College of Animal Science and Technology, Shihezi University, Shihezi 832003, China.
Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130122, China.
Viruses. 2022 Jul 28;14(8):1664. doi: 10.3390/v14081664.
The Crimean Congo Hemorrhagic Fever Virus (CCHFV) is a tick-borne bunyavirus of the Narovirus genus, which is the causative agent of Crimean Congo Hemorrhagic Fever (CCHF). CCHF is endemic in Africa, the Middle East, Eastern Europe and Asia, with a high case-fatality rate of up to 50% in humans. Currently, there are no approved vaccines or effective therapies available for CCHF. The GEM-PA is a safe, versatile and effective carrier system, which offers a cost-efficient, high-throughput platform for recovery and purification of subunit proteins for vaccines. In the present study, based on a GEM-PA surface display system, a GEM-PA based vaccine expressing three subunit vaccine candidates (G-GP, including G-eG, G-eG and G-NAb) of CCHFV was developed, displaying the ectodomains of the structural glycoproteins eG, eG and NAb, respectively. According to the immunological assays including indirect-ELISA, a micro-neutralization test of pseudo-virus and ELISpot, 5 μg GPBLP combined with Montanide ISA 201VG plus Poly (I:C) adjuvant (A-G-GP-5 μg) elicited GP-specific humoral and cellular immunity in BALB/c mice after three vaccinations via subcutaneous injection (s.c.). The consistent data between IgG subtype and cytokine detection, ELISpot and cytokine detection indicated balanced Th1 and Th2 responses, of which G-eG vaccines could elicit a stronger T-cell response post-vaccination, respectively. Moreover, all three vaccine candidates elicited high TNF-α, IL-6, and IL-10 cytokine levels in the supernatant of stimulated splenocytes in vitro. However, the neutralizing antibody (nAb) was only detected in A-G-eG and A-G-eG vaccination groups with the highest neutralizing titer of 128, suggesting that G-eG could elicit a stronger humoral immune response. In conclusion, the GEM-PA surface display system could provide an efficient and convenient purification method for CCHFV subunit antigens, and the G-GP subunit vaccine candidates will be promising against CCHFV infections with excellent immunogenicity.
克里米亚-刚果出血热病毒（CCHFV）是一种属于诺罗病毒属的蜱传布尼亚病毒，是克里米亚-刚果出血热（CCHF）的病原体。CCHF 在地中海地区、中东、东欧和亚洲流行，其人类病死率高达 50%。目前，尚无批准用于治疗 CCHF 的疫苗或有效疗法。GEM-PA 是一种安全、多功能且有效的载体系统，为亚单位疫苗候选物的回收和纯化提供了一种具有成本效益、高通量的平台。在本研究中，基于 GEM-PA 表面展示系统，构建了一种表达三种 CCHFV 亚单位疫苗候选物（G-GP，包括 G-eG、G-eG 和 G-NAb）的 GEM-PA 疫苗，分别展示了结构糖蛋白 eG、eG 和 NAb 的外显子。根据间接 ELISA、假病毒微量中和试验和 ELISpot 等免疫测定结果，5μg GPBLP 与 Montanide ISA 201VG 佐剂加 Poly（I:C）（A-G-GP-5μg）联合免疫 BALB/c 小鼠 3 次后，通过皮下注射（s.c.）可诱导 GP 特异性体液和细胞免疫。IgG 亚型和细胞因子检测、ELISpot 和细胞因子检测之间的一致数据表明，存在平衡的 Th1 和 Th2 反应，其中 G-eG 疫苗在接种后可诱导更强的 T 细胞反应。此外，所有三种疫苗候选物均可在体外刺激的脾细胞上清液中诱导高水平的 TNF-α、IL-6 和 IL-10 细胞因子。然而，仅在 A-G-eG 和 A-G-eG 免疫组中检测到中和抗体（nAb），且中和滴度最高为 128，表明 G-eG 可诱导更强的体液免疫反应。总之，GEM-PA 表面展示系统可为 CCHFV 亚单位抗原的高效、便捷纯化提供方法，G-GP 亚单位疫苗候选物具有良好的免疫原性，有望用于预防 CCHFV 感染。
