Outer membrane vesicles derived from < em > Salmonella < /em > Typhimurium can deliver < em > Shigella flexneri < /em > 2a O-polysaccharide antigen to prevent < em > Shigella flexneri < /em > 2a infection in mice

Appl Environ Microbiol. 2021 Jul 28:AEM0096821. doi: 10.1128/AEM.00968-21. Online ahead of print.ABSTRACTShigellosis has become a serious threat to health in many developing countries due to the severe diarrhea it causes. Shigella flexneri 2a (S. flexneri 2a) is the principal species responsible for this endemic disease. Despite multiple attempts to design a vaccine against shigellosis, no effective vaccine has not yet been developed. Lipopolysaccharide (LPS) is both an essential virulence factor and an antigen protective against Shigella, due to its outer domain, termed O-polysaccharide antigen. In the present study, S. flexneri 2a O-polysaccharide antigen was innovatively bio-synthesized in Salmonella and attached to core-lipid A via the ligase WaaL, with purified outer membrane vesicles (OMVs) utilized as vaccine vectors. Here, we identified the expression of the heterologous O-antigen and have described the isolation, characterization, and immune protection efficiency of the OMV vaccine. Furthermore, the results of animal experiments indicated that immunization of mice with the OMV vaccine both intranasally and intraperitoneally induced significant specific anti-Shigella LPS antibodies in the serum, with a similar trend IgA levels from vaginal secretions and fluid from bronchopulmonary lavage. The OMV vaccine derived from both routes of administration provided significant protection against virulent S. flexneri 2a infection, as judged by a serum bactericidal assay (SBA), ...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Source Type: research