Multi-serotype outer membrane vesicles of Shigellae confer passive protection to the neonatal mice against shigellosis

Recently, we have demonstrated, immunization of adult female mice with outer membrane vesicles (OMVs) of Shigella boydii type 4 protected their offspring passively from shigellosis. In our present study, we have advanced our research by formulating multi-serotype outer membrane vesicles (MOMVs), mixing the OMVs of Shigella dysenteriae 1 Δstx, Shigella flexneri 2a, 3a and 6, S. boydii type 4 and Shigella sonnei to achieve a broad spectrum protection against shigellosis. Adult mice were immunized orally with 50 μg of MOMVs, four times at weekly intervals. Immunological parameters were observed at various time points, before, during and after immunization, in adult mice. Passive protection was examined in their offspring by measuring protective efficacy and studying intestinal colonization, after challenging with various Shigella strains. Immunized dams exhibited a consistent broad spectrum antibody response. 3–4 day-old offspring of immunized dams showed significant long term passive protection against wild type S. flexneri 2a, 3a, and 6, S. boydii type 2 and S. dysenteriae 1. Their stomach extracts, essentially containing mother's milk, have also exhibited significant levels of anti-MOMVs immunoglobulins. In conclusion, MOMVs formulation represents an easy, safe immunization strategy that was found suitable to provide complete passive protection to the neonatal mice against all four serogroups of Shigellae. It could be exploited for the development of a novel non-living vaccine against human shigellosis in near future.     

PFGE法分析多血清型副溶血性弧菌引起的食物中毒

目的:对从食物中毒样品中分离到的7株副溶血性弧菌作常规鉴定及脉冲场凝胶电泳(PFGE)同源性分析,以明确致病因子。方法:按GB/T4789.7-2008进行副溶血性弧菌分离、生化鉴定、神奈川试验、血清分型;Pulse-Net PFGE分子分型标准实验室操作方法作同源性分析。结果:7株副溶血性弧菌分成三个血清型,即O3∶K6型5株,O4∶K8型和O1∶K56型各1株,分别属于三种不同的PFGE条带型,其中6株菌神奈川试验阳性。结论:这次食物中毒可能为以O3∶K6型为主的不同克隆群副溶血性弧菌混合感染所致。