Du Rongqi, He Jinling, Meng Jiali, Zhang Dongchao, Li Danruo, Wang Hui, Fan Aili, Xu Gang, Ma Shuhui, Zuo Zonghui, Song Qiqi, Jin Tianming
Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Husbandry, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin, 300392, China.
Beijing Institute of Heart Lung and Blood Vessel Diseases, Beijing Anzhen Hospital Capital Medical University, Beijing, 100029, China.
Parasitol Res. 2024 Dec 26;123(12):420. doi: 10.1007/s00436-024-08435-3.
Toxoplasmosis is a foodborne zoonotic parasitic disease caused by Toxoplasma gondii, which seriously threatens to human health and causes economic losses. At present, there is no effective vaccine strategy for the prevention and control of toxoplasmosis. T. gondii rhoptry proteins (ROPs) are important proteins secreted by the parasite during the early stage of invasion into host cells. In this study, we constructed six individual plasmids (pVAX1-ROP2, pVAX1-ROP5, pVAX1-ROP9, pVAX1-ROP16, pVAX1-ROP17, and pVAX1-ROP18) encoding T. gondii rhoptry proteins and then used an equimolar amount of each as a vaccine cocktail. Following booster immunization, serum antibody levels, splenic lymphocyte proliferation, cytokine production, and survival time after infection with T. gondii RH strain were measured in immunized mice. The results showed that the mice immunized with the DNA vaccine cocktail developed a higher level of the specific anti-T. gondii IgG in serum and the cytokines such as IFN-γ, IL-2, IL-12, and IL-4 (P < 0.01). The stimulation index (SI) of spleen lymphocytes (P < 0.01), the frequencies of CD4 T lymphocytes (P < 0.01), and the ratio of CD4/CD8 T lymphocytes (P < 0.05 or P < 0.01) in the vaccine-immunized mice were significantly increased compared to the control group. After challenge with the virulent T. gondii RH strain tachyzoites, the survival time of mice in the DNA vaccine cocktail group (18.1 ± 1.81 d) was significantly longer (P < 0.01) than that in the control group (8.4 ± 1.02 or 7.9 ± 0.83 d). The results indicated that the DNA vaccine cocktail could elicit strong humoral and cellular immune responses in mice and could also improve the resistance of mice to acute T. gondii infection.
弓形虫病是一种由刚地弓形虫引起的食源性人畜共患寄生虫病，严重威胁人类健康并造成经济损失。目前，尚无有效的疫苗策略用于预防和控制弓形虫病。刚地弓形虫棒状体蛋白（ROPs）是该寄生虫在侵入宿主细胞早期分泌的重要蛋白质。在本研究中，我们构建了六个编码刚地弓形虫棒状体蛋白的单个质粒（pVAX1-ROP2、pVAX1-ROP5、pVAX1-ROP9、pVAX1-ROP16、pVAX1-ROP17和pVAX1-ROP18），然后将等摩尔量的每种质粒用作疫苗混合物。加强免疫后，在免疫小鼠中测量血清抗体水平、脾淋巴细胞增殖、细胞因子产生以及感染刚地弓形虫RH株后的存活时间。结果显示，用DNA疫苗混合物免疫的小鼠血清中产生了更高水平的特异性抗弓形虫IgG以及细胞因子如IFN-γ、IL-2、IL-12和IL-4（P < 0.01）。与对照组相比，疫苗免疫小鼠的脾淋巴细胞刺激指数（SI）（P < 0.01）、CD4 T淋巴细胞频率（P < 0.01）以及CD4/CD8 T淋巴细胞比率（P < 0.05或P < 0.01）显著增加。在用强毒刚地弓形虫RH株速殖子攻击后，DNA疫苗混合物组小鼠的存活时间（18.1 ± 1.81天）明显长于对照组（8.4 ± 1.02或7.9 ± 0.83天）（P < 0.01）。结果表明，DNA疫苗混合物可在小鼠中引发强烈的体液和细胞免疫反应，还可提高小鼠对急性弓形虫感染的抵抗力。
