College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, 54596, Iksan, Republic of Korea.
College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, 54596, Iksan, Republic of Korea.
Vet Microbiol. 2020 Apr;243:108633. doi: 10.1016/j.vetmic.2020.108633. Epub 2020 Mar 2.
Salmonella Enteritidis (SE) is one of the most common culprits of foodborne disease in humans due to its horizontal transmission from infected animals to humans. The development of a safe vaccine against Salmonella would be important for both farm animals and humans concerning disease containment. The SE ghosts carrying FliC were genetically constructed using a special ghost plasmid pJHL184 that co-expressed FliC and the phage lysis gene E. These SE ghosts were characterized by ghost generation efficacy by increasing the culture temperature to "42 °C" in the absence of L-arabinose. This temperature change led to an ghost generation with almost complete lysis of the SE host strain in 48 hs. The expression of FliC was confirmed by Western blot analysis. Also, indirect ELISA was used to prove FliC specific antibody generation in immunized mice. The parenteral adjuvant effect of the FliC antigen was demonstrated by immunizing mice with pJHL184::flC, pJHL184 alone, or PBS alone. The mice were intramuscularly immunized at six weeks of age (n = 8) and boosted after three weeks of primary inoculation. A total of 32 mice were equally divided into four groups. Each group was treated with pJHL-ghosts alone, ghost surface displaying FliC adjuvant, and compared to the PBS and naïve control groups. The immunized mice demonstrated greater IgG and IgA antibody responses than did the PBS control group. Furthermore, the addition of the ghosts to the FliC led to a significant increase in both the humoral and cell-mediated immune responses compared to those in the ghost alone group. Besides, the in vitro antigen uptake and presentation studies revealed efficient antigen presentation on the mouse macrophage cell surfaces. This finding further corroborated the potential efficacy of immune stimulation by SE ghosts. After the virulent challenge, we observed a significant reduction in the bacterial load in the spleen and liver tissues in SE ghosts surface, displaying FliC adjuvant. Our results demonstrate a safe and effective strategy to prevent salmonellosis. They also suggest that the surface expression of flagellin (FliC) significantly enhances antigen-specific humoral and cell-mediated immune responses. This FliC expression can also enhance the protective efficacy of the bacterial ghosts-based vaccine against virulent challenge.
肠炎沙门氏菌（SE）是人类食源性疾病最常见的罪魁祸首之一，因为它可以通过感染动物横向传播给人类。针对沙门氏菌开发安全疫苗对于农场动物和人类控制疾病都很重要。使用特殊的幽灵质粒 pJHL184 构建了携带 FliC 的 SE 幽灵，该质粒共表达 FliC 和噬菌体裂解基因 E。通过将培养温度升高到“42°C”，在没有 L-阿拉伯糖的情况下，这些 SE 幽灵的幽灵生成效率得到了提高，从而实现了这一特性。这种温度变化导致 SE 宿主菌株在 48 小时内几乎完全裂解。通过 Western blot 分析证实了 FliC 的表达。此外，间接 ELISA 用于证明免疫小鼠中 FliC 特异性抗体的产生。通过用 pJHL184::flC、pJHL184 单独或 PBS 单独免疫小鼠，证明了 FliC 抗原的全身佐剂效应。6 周龄（n = 8）时对小鼠进行肌肉内免疫，并在初次接种后 3 周进行加强。总共 32 只小鼠被平均分为四组。每组分别用单独的 JHL-幽灵、表面显示 FliC 佐剂的幽灵以及 PBS 和空白对照组进行处理。与 PBS 对照组相比，免疫小鼠显示出更高的 IgG 和 IgA 抗体反应。此外，与单独使用幽灵相比，添加幽灵导致体液和细胞介导的免疫反应均显著增加。此外，体外抗原摄取和呈递研究表明，在鼠巨噬细胞表面上有效呈递抗原。这一发现进一步证实了 SE 幽灵免疫刺激的潜在功效。在毒力挑战后，我们观察到在表面显示 FliC 佐剂的 SE 幽灵中，脾脏和肝脏组织中的细菌负荷显著降低。我们的结果证明了一种安全有效的预防沙门氏菌病的策略。它们还表明，鞭毛蛋白（FliC）的表面表达显著增强了抗原特异性体液和细胞介导的免疫反应。这种 FliC 表达还可以增强基于细菌幽灵的疫苗对毒力挑战的保护效力。
