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Updated: Jun 17, 2026
Intracranial Subarachnoidal Route of Infection for Investigating Roles of Streptococcus suis Biofilms in Meningitis in a Mouse Infection Model
Published on: July 1, 2018
Immunoprotective activities of a Streptococcus suis pilus subunit in murine models of infection
Manuela Garibaldi1, Manuel J Rodríguez-Ortega, Francesca Mandanici
1The Elie Metchnikoff Department, University of Messina, Messina I-98125, Italy.
Abstract:
Pili of gram-positive bacteria are key virulence factors and their subunits are considered excellent vaccine candidates. Streptococcus suis is an emerging zoonotic agent that can cause epidemics of life-threatening infections in humans, but the functional role or immunoprotective potential of its pilus components have not been studied yet. Using a selective proteomics approach, we have identified a surface protein of serotype 2 S. suis showing features of an ancillary pilus subunit, as evidenced by bioinformatics analysis, immunoblot and immunoelectron microscopy. Immunization with recombinant fragments of this protein, designated herein as PAPI-2b, markedly protected mice from systemic S. suis infection.
Insights
Researchers identified a novel pilus protein, PAPI-2b, in Streptococcus suis. Immunizing mice with this protein fragment significantly protected them against S. suis infection, highlighting its vaccine potential.
Area of Science:
- Microbiology
- Bacteriology
- Vaccinology
Background:
- Gram-positive bacterial pili are crucial virulence factors and potential vaccine targets.
- Streptococcus suis is an emerging zoonotic pathogen causing severe human infections.
- The role and immunoprotective capacity of S. suis pilus components remain unexplored.
Purpose of the Study:
- To identify and characterize novel pilus components of Streptococcus suis serotype 2.
- To evaluate the immunoprotective potential of a newly identified pilus protein against S. suis infection.
Main Methods:
- Selective proteomics was employed to identify surface proteins.
- Bioinformatics analysis, immunoblotting, and immunoelectron microscopy were used for characterization.
- Mice were immunized with recombinant protein fragments (PAPI-2b) and challenged with S. suis.
Main Results:
- A novel surface protein with ancillary pilus subunit characteristics was identified and named PAPI-2b.
- Bioinformatics, immunoblot, and immunoelectron microscopy confirmed its pilus-associated nature.
- Immunization with PAPI-2b fragments conferred significant protection against systemic S. suis infection in mice.
Conclusions:
- PAPI-2b is a surface protein of Streptococcus suis serotype 2 with pilus-associated features.
- PAPI-2b demonstrates significant immunoprotective potential, making it a promising vaccine candidate against S. suis infections.
