State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, P.R. China.
Shandong Vocational Animal Science and Veterinary College, Weifang, P.R. China.
J Microbiol Biotechnol. 2022 Mar 28;32(3):278-286. doi: 10.4014/jmb.2107.07052.
Live bacterial vector vaccines are one of the most promising vaccine types and have the advantages of low cost, flexibility, and good safety. Meanwhile, protein secretion systems have been reported as useful tools to facilitate the release of heterologous antigen proteins from bacterial vectors. The twin-arginine translocation (Tat) system is an important protein export system that transports fully folded proteins in a signal peptide-dependent manner. In this study, we constructed a live vector vaccine using an engineered commensal strain in which and genes were deleted, resulting in a leaky outer membrane that allows the release of periplasmic proteins to the extracellular environment. The protective antigen proteins SLY, enolase, and Sbp against were targeted to the Tat pathway by fusing a Tat signal peptide. Our results showed that by exploiting the Tat pathway and the outer membrane-defective strain, the antigen proteins were successfully secreted. The strains secreting the antigen proteins were used to vaccinate mice. After challenge, the vaccinated group showed significantly higher survival and milder clinical symptoms compared with the vector group. Further analysis showed that the mice in the vaccinated group had lower burdens of bacteria load and slighter pathological changes. Our study reports a novel live bacterial vector vaccine that uses the Tat system and provides a new alternative for developing vaccine.
活细菌载体疫苗是最有前途的疫苗类型之一，具有成本低、灵活性好、安全性好的优点。同时，蛋白分泌系统已被报道为促进异源抗原蛋白从细菌载体释放的有用工具。双精氨酸易位（Tat）系统是一种重要的蛋白输出系统，以信号肽依赖的方式转运完全折叠的蛋白。在本研究中，我们构建了一种利用工程共生 菌株的活载体疫苗，该菌株缺失了 和 基因，导致外膜渗漏，允许周质蛋白释放到细胞外环境中。针对 ，保护性抗原蛋白 SLY、烯醇酶和 Sbp 被融合 Tat 信号肽靶向 Tat 途径。我们的结果表明，通过利用 Tat 途径和外膜缺陷型 菌株，抗原蛋白成功地被分泌。分泌抗原蛋白的菌株被用于免疫小鼠。在 挑战后，与载体组相比，接种组的小鼠存活率显著提高，临床症状较轻。进一步分析表明，接种组小鼠的细菌负荷较低，病理变化较轻。本研究报告了一种利用 Tat 系统的新型活细菌载体疫苗，为开发 疫苗提供了新的选择。
