Zhang Zhenchao, Li Yuhua, Liang Yuanyuan, Wang Shuai, Xie Qing, Nan Xiaoxu, Li Pengju, Hong Gaigai, Liu Qingqing, Li Xiangrui
School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan, 453003, PR China.
The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan, 453003, PR China.
Vet Parasitol. 2018 Aug 30;260:12-21. doi: 10.1016/j.vetpar.2018.06.016. Epub 2018 Jun 24.
Toxoplasma gondii rhoptry proteins (TgROPs) have been considered the main targets and indicator molecules for immune diagnosis and prophylaxis because they present during the initial process of invasion. The aim of this study was to evaluate the protective effect of a TgROP35 DNA vaccine on experimental mice subjected to T. gondii challenge. The effect of intramuscularly injecting the genetic vaccine pVAX-ROP35 into BALB/c mice was evaluated, by first inserting the TgROP35 sequence into the pVAX I eukaryotic expression vector. The levels of IgG, IgG1 and IgG2a in pVAX-ROP35-vaccinated animals were integrally increased. Cytokine profile analyses revealed that IFN-γ, IL-2 and IL-10 levels were significantly increased, while there were no significant differences in IL-4 expression between the pVAX-ROP35 immunized and control groups. Additionally, we found that immunization with pVAX-ROP35 significantly prolonged the survival time (13.90 ± 1.97 days) of mice after challenge infection with the virulent T. gondii RH strain compared with that in non-vaccinated control animals (mice died within 10 days). Moreover, the number of brain cysts (1450 ± 287) in the animals subjected to pVAX-TgROP35 vaccination decreased remarkably (P < 0.05) compared to that in the blank control mice (2333 ± 473). Furthermore, the size of brain cysts in the pVAX-TgROP35 group was significantly smaller than that in the blank control, PBS and pVAXI groups. The findings indicated that intense cell-mediated and humoural immunity was triggered and that defence mechanisms against T. gondii were partially induced after vaccination by TgROP35.
弓形虫棒状体蛋白（TgROPs）被认为是免疫诊断和预防的主要靶点及指示分子，因为它们在入侵的初始过程中就会出现。本研究的目的是评估TgROP35 DNA疫苗对经弓形虫攻击的实验小鼠的保护作用。通过首先将TgROP35序列插入pVAX I真核表达载体，评估了将基因疫苗pVAX-ROP35肌肉注射到BALB/c小鼠中的效果。接种pVAX-ROP35的动物体内IgG、IgG1和IgG2a水平整体升高。细胞因子谱分析显示，IFN-γ、IL-2和IL-10水平显著升高，而pVAX-ROP35免疫组和对照组之间IL-4表达无显著差异。此外，我们发现，与未接种疫苗的对照动物（小鼠在10天内死亡）相比，用pVAX-ROP35免疫显著延长了感染强毒株弓形虫RH株的小鼠的存活时间（13.90±1.97天）。而且，接种pVAX-TgROP35的动物脑囊肿数量（1450±287）与空白对照小鼠（2333±473）相比显著减少（P<0.05）。此外，pVAX-TgROP35组脑囊肿的大小明显小于空白对照、PBS和pVAXI组。这些发现表明，接种TgROP35疫苗后引发了强烈的细胞介导免疫和体液免疫，部分诱导了针对弓形虫的防御机制。
