Ege University, Graduate School of Natural and Applied Sciences, Department of Biotechnology, İzmir, Türkiye; Ege University, Vaccine Development Application and Research Center, İzmir, Türkiye.
Ege University, Vaccine Development Application and Research Center, İzmir, Türkiye; Ege University, Faculty of Engineering, Department of Bioengineering, İzmir, Türkiye.
Vaccine. 2024 Oct 24;42(24):126065. doi: 10.1016/j.vaccine.2024.06.032. Epub 2024 Jun 16.
Toxoplasma gondii is an obligate intracellular parasite that can infect a variety of mammals including humans and causes toxoplasmosis. Unfortunately, a protective and safe vaccine against toxoplasmosis hasn't been developed yet. In this study, we developed a DNA vaccine encoding the SRS13 protein and immunized BALB/c mice thrice with pVAX1-SRS13 through the intramuscular route (IM) or intradermally using an electroporation device (ID + EP). The immunogenicity of pVAX1-SRS13 was analyzed by ELISA, Western blot, cytokine ELISA, and flow cytometry. The protective efficacy of the pVAX1-SRS13 was investigated by challenging mice orally with T. gondii PRU strain tissue cysts. The results revealed that pVAX1-SRS13 administered through IM or ID + EP routes induced high level of anti-SRS13 IgG antibody responses (P = 0.0037 and P < 0.0001). The IFN-γ level elicited by the pVAX1-SRS13 (ID + EP) was significantly higher compared to the control group (P = 0.00159). In mice administered with pVAX1-SRS13 (ID + EP), CD8 cells secreting IFN-γ was significantly higher compared to pVAX1-SRS13 (IM) (P = 0.0035) and the control group (P = 0.0068). Mice vaccinated with the SRS13 DNA vaccine did not induce significant IL-4 level. Moreover, a significant reduction in the number of tissue cysts and the load of T. gondii DNA was detected in brains of mice administered with pVAX1-SRS13 through ID + EP and IM routes compared to controls. In conclusion, the SRS13 DNA vaccine was found to be highly immunogenic and confers strong protection against chronic toxoplasmosis.
刚地弓形虫是一种专性细胞内寄生虫，能够感染包括人类在内的多种哺乳动物，并引起弓形体病。不幸的是，目前还没有针对弓形体病的保护性和安全疫苗。在本研究中，我们构建了一种编码 SRS13 蛋白的 DNA 疫苗，并通过肌肉内途径（IM）或使用电穿孔装置（ID+EP）皮内途径三次免疫 BALB/c 小鼠 pVAX1-SRS13。通过 ELISA、Western blot、细胞因子 ELISA 和流式细胞术分析 pVAX1-SRS13 的免疫原性。通过口服 PRU 株弓形虫组织囊虫攻击小鼠来研究 pVAX1-SRS13 的保护效力。结果表明，通过 IM 或 ID+EP 途径给予 pVAX1-SRS13 可诱导高水平的抗 SRS13 IgG 抗体反应（P=0.0037 和 P<0.0001）。与对照组相比，pVAX1-SRS13（ID+EP）诱导的 IFN-γ 水平显著升高（P=0.00159）。在给予 pVAX1-SRS13（ID+EP）的小鼠中，分泌 IFN-γ 的 CD8 细胞明显高于 pVAX1-SRS13（IM）（P=0.0035）和对照组（P=0.0068）。SRS13 DNA 疫苗接种的小鼠未诱导明显的 IL-4 水平。此外，与对照组相比，通过 ID+EP 和 IM 途径给予 pVAX1-SRS13 的小鼠脑中的组织囊数量和弓形虫 DNA 载量显著减少。综上所述，SRS13 DNA 疫苗具有高度的免疫原性，并对慢性弓形体病提供了强大的保护作用。
