{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,8]],"date-time":"2026-08-08T04:43:46Z","timestamp":1786164226696,"version":"build-2736575974"},"reference-count":42,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T00:00:00Z","timestamp":1785974400000},"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":"National Key Research and Development Program of China","award":["2021YFC2300800"],"award-info":[{"award-number":["2021YFC2300800"]}]},{"name":"National Key Research and Development Program of China","award":["2021YFC2300802"],"award-info":[{"award-number":["2021YFC2300802"]}]},{"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":["Microorganisms"],"abstract":"<jats:p>Toxoplasmosis, caused by Toxoplasma gondii, remains an important zoonotic disease affecting both human and animal health, particularly in immunocompromised individuals and during pregnancy. Current treatments are unable to eliminate latent tissue cysts and are further limited by adverse effects and prolonged treatment regimens, highlighting the need for effective vaccines. In this study, we evaluated the virulence attenuation and protective efficacy of a CRISPR\u2013Cas9-generated rhoptry protein 64 knockout strain (RH\u0394rop64) as a live attenuated vaccine candidate in Kunming mice. RH\u0394rop64 exhibited markedly reduced virulence, and mice tolerated doses of up to 1 \u00d7 102 tachyzoites without obvious clinical signs. Immunization provided substantial protection against acute challenge with the parental RH\u0394ku80 and ToxoDB#9 (PYS) strains at 30 days post-vaccination and partial protection against type II (Pru) tachyzoites. In addition, all immunized mice survived following oral challenge with 10 or 40 Pru cysts and exhibited reduced brain cyst burdens among surviving mice. Vaccination also induced measurable humoral and cytokine responses, characterized by increased levels of T. gondii-specific IgG and cytokines that were maintained for at least 75 days post-vaccination. These results suggest that RH\u0394rop64 has the potential to serve as a live attenuated vaccine candidate, providing substantial, although incomplete, protection against acute challenge with the three T. gondii strains tested and being associated with reduced brain cyst burdens among surviving mice following chronic challenge. Further evaluation is required to determine its safety and applicability as a vaccine candidate for food-producing animals and cats.<\/jats:p>","DOI":"10.3390\/microorganisms14081725","type":"journal-article","created":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T08:08:02Z","timestamp":1786003682000},"page":"1725","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["ROP64-Deficient\u00a0Toxoplasma gondii Strain Confers Protection Against Acute and Chronic Toxoplasmosis in Mice"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-6974-4472","authenticated-orcid":false,"given":"Zhi","family":"Zheng","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":"Shi-Bo","family":"Huang","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":"Yi-Rong","family":"Ma","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":"Wen-Bo","family":"Hao","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"}]},{"given":"Hong-Yu","family":"Song","sequence":"additional","affiliation":[{"name":"School of Basic Medical Sciences, Changzhi Medical College, Changzhi 046000, 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"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"e00115-19","DOI":"10.1128\/CMR.00115-19","article-title":"Epidemiology, pathophysiology, diagnosis, and management of cerebral toxoplasmosis","volume":"34","author":"Elsheikha","year":"2021","journal-title":"Clin. 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