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Cell wall preparation consisting of group A carbohydrate and peptidoglycan moieties from Streptococcus pyogenes
Abstract:
Cell walls from Streptococcus pyogenes strain Sv (Group A, M type 3) were lysed with M1 endo-N-acetylmuramidase, and the group A-specific carbohydrate antigen was purified by Sephadex G-100 gel filtration. The initial eluting antigen (M1gA) peak was assessed for mitogenic and polyclonal lymphocyte-activating properties in murine spleen cell cultures. Good mitogenic responses were induced over a broad dose range (1-100 micrograms) with M1gA in both BALB/c and C3H/HeJ splenic cultures. Similar mitogenic responses were induced in nude (nu/nu) and nu/+ splenic cultures, suggesting that M1gA is a B cell mitogen. The M1gA induced anti-trinitrophenyl, anti-sheep erythrocytes, and anti-horse erythrocytes polyclonal plaque-forming cell responses in splenic cell cultures. Studies with purified splenic B cells and M1gA suggest that the mitogenic responses were indeed thymic independent. These studies clearly indicate that native group A carbohydrate antigen is a B cell mitogen and polyclonal B cell activator.
Insights
The group A carbohydrate antigen from Streptococcus pyogenes acts as a potent B cell mitogen. This antigen stimulates polyclonal lymphocyte activation, indicating its role in immune responses.
Area of Science:
- Immunology
- Microbiology
Background:
- Streptococcus pyogenes is a significant human pathogen.
- B cell activation is crucial for adaptive immunity.
Purpose of the Study:
- To investigate the immunomodulatory properties of the group A-specific carbohydrate antigen from Streptococcus pyogenes.
- To determine if the purified antigen acts as a B cell mitogen and polyclonal activator.
Main Methods:
- Cell walls of Streptococcus pyogenes strain Sv were lysed.
- Group A carbohydrate antigen (M1gA) was purified using Sephadex G-100 gel filtration.
- Mitogenic and polyclonal lymphocyte-activating properties were assessed in murine spleen cell cultures.
Main Results:
- M1gA induced significant mitogenic responses in BALB/c, C3H/HeJ, and nude mouse spleen cells.
- M1gA stimulated polyclonal antibody production against various antigens.
- Responses were observed in thymic-independent B cell cultures, confirming B cell mitogenicity.
Conclusions:
- Native group A carbohydrate antigen from Streptococcus pyogenes is a potent B cell mitogen.
- The antigen acts as a polyclonal B cell activator, influencing immune responses.