Key Points Vaccination with RHΔtkl1 in mice induces a strong humoral and cellular response. RHΔtkl1-vaccinated mice are protected against acute, chronic, and congenital toxoplasmosis. Immunity induced by RHΔtkl1 vaccine is primarily Th1 biased and CD8+ T cell mediated. In this study, we generated a tkl1 deletion mutant in the Toxoplasma gondii type 1 RH (RHΔtkl1) strain and tested the protective efficacies of vaccination using RHΔtkl1 tachyzoites against acute, chronic, and congenital T. gondii infections in Kunming mice. Mice vaccinated with RHΔtkl1 mounted a strong humoral and cellular response as shown by elevated levels of anti–T. gondii–specific IgG, IL-2, IL-12, IFN-γ, and IL-10. All RHΔtkl1-vaccinated mice survived a lethal challenge with 1 × 103 tachyzoites of type 1 RH or ToxoDB#9 (PYS or TgC7) strain as well as 100 cysts or oocysts of Prugniuad strain. All mock-vaccinated plus infected mice have died. Vaccination also protected against cyst- or oocyst-caused chronic infection, reduced vertical transmission caused by oocysts, increased litter size, and maintained body weight of pups born to dams challenged with 10 oocysts on day 5 of gestation. In contrast, all mock-vaccinated plus oocysts-infected dams had aborted, and no fetus has survived. Vaccinated dams remained healthy postinfection, and their brain cyst burden was significantly reduced compared with mock-vaccinated dams infected with oocysts. In vivo depletion of CD4+ T cells, CD8+ T cells, and B cells revealed that CD8+ T cells are involved in the protection of mice against T. gondii infection. Additionally, adoptive transfer of CD8+ T cells from RHΔtkl1-vaccinated mice significantly enhanced the survival of naive mice infected with the pathogenic strain. Together, these data reaffirm the importance of CD8+ T cell responses in future vaccine design for toxoplasmosis and present T. gondii tkl1 gene as a promising vaccine candidate.

中文翻译：

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Toxoplasma gondii tkl1 缺失突变体是一种有前景的针对小鼠急性、慢性和先天性弓形体病的疫苗

关键点 在小鼠中接种 RHΔtkl1 可诱导强烈的体液和细胞反应。RHΔtkl1 疫苗接种小鼠可预防急性、慢性和先天性弓形虫病。RHΔtkl1 疫苗诱导的免疫主要是 Th1 偏向和 CD8+ T 细胞介导的。在这项研究中，我们在 1 型弓形虫 RH (RHΔtkl1) 菌株中产生了 tkl1 缺失突变体，并测试了使用 RHΔtkl1 速殖子接种疫苗对昆明小鼠急性、慢性和先天性弓形虫感染的保护功效。接种 RHΔtkl1 的小鼠产生了强烈的体液和细胞反应，如抗 T 水平升高所示。弓形虫特异性 IgG、IL-2、IL-12、IFN-γ 和 IL-10。所有 RHΔtkl1 疫苗接种的小鼠都能在 1 × 103 1 型 RH 或 ToxoDB#9（PYS 或 TgC7）株系的速殖子以及 Prugniuad 株系的 100 个包囊或卵囊的致命攻击中存活下来。所有模拟接种加感染的小鼠均已死亡。接种疫苗还可以防止囊肿或卵囊引起的慢性感染，减少由卵囊引起的垂直传播，增加窝产仔数，并保持在妊娠第 5 天受到 10 个卵囊攻击的母猪所生幼崽的体重。相比之下，所有模拟接种加卵囊感染的母猪都流产了，没有胎儿存活。接种疫苗的母猪在感染后保持健康，与感染卵囊的模拟接种母猪相比，它们的脑囊肿负担显着降低。CD4+ T 细胞、CD8+ T 细胞的体内耗竭，和 B 细胞表明 CD8+ T 细胞参与保护小鼠免受弓形虫感染。此外，来自 RHΔtkl1 疫苗接种小鼠的 CD8+ T 细胞的过继转移显着提高了感染致病菌株的幼稚小鼠的存活率。总之，这些数据重申了 CD8+ T 细胞反应在未来弓形虫病疫苗设计中的重要性，并将 T. gondii tkl1 基因作为一种有前途的候选疫苗。