Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China.
Northeast Science Inspection Station, Key Laboratory of Animal Pathogen Biology of Ministry of Agriculture of China, Harbin, P. R. China.
Microb Cell Fact. 2020 Oct 1;19(1):186. doi: 10.1186/s12934-020-01449-3.
Bovine viral diarrhea virus (BVDV) is one of the main causes of infectious diseases in cattle and causes large financial losses to the cattle industry worldwide. In this study, Lactobacillus casei strain W56 (Lc W56) was used as antigen deliver carrier to construct a recombinant Lactobacillus vaccine pPG-E2-ctxB/Lc W56 constitutively expressing BVDV E2 protein fused with cholera toxin B subunit (ctxB) as an adjuvant, and its immunogenicity against BVDV infection in mice model by oral route was explored.
Our results suggested that pPG-E2-ctxB/Lc W56 can effectively activate dendritic cells (DCs) in the Peyer's patches, up-regulate the expression of Bcl-6, and promote T-follicular helper (Tfh) cells differentiation, as well as enhance B lymphocyte proliferation and promote them differentiate into specific IgA-secreting plasma cells, secreting anti-E2 mucosal sIgA antibody with BVDV-neutralizing activity. Moreover, significant levels (p < 0.01) of BVDV-neutralizing antigen-specific serum antibodies were induced in the pPG-E2-ctxB/LC W56 group post-vaccination. The recombinant Lactobacillus vaccine can induce cellular immune responses, and significant levels (p < 0.01) of Th1-associated cytokines (IL-2, IL-12, and IFN-γ), Th2-associated cytokines (IL-4, IL-10) and Th17-associated cytokine (IL-17) were determined in the serum of vaccinated mice. Significantly, the recombinant Lactobacillus vaccine provides immune protection against BVDV infection, which can be cleared effectively by the vaccine post-challenge in orally vaccinated animals.
The genetically engineered Lactobacillus vaccine constructed in this study is immunogenic in mice and can induce mucosal, humoral, and cellular immune responses, providing effective anti-BVDV immune protection. It thus represents a promising strategy for vaccine development against BVDV.
牛病毒性腹泻病毒（BVDV）是引起牛传染性疾病的主要原因之一，给全球养牛业造成了巨大的经济损失。本研究以干酪乳杆菌菌株 W56（Lc W56）为抗原传递载体，构建了一种表达 BVDV E2 蛋白融合霍乱毒素 B 亚单位（ctxB）的重组乳酸杆菌疫苗 pPG-E2-ctxB/Lc W56，作为佐剂，通过口服途径探索其在小鼠模型中对 BVDV 感染的免疫原性。
我们的结果表明，pPG-E2-ctxB/Lc W56 可以有效地激活派氏结中的树突状细胞（DCs），上调 Bcl-6 的表达，促进滤泡辅助性 T 细胞（Tfh）分化，并增强 B 淋巴细胞的增殖，促进其分化为特异性 IgA 分泌浆细胞，分泌具有中和 BVDV 活性的抗 E2 黏膜 sIgA 抗体。此外，pPG-E2-ctxB/Lc W56 组接种后诱导出显著水平（p<0.01）的 BVDV 中和抗原特异性血清抗体。重组乳酸杆菌疫苗可诱导细胞免疫应答，接种小鼠血清中检测到显著水平（p<0.01）的 Th1 相关细胞因子（IL-2、IL-12 和 IFN-γ）、Th2 相关细胞因子（IL-4、IL-10）和 Th17 相关细胞因子（IL-17）。值得注意的是，重组乳酸杆菌疫苗可有效清除口服接种动物的疫苗后挑战，提供针对 BVDV 感染的免疫保护。
本研究构建的遗传工程化乳酸杆菌疫苗在小鼠中具有免疫原性，可诱导黏膜、体液和细胞免疫应答，提供有效的抗 BVDV 免疫保护。因此，它代表了针对 BVDV 疫苗开发的一种有前途的策略。
