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.
|Journal||Experimental and Molecular Medicine|
|Publication status||Published - 2015|
Bibliographical noteFunding Information:
We thank members of the animal facility in Pohang University of Science and Technology Biotech Center (Pohang University of Science and Technology, Pohang, Republic of Korea) for their valuable technical assistance. This study was supported by grants from the Korea Ministry of Health & Welfare, Republic of Korea (HI14C-2694-010014) and from KRIBB initiative programs.
© 2015 KSBMB. All rights reserved.
All Science Journal Classification (ASJC) codes
- Molecular Medicine
- Molecular Biology
- Clinical Biochemistry