacity of\n Brucella<\/jats:italic>\n , while enhancing its immunogenicity. This suggests\n btpB<\/jats:italic>\n is an important target for the prevention of\n Brucella<\/jats:italic>\n .\n <\/jats:p>\n <\/jats:sec>","DOI":"10.3389\/fimmu.2026.1747903","type":"journal-article","created":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T06:44:25Z","timestamp":1769755465000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Enhanced immunogenicity of the Brucella A19 \u0394btpB mutant leads to accelerated clearance in the host"],"prefix":"10.3389","volume":"17","author":[{"given":"Ye","family":"Yuan","sequence":"first","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xuan","family":"Bu","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yunyi","family":"Zhai","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gaowa","family":"WuDong","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qing","family":"Lu","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ting","family":"Tang","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dong","family":"Zhou","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Liu","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yaping","family":"Jin","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Northwest A&F University","place":["Yangling, China"]},{"name":"Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University","place":["Yangling, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aihua","family":"Wang","sequence":"additional","affiliation":[{"name":"College of 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