{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,9]],"date-time":"2026-08-09T04:42:02Z","timestamp":1786250522487,"version":"build-2736575974"},"reference-count":44,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T00:00:00Z","timestamp":1786060800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100011002","name":"NSFC-Yunnan Joint Fund","doi-asserted-by":"crossref","award":["U2202201"],"award-info":[{"award-number":["U2202201"]}],"id":[{"id":"10.13039\/501100011002","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Science and Technology Innovation Program of Shanxi Agricultural University","award":["2023BQ62"],"award-info":[{"award-number":["2023BQ62"]}]},{"award":["2023BQ62"],"award-info":[{"award-number":["2023BQ62"]}],"id":[{"id":"https:\/\/ror.org\/05e9f5362","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Special Research Fund of Shanxi Agricultural University for High-level Talents","award":["2021XG001"],"award-info":[{"award-number":["2021XG001"]}]},{"award":["2021XG001"],"award-info":[{"award-number":["2021XG001"]}],"id":[{"id":"https:\/\/ror.org\/05e9f5362","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>Toxoplasma gondii is an obligate intracellular apicomplexan parasite that poses serious risks to immunocompromised individuals and the global livestock industry. Our previous study showed that AP2X-1 regulates stage conversion and virulence of T. gondii; however, whether AP2X-1-deficient strains can serve as live-attenuated vaccine candidates is unknown. Here, we evaluated the in vivo virulence, protective efficacy, and induced immunity of the ap2X-1 knockout strain Pru\u0394ap2X-1. In Kunming mice, infection with even the highest tested dose (5 \u00d7 106 tachyzoites) of Pru\u0394ap2X-1 resulted in 100% survival without detectable brain cysts. Vaccination with 106 Pru\u0394ap2X-1 tachyzoites conferred complete protection (100% survival) against acute challenge with homologous type II Pru or heterologous ToxoDB#9 PYS strains, whereas control mice exhibited only 0% to 16.7% survival. Moreover, immunized mice orally challenged with Pru cysts showed 100% survival, and no brain cysts were detected under the conditions tested, compared with only 30% survival in control mice challenged with 10 cysts and no survival with 40 cysts. The vaccination induced a Th1-biased response as evidenced by significantly elevated T. gondii-specific total IgG, IgG2a, and the Th1 cytokines IFN-\u03b3 and IL-2, along with a significantly reduced IgG1\/IgG2a ratio. Collectively, the attenuated Pru\u0394ap2X-1 strain generates strong protective immunity against acute and chronic infection with low-virulence strains (the type II Pru and ToxoDB#9 PYS), as well as partial protection against the hypervirulent type I RH strain, positioning it as a potential candidate for a live-attenuated vaccine, with a favorable safety profile observed under the experimental conditions.<\/jats:p>","DOI":"10.3390\/ani16162453","type":"journal-article","created":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T09:14:28Z","timestamp":1786094068000},"page":"2453","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Live Attenuated AP2X-1-Deficient Toxoplasma Strain Confers Protective Immunity Against Acute and Chronic Toxoplasmosis in a Murine Model"],"prefix":"10.3390","volume":"16","author":[{"given":"Wen-Bo","family":"Hao","sequence":"first","affiliation":[{"name":"Shanxi Key Laboratory of Animal Disease Research, Prevention and Control, College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong 030801, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li-Xiu","family":"Sun","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, School of Basic Medical Sciences, Dali University, Dali 671000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ru-Shi","family":"Tu","sequence":"additional","affiliation":[{"name":"Shanxi Key Laboratory of Animal Disease Research, Prevention and Control, College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong 030801, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-6974-4472","authenticated-orcid":false,"given":"Zhi","family":"Zheng","sequence":"additional","affiliation":[{"name":"Shanxi Key Laboratory of Animal Disease Research, Prevention and Control, College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong 030801, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chen-Ran","family":"Tian","sequence":"additional","affiliation":[{"name":"Shanxi Key Laboratory of Animal Disease Research, Prevention and Control, College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong 030801, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2530-4628","authenticated-orcid":false,"given":"Xing-Quan","family":"Zhu","sequence":"additional","affiliation":[{"name":"Shanxi Key Laboratory of Animal Disease Research, Prevention and Control, College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong 030801, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-6224-3603","authenticated-orcid":false,"given":"Xiao-Nan","family":"Zheng","sequence":"additional","affiliation":[{"name":"Shanxi Key Laboratory of Animal Disease Research, Prevention and Control, College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong 030801, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,7]]},"reference":[{"key":"ref_1","first-page":"898","article-title":"Global status of Toxoplasma gondii infection: Systematic review and prevalence snapshots","volume":"36","author":"Molan","year":"2019","journal-title":"Trop. 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