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Protection against streptococcal pharyngeal colonization with a vaccinia: M protein recombinant
V A Fischetti1, W M Hodges, D E Hruby
1Rockefeller University, New York, NY 10021.
Abstract:
Phagocytosis of group A streptococci requires type-specific antibodies directed against the variable determinants of the bacterial surface M protein molecule. As a step toward developing a broadly protective anti-streptococcal vaccine, a vaccinia virus (VV) recombinant was constructed that expresses the conserved region of the structural gene encoding the M6 molecule (VV:M6'). Mice immunized intranasally with the VV:M6' virus showed markedly reduced pharyngeal colonization by streptococci after intranasal and oral challenge with these bacteria. M protein-specific serum immunoglobulin G was significantly elevated in vaccinated animals and absent in controls. A similar approach may prove useful for the identification of protective determinants present on other bacterial and viral pathogens.
Insights
Developing a broadly protective vaccine against group A streptococci, this study engineered a vaccinia virus (VV) recombinant expressing a conserved M protein region. Intranasal immunization in mice reduced bacterial colonization and increased M protein antibodies, suggesting a promising vaccine strategy.
Area of Science:
- Microbiology
- Immunology
- Vaccinology
Background:
- Phagocytosis of group A streptococci is hindered by type-specific antibodies targeting variable M protein determinants.
- Developing a broadly protective vaccine against Streptococcus requires targeting conserved regions of the M protein.
Purpose of the Study:
- To construct a vaccinia virus (VV) recombinant expressing the conserved region of the M6 protein (VV:M6').
- To evaluate the efficacy of intranasal immunization with VV:M6' in reducing streptococcal colonization in mice.
Main Methods:
- Construction of a VV recombinant (VV:M6') expressing the conserved M6 protein region.
- Intranasal immunization of mice with VV:M6'.
- Assessment of pharyngeal colonization by Streptococcus after intranasal and oral challenge.
- Measurement of M protein-specific serum immunoglobulin G levels.
Main Results:
- Mice immunized intranasally with VV:M6' exhibited significantly reduced pharyngeal colonization by Streptococcus.
- Vaccinated mice showed elevated M protein-specific serum immunoglobulin G compared to controls.
- The VV:M6' construct effectively delivered the conserved M protein region for immune stimulation.
Conclusions:
- Intranasal immunization with VV:M6' confers protection against Streptococcus pharyngeal colonization in mice.
- This approach highlights the potential of targeting conserved M protein regions for broad-spectrum anti-streptococcal vaccines.
- The strategy may be applicable to developing vaccines against other bacterial and viral pathogens.