Immunogenicity and Protective Efficacy of a Recombinant Toxoplasma gondii GRA12 Vaccine in Domestic Cats

作者：Jinru Yang, Linchong Nie, Yining Song, Zipeng Yang, Liulu Yang, Hongjie Ren, Wenhao Li, Yasser S. Mahmmod, Xiu-Xiang Zhang, Zi‐Guo Yuan, Hao Yuan, Yue Zhang · 发表于：Vaccines · 年份：2025 · DOI：10.3390/vaccines13080851 · 被引用次数：4 · 研究领域：Toxoplasma gondii Research Studies、Herpesvirus Infections and Treatments、Rabies epidemiology and control

Background: Toxoplasma gondii (T. gondii) is a significant opportunistic zoonotic protozoan, presenting a substantial risk to human health and livestock. Consequently, the development of an effective vaccine against toxoplasmosis is imperative. This study focuses on the GRA12 protein as a target for developing a recombinant protein vaccine, with its efficacy evaluated through immunization trials in cats. Methods: We expressed recombinant GRA12 protein in E. coli and immunized cats with the purified antigen. The cats were categorized into four groups: G1 (PBS control), G2 (ISA 201 adjuvant alone), G3 (rGRA12 vaccine), and G4 (rGRA12 combined with ISA 201 adjuvant). All cats underwent subcutaneous immunizations on days 0, 14, and 28. Subsequently, serum levels of IgG (including IgG1 and IgG2a subclasses) and cytokines (IFN-γ, IL-2, TNF-α, IL-4, IL-10) were measured by enzyme-linked immunosorbent assay (ELISA). Two weeks after the third immunization (42 DPI), each cat was intraperitoneally infected with 1 × 106T. gondii RH tachyzoites. Oocyst shedding, survival duration, and T. gondii burden were monitored to assess vaccine-induced immunity. Results: The results indicate that immunization with recombinant rGRA12 protein significantly elevated IgG, IgG1, and IgG2a antibody levels in cats. G4 displayed elevated IgG levels post-immunization compared to G1 and G2, with an IgG1/IgG2a ratio > 1, indicating a mixed Th1/Th2 immune response. G4 also showed significantly increased IFN-...