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Sublingual Immunotherapy as an Alternative to Induce Protection Against Acute Respiratory Infections
Published on: August 30, 2014
Intranasal immunization with serum opacity factor (SOF) of Streptococcus pyogenes fails to protect mice against
Kai Schulze1, Eva Medina, Carlos A Guzmán
1Department of Microbial Pathogenesis and Vaccine Research, Division of Microbiology, GBF-German Research Centre for Biotechnology, D-38124 Braunschweig, Germany.
Abstract:
Streptococcus pyogenes is a human pathogen causing invasive and non-invasive diseases, as well as severe sequels, such as rheumatic fever. Several bacterial factors have been proposed as candidate vaccine antigens. Among them, the serum opacity factor (SOF), which was able to confer protective immunity against an intraperitoneal challenge after vaccination by the parenteral route. In an attempt to develop more efficient vaccines, we combined SOF with an additional well-known protective antigen, namely, the fibronectin-binding protein I (SfbI). Intranasal immunization of mice with SOF and SfbI stimulates strong systemic and mucosal immune responses against both antigens. Animals vaccinated with SfbI, alone or in combination with SOF, were also efficiently protected against a lethal challenge with a SOF/SfbI-positive virulent S. pyogenes strain (80% survival). In contrast, those vaccinated with SOF alone were not protected against a mucosal challenge (100% lethality), which mimics more closely natural infections. These results highlight the importance of developing adequate experimental animal models to evaluate vaccine efficiency, according to the selected antigen.
Insights
Developing new vaccines against Streptococcus pyogenes requires effective antigen combinations. Combining serum opacity factor (SOF) and fibronectin-binding protein I (SfbI) showed promising protection in mice against virulent strains.
Area of Science:
- Microbiology and Immunology
- Vaccine Development
- Bacterial Pathogenesis
Background:
- Streptococcus pyogenes is a significant human pathogen responsible for various infections and sequelae like rheumatic fever.
- Candidate vaccine antigens, including serum opacity factor (SOF) and fibronectin-binding protein I (SfbI), have been investigated for their protective potential.
- Previous studies indicated SOF confers protection via parenteral vaccination against intraperitoneal challenge.
Purpose of the Study:
- To develop more effective Streptococcus pyogenes vaccines by combining SOF and SfbI.
- To evaluate the systemic and mucosal immune responses elicited by intranasal immunization with SOF and SfbI.
- To assess the protective efficacy of SOF and SfbI, individually and in combination, against a virulent S. pyogenes strain.
Main Methods:
- Intranasal immunization of mice with SOF and SfbI, alone and in combination.
- Assessment of systemic and mucosal immune responses against both antigens.
- Evaluation of vaccine efficacy through lethal challenge with a virulent SOF/SfbI-positive S. pyogenes strain.
Main Results:
- Intranasal vaccination with SOF and SfbI stimulated robust systemic and mucosal immunity against both antigens.
- Mice vaccinated with SfbI (alone or with SOF) demonstrated significant protection (80% survival) against a lethal S. pyogenes challenge.
- Vaccination with SOF alone did not provide protection against a mucosal challenge, resulting in 100% lethality.
Conclusions:
- Combining SfbI with SOF enhances protective immunity against Streptococcus pyogenes, particularly when administered intranasally.
- The efficacy of vaccine candidates should be evaluated using experimental models that mimic natural infection routes, such as mucosal challenge.
- SfbI appears to be a more critical antigen than SOF for protection against virulent S. pyogenes, especially via mucosal routes.
