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Published on: December 8, 2023
Potential Usefulness of Streptococcus pneumoniae Extracellular Membrane Vesicles as Antibacterial Vaccines
Chi-Won Choi1, Edmond Changkyun Park2, Sung Ho Yun3
1Division of Bioconvergence Analysis, Korea Basic Science Institute, Daejeon, Republic of Korea; Tunneling Nanotube Research Center, Division of Life Science, Korea University, Seoul 02841, Republic of Korea.
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.
Insights
Extracellular membrane vesicles (EMVs) from Streptococcus pneumoniae show low pathogenicity and protect mice against infection. These bacterial EMVs show promise as novel vaccine candidates against pneumococcal disease.
Area of Science:
- Microbiology
- Immunology
- Vaccinology
Background:
- Extracellular membrane vesicles (EMVs) are secreted by various organisms, including bacteria.
- Bacterial EMVs are implicated in virulence and host interactions, and are emerging as potential vaccine platforms.
- Streptococcus pneumoniae is a major human pathogen, necessitating effective vaccine strategies.
Purpose of the Study:
- To investigate the vaccine potential of EMVs derived from Streptococcus pneumoniae.
- To assess the pathogenicity and immunogenicity of S. pneumoniae EMVs.
- To identify potential immunogenic antigens within S. pneumoniae EMVs.
Main Methods:
- Isolation and purification of EMVs from Streptococcus pneumoniae.
- Evaluation of EMV pathogenicity in cell culture and a mouse model.
- Assessment of protective immunity in mice following EMV vaccination and subsequent challenge with S. pneumoniae.
- Proteomic analysis to identify immunogenic proteins.
Main Results:
- Purified S. pneumoniae EMVs exhibited low pathogenicity in vitro and in vivo.
- Mice vaccinated with S. pneumoniae EMVs demonstrated protection against homologous and heterologous S. pneumoniae serotypes.
- Several proteins with potential immunogenic activity were identified in the EMVs.
- EMVs induced protective immune responses against S. pneumoniae infection.
Conclusions:
- Streptococcus pneumoniae EMVs are a promising candidate for developing new vaccines.
- S. pneumoniae EMVs offer a safe alternative to whole-cell vaccines, with low observed pathogenicity.
- Individual immunogenic antigens from S. pneumoniae EMVs could also serve as vaccine components.
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