BACKGROUND Streptococcus suis (SS) is a major swine pathogen and a serious zoonotic pathogen causing septicemia and meningitis in piglets and humans. Using an immunoproteomic approach, we previously brought evidence that ornithine carbamoytransferase (OCT) may represent a vaccine candidate to protect against S. suis biofilm-related and acute infections. METHOD In this study, the gene encoding OCT was cloned into the expression vector pET-28a and the recombinant protein was expressed in Escherichia coli BL21. The immunogenicity and protective efficacy of the SS OCT was further investigated in a mouse model. RESULTS The protein was found to be expressed in vivo and elicited high antibody titers following SS infections in mice. An animal challenge experiment with SS showed that 62.5% of mice immunized with the OCT protein were protected. Using an in vitro competitive adherence inhibition assay of adherence, evidence was obtained that OCT could significantly reduce the number of SS cells adhered to porcine kidney PK-15 cells. The bacterial levels recovered in mice of the OCT immunized group were significantly decreased in some organs, compared with the control group. CONCLUSION In summary, our results suggest that the recombinant SS OCT protein, which is involved in bacterial adherence, may efficiently stimulate an immune response conferring protection against SS infections. It may therefore be considered as a potential vaccine candidate, although further studies are necessary to evaluate their use in swine.

中文翻译：

---

猪链球菌免疫原性鸟氨酸氨基甲酸酯基转移酶参与细菌粘附的鉴定和鉴定。

背景技术猪链球菌（SS）是主要的猪病原体和严重的人畜共患病原体，在仔猪和人类中引起败血病和脑膜炎。使用免疫蛋白质组学方法，我们先前带来的证据表明鸟氨酸氨基甲酸酯基转移酶（OCT）可以代表疫苗来预防猪链球菌生物膜相关和急性感染。方法在本研究中，将编码OCT的基因克隆到表达载体pET-28a中，并在大肠杆菌BL21中表达该重组蛋白。在小鼠模型中进一步研究了SS OCT的免疫原性和保护功效。结果发现该蛋白在小鼠SS感染后在体内表达并引起高抗体滴度。用SS进行的动物攻击实验表明，用OCT蛋白免疫的小鼠中有62.5％受了保护。使用粘附的体外竞争性粘附抑制测定法，获得的证据表明OCT可以显着减少猪肾PK-15细胞粘附的SS细胞的数量。与对照组相比，OCT免疫组小鼠的某些器官中回收的细菌水平明显降低。结论总的来说，我们的结果表明，参与细菌粘附的重组SS OCT蛋白可以有效刺激免疫应答，从而提供针对SS感染的保护作用。因此，尽管有必要进行进一步的研究以评估其在猪中的应用，但仍可将其视为潜在的疫苗候选者。获得的证据表明，OCT可以显着减少猪肾脏PK-15细胞粘附的SS细胞数量。与对照组相比，OCT免疫组小鼠的某些器官中回收的细菌水平明显降低。结论总之，我们的结果表明，参与细菌粘附的重组SS OCT蛋白可以有效刺激免疫应答，从而提供针对SS感染的保护作用。因此，尽管有必要进行进一步的研究以评估其在猪中的应用，但仍可将其视为潜在的疫苗候选者。获得的证据表明，OCT可以显着减少粘附在猪肾PK-15细胞上的SS细胞的数量。与对照组相比，OCT免疫组小鼠的某些器官中回收的细菌水平明显降低。结论总之，我们的结果表明，参与细菌粘附的重组SS OCT蛋白可以有效刺激免疫应答，从而提供针对SS感染的保护作用。因此，尽管有必要进行进一步的研究以评估其在猪中的应用，但仍可将其视为潜在的疫苗候选者。参与细菌粘附的细菌可以有效地刺激免疫反应，从而保护其免受SS感染。因此，尽管有必要进行进一步的研究以评估其在猪中的应用，但仍可将其视为潜在的疫苗候选者。参与细菌粘附的细菌可以有效地刺激免疫反应，从而保护其免受SS感染。因此，尽管有必要进行进一步的研究以评估其在猪中的应用，但仍可将其视为潜在的疫苗候选者。