肠炎沙门氏菌是引起全球人类感染的最普遍的血清型。食用肠炎沙门氏菌污染的动物性食品是人类感染的主要来源;然而,从动物中根除细菌仍然很困难。因此,有必要制定新的措施来预防和控制沙门氏菌病。这里,我们使用肠炎沙门氏菌的外膜囊泡(OMV),并评估其在小鼠中的保护功效和免疫反应。与野生型(WT)和ΔrfaQ菌株相比,在肠炎沙门氏菌中删除tolR会增加OMV的产量和大小。用OMV进行的肌内免疫比腹膜内和鼻内免疫具有更大的保护作用。此外,从WT和ΔtolR菌株中提取的OMV在用肠炎沙门氏菌攻击的小鼠中提供了83.3%的保护率,高于从ΔrfaQ菌株提取的OMV提供的值。然而,与来自ΔtolR菌株的OMV相比,来自WT和ΔrfaQ菌株的OMV迅速根除了在肝脏定植的肠炎链球菌,脾,脾回肠,免疫后BALB/c小鼠盲肠。用来自三个菌株中的每一个的OMV免疫诱导体液免疫应答并且显示对小鼠的生长没有副作用。我们的研究表明,来自各种肠炎沙门氏菌菌株的OMV可以被开发用作抗哺乳动物非伤寒沙门氏菌感染的亚单位疫苗候选物。
Salmonella enterica serovar Enteritidis is the most prevalent serotype that causes human infections worldwide. Consumption of S. Enteritidis-contaminated animal foods is a major source of human infections; however, eradicating bacteria from animals remains difficult. Therefore, it is necessary to develop new measures to prevent and control salmonellosis. Here, we used the outer-membrane vesicles (OMVs) of S. Enteritidis and assessed their protective efficacy and immune response in mice. Deletion of tolR in S. Enteritidis increased the production and size of OMVs compared to those in the wild type (WT) and ΔrfaQ strains. Intramuscular immunization with OMVs conferred greater protection than intraperitoneal and intranasal immunization. Moreover, OMVs extracted from both WT and ΔtolR strains provided an 83.3% protective rate in mice challenged with S. Enteritidis, which was higher than that provided by OMVs extracted from the ΔrfaQ strain. However, compared with OMVs from the ΔtolR strain, OMVs from WT and ΔrfaQ strains rapidly eradicated S. Enteritidis colonizing the liver, spleen, ileum, and cecum of BALB/c mice after immunization. Immunization with OMVs from each of the three strains induced humoral immune responses and showed no side effects on the growth of mice. Our study revealed that OMVs from various S. Enteritidis strains could be developed for use as subunit vaccine candidates against nontyphoidal Salmonella infections in mammals.