Lin Zhijie, Tang Peipei, Jiao Yang, Kang Xilong, Li Qiuchun, Xu Xiulong, Sun Jun, Pan Zhiming, Jiao Xinan
Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, MOA Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOE Joint International Research Laboratory of Agriculture and Agri-product Safety, Yangzhou University, Yangzhou, 225001, China.
Center for Comparative Medicine, Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225001, China.
BMC Vet Res. 2017 Jun 24;13(1):194. doi: 10.1186/s12917-017-1115-3.
Salmonella enterica serovar Enteritidis (S. Enteritidis) is a highly adaptive pathogen in both humans and animals. As a Salmonella Type III secretion system (T3SS) effector, Salmonella protein tyrosine phosphatase (SptP) is critical for virulence in this genus. To investigate the feasibility of using C50336ΔsptP as a live attenuated oral vaccine in mice, we generated the sptP gene deletion mutant C50336ΔsptP in S. Enteritidis strain C50336 by λ-Red mediated recombination and evaluated the protective ability of the S. Enteritidis sptP mutant strain C50336ΔsptP against mice salmonellosis.
We found that C50336ΔsptP was a highly immunogenic, effective, and safe vaccine in mice. Compared to wild-type C50336, C50336ΔsptP showed reduced virulence as confirmed by the 50% lethal dose (LD) in orally infected mice. C50336ΔsptP also showed decreased bacterial colonization both in vivo and in vitro. Immunization with C50336ΔsptP had no significant effect on body weight and did not result in obvious clinical symptoms relative to control animals treated with phosphate-buffered saline (PBS), but induced humoral and cellular immune responses at 12 and 26 days post inoculation. Immunization with 1 × 10 colony-forming units (CFU) C50336ΔsptP per mouse provided 100% protection against subsequent challenge with the wild-type C50336 strain, and immunized mice showed mild and temporary clinical symptoms as compared to those of control group.
These results demonstrate that C50336ΔsptP can be a live attenuated oral vaccine for salmonellosis.
肠炎沙门氏菌肠炎血清型（肠炎沙门氏菌）是一种在人类和动物中具有高度适应性的病原体。作为沙门氏菌III型分泌系统（T3SS）效应蛋白，沙门氏菌蛋白酪氨酸磷酸酶（SptP）对该属细菌的毒力至关重要。为了研究使用C50336ΔsptP作为小鼠减毒活口服疫苗的可行性，我们通过λ-Red介导的重组在肠炎沙门氏菌菌株C50336中构建了sptP基因缺失突变体C50336ΔsptP，并评估了肠炎沙门氏菌sptP突变株C50336ΔsptP对小鼠沙门氏菌病的保护能力。
我们发现C50336ΔsptP在小鼠中是一种高度免疫原性、有效且安全的疫苗。与野生型C50336相比，经口服感染小鼠的50%致死剂量（LD）证实，C50336ΔsptP的毒力降低。C50336ΔsptP在体内和体外的细菌定植也有所减少。用C50336ΔsptP免疫对体重没有显著影响，相对于用磷酸盐缓冲盐水（PBS）处理的对照动物，也没有导致明显的临床症状，但在接种后12天和26天诱导了体液和细胞免疫反应。每只小鼠用1×10集落形成单位（CFU）的C50336ΔsptP免疫可提供100%的保护，使其免受随后野生型C50336菌株的攻击，与对照组相比，免疫小鼠表现出轻微和短暂的临床症状。
这些结果表明，C50336ΔsptP可以作为一种用于沙门氏菌病的减毒活口服疫苗。
