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A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Immunization with a streptococcal multiple-epitope recombinant protein protects mice against invasive group A
Chih-Feng Kuo1, Nina Tsao2, I-Chen Hsieh2
1Department of Nursing, College of Medicine, I-Shou University, Kaohsiung, Taiwan.
Abstract:
Streptococcus pyogenes (group A Streptococcus; GAS) causes clinical diseases, including pharyngitis, scarlet fever, impetigo, necrotizing fasciitis and streptococcal toxic shock syndrome. A number of group A streptococcus vaccine candidates have been developed, but only one 26-valent recombinant M protein vaccine has entered clinical trials. Differing from the design of a 26-valent recombinant M protein vaccine, we provide here a vaccination using the polyvalence epitope recombinant FSBM protein (rFSBM), which contains four different epitopes, including the fibronectin-binding repeats domain of streptococcal fibronectin binding protein Sfb1, the C-terminal immunogenic segment of streptolysin S, the C3-binding motif of streptococcal pyrogenic exotoxin B, and the C-terminal conserved segment of M protein. Vaccination with the rFSBM protein successfully prevented mortality and skin lesions caused by several emm strains of GAS infection. Anti-FSBM antibodies collected from the rFSBM-immunized mice were able to opsonize at least six emm strains and can neutralize the hemolytic activity of streptolysin S. Furthermore, the internalization of GAS into nonphagocytic cells is also reduced by anti-FSBM serum. These findings suggest that rFSBM can be applied as a vaccine candidate to prevent different emm strains of GAS infection.
Insights
A novel polyvalent epitope recombinant FSBM protein (rFSBM) vaccine candidate effectively prevented mortality and skin lesions in Group A Streptococcus infections. Antibodies generated by rFSBM vaccination demonstrated broad opsonization and neutralization capabilities against multiple GAS strains.
Area of Science:
- Microbiology
- Immunology
- Vaccine Development
Background:
- Streptococcus pyogenes (Group A Streptococcus; GAS) is a significant human pathogen responsible for various infections, ranging from pharyngitis to severe conditions like necrotizing fasciitis and toxic shock syndrome.
- Current vaccine development for GAS has primarily focused on M protein-based strategies, with limited candidates progressing to clinical trials.
Purpose of the Study:
- To evaluate a novel polyvalent epitope recombinant FSBM protein (rFSBM) as a potential vaccine candidate against diverse strains of Group A Streptococcus.
- To assess the efficacy of rFSBM vaccination in preventing GAS-induced mortality and skin lesions and its ability to elicit protective immune responses.
Main Methods:
- Development of a recombinant FSBM protein incorporating four distinct GAS epitopes: Sfb1 fibronectin-binding repeats, streptolysin S C-terminus, streptococcal pyrogenic exotoxin B C3-binding motif, and M protein C-terminus.
- Vaccination of mice with rFSBM and subsequent challenge with various emm strains of GAS.
- Assessment of anti-FSBM antibody functionality, including opsonization of GAS strains, neutralization of streptolysin S hemolytic activity, and reduction of GAS internalization into nonphagocytic cells.
Main Results:
- Vaccination with rFSBM protein conferred significant protection against mortality and skin lesions caused by multiple emm strains of GAS infection.
- Anti-FSBM antibodies exhibited broad opsonizing activity against at least six different emm strains.
- The generated antibodies effectively neutralized the hemolytic activity of streptolysin S and reduced GAS internalization into host cells.
Conclusions:
- The rFSBM protein represents a promising vaccine candidate for preventing infections caused by a wide range of Group A Streptococcus strains.
- The polyvalent nature of the rFSBM vaccine contributes to its broad-spectrum efficacy by targeting multiple virulence factors and conserved regions of GAS.
