Huang Xia, Kang Xilong, Han Shunzi, Meng Chuang, Song Hongqin, Jiao Xinan, Pan Zhiming
Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, Jiangsu 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu 225009, China; Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou, Jiangsu 225009, China.
Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu 225009, China.
Vet Immunol Immunopathol. 2025 Jan;279:110864. doi: 10.1016/j.vetimm.2024.110864. Epub 2024 Dec 10.
African swine fever (ASF) is a transmissible and deadly viral disease caused by the African swine fever virus (ASFV) that has considerably affected the global pig industry. Vaccination is considered a potentially effective method to control ASF. However, live attenuated vaccines can't protect against all circulating virus isolates. Subunit vaccines can induce both cellular and humoral immune responses, but often require the addition of adjuvants. Flagellin, a stimulator of Toll-like receptor 5 (TLR5), functions as a potent adjuvant by enhancing cellular and humoral immune responses. However, its high antigenicity may cause severe systemic inflammation. In this study, an Escherichia coli expression system was used to express ASFV p30 protein (p30) fused with Salmonella Typhimurium FliCΔD2D3 (without the D2 and D3 domains of FliC). The immunological effect of p30-FlicΔD2D3 protein in mice was evaluated. Results revealed that the ASFV p30 protein and the p30-FlicΔD2D3 fusion protein were effectively expressed by the E. coli expression system. In vitro activity analysis showed that the p30-FlicΔD2D3 fusion protein could be recognized by ASFV-positive serum, had good immunoreactivity, and remarkably promoted IL-8 secretion related to TLR5 activity in HEK293-mTLR5 cells. However, p30-FlicΔD2D3 induced significantly lower levels of inflammatory factor IL-8 than that induced by wild-type flagellin. Immunization with the p30-FlicΔD2D3 fusion protein considerably promoted cellular and humoral immune responses in mice. Therefore, the p30-FlicΔD2D3 protein retained good immune reactivity and TLR5 agonist efficacy. It also enhanced humoral and cellular immune responses in mice. This work offered valuable information that will be helpful to develop ASF subunit vaccines.
非洲猪瘟（ASF）是一种由非洲猪瘟病毒（ASFV）引起的具有传染性的致命病毒性疾病，已对全球养猪业造成了重大影响。疫苗接种被认为是控制ASF的一种潜在有效方法。然而，减毒活疫苗无法抵御所有流行的病毒毒株。亚单位疫苗可诱导细胞免疫和体液免疫反应，但通常需要添加佐剂。鞭毛蛋白是Toll样受体5（TLR5）的刺激物，通过增强细胞免疫和体液免疫反应发挥强效佐剂的作用。然而，其高抗原性可能会导致严重的全身炎症。在本研究中，利用大肠杆菌表达系统表达与鼠伤寒沙门氏菌FliCΔD2D3（无FliC的D2和D3结构域）融合的ASFV p30蛋白（p30）。评估了p30-FlicΔD2D3蛋白在小鼠体内的免疫效果。结果显示，大肠杆菌表达系统有效表达了ASFV p30蛋白和p30-FlicΔD2D3融合蛋白。体外活性分析表明，p30-FlicΔD2D3融合蛋白可被ASFV阳性血清识别，具有良好的免疫反应性，并能显著促进HEK293-mTLR5细胞中与TLR5活性相关的IL-8分泌。然而，p30-FlicΔD2D3诱导的炎症因子IL-8水平明显低于野生型鞭毛蛋白诱导的水平。用p30-FlicΔD2D3融合蛋白免疫可显著促进小鼠的细胞免疫和体液免疫反应。因此，p30-FlicΔD2D3蛋白保留了良好的免疫反应性和TLR5激动剂功效。它还增强了小鼠的体液免疫和细胞免疫反应。这项工作提供了有价值的信息，将有助于开发ASF亚单位疫苗。
