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Journal of Immunology Research
Volume 2017, Article ID 7931982, 8 pages
https://doi.org/10.1155/2017/7931982
Research Article

Potential Usefulness of Streptococcus pneumoniae Extracellular Membrane Vesicles as Antibacterial Vaccines

1Division of Bioconvergence Analysis, Korea Basic Science Institute, Daejeon, Republic of Korea
2Tunneling Nanotube Research Center, Division of Life Science, Korea University, Seoul 02841, Republic of Korea
3Department of Bio-Analytical Science, University of Science and Technology, Daejeon, Republic of Korea
4Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
5Department of Functional Genomics, University of Science and Technology, Daejeon, Republic of Korea

Correspondence should be addressed to Seung Il Kim; rk.er.isbk@isk and Gun-Hwa Kim; rk.er.isbk@hgkeneg

Received 30 September 2016; Revised 24 November 2016; Accepted 21 December 2016; Published 22 January 2017

Academic Editor: Giuseppe A. Sautto

Copyright © 2017 Chi-Won Choi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The secretion of extracellular membrane vesicles (EMVs) is a common phenomenon that occurs in archaea, bacteria, and mammalian cells. The EMVs of bacteria play important roles in their virulence, biogenesis mechanisms, and host cell interactions. Bacterial EMVs have recently become the focus of attention because of their potential as highly effective vaccines that cause few side effects. Here, we isolated the EMVs of Streptococcus pneumoniae and examined their potential as new vaccine candidates. Although the S. pneumoniae bacteria were highly pathogenic in a mouse model, the EMVs purified from these bacteria showed low pathological activity both in cell culture and in mice. When mice were injected intraperitoneally with S. pneumoniae EMVs and then challenged, they were protected from both the homologous strain and another pathogenic serotype of S. pneumoniae. We also identified a number of proteins that may have immunogenic activity and may be responsible for the immune responses by the hosts. These results suggest that S. pneumoniae EMVs or their individual immunogenic antigens may be useful as new vaccine agents.