Exp Mol Med.  2015 Sep;47(9):e183. 10.1038/emm.2015.59.

Vaccination with Klebsiella pneumoniae-derived extracellular vesicles protects against bacteria-induced lethality via both humoral and cellular immunity

• Lee WH
• Choi HI
• Hong SW
• Kim KS
• Gho YS
• Jeon SG

• KMID: 2155437
• DOI: http://doi.org/10.1038/emm.2015.59

Abstract

The emergence of multidrug-resistant Klebsiella pneumoniae highlights the need to develop preventive measures to ameliorate Klebsiella infections. Bacteria-derived extracellular vesicles (EVs) are spherical nanometer-sized proteolipids enriched with outer membrane proteins. Gram-negative bacteria-derived EVs have gained interest for use as nonliving complex vaccines. In the present study, we evaluated whether K. pneumoniae-derived EVs confer protection against bacteria-induced lethality. K. pneumoniae-derived EVs isolated from in vitro bacterial culture supernatants induced innate immunity, including the upregulation of co-stimulatory molecule expression and proinflammatory mediator production. EV vaccination via the intraperitoneal route elicited EV-reactive antibodies and interferon-gamma-producing T-cell responses. Three vaccinations with the EVs prevented bacteria-induced lethality. As verified by sera and splenocytes adoptive transfer, the protective effect of EV vaccination was dependent on both humoral and cellular immunity. Taken together, these findings suggest that K. pneumoniae-derived EVs are a novel vaccine candidate against K. pneumoniae infections.

MeSH Terms

Animals
Bacterial Vaccines/immunology/*microbiology/*therapeutic use
Extracellular Vesicles/immunology/*microbiology
Female
Humans
Immunity, Cellular
Immunity, Innate
Interferon-gamma/immunology
Klebsiella Infections/immunology/*prevention &control
Klebsiella pneumoniae/*immunology
Mice, Inbred C57BL
Vaccination
Bacterial Vaccines
Interferon-gamma