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Enhanced resistance to streptococcal infection induced in mice by cell wall mucopeptide
Abstract:
The streptococcal cell wall mucopeptide when injected into mice either intraperitoneally or intravenously enhances the resitance to subsequent challenge with virulent Group A streptococci. Rabbits which are injected intravenously with solubilized mucopeptide develop a fever response which has a resemblance to that achieved with endotoxin. Mice which survive 6 to 7 weeks after challenge with virulent Group A streptococci yield at autopsy search Group A streptococci serologically identical to the challenge organisms. A preparative dose of cell walls injected into mice prior to challenge diminished this late recovery of streptococci. Group A-variant streptococci were recovered from mice which survived challenge and carried the organisms for several weeks. Filterable bacterial forms, which grew on L form media, were recovered from infected mice. The serologic type of the L forms was identical to that of the challenge organisms.
Insights
Injecting streptococcal cell wall mucopeptide enhances resistance to Group A streptococci infection in mice. This treatment also reduced late-stage bacterial recovery and identified novel filterable bacterial forms.
Area of Science:
- Microbiology
- Immunology
- Bacterial Pathogenesis
Background:
- The streptococcal cell wall contains components that can modulate host immune responses.
- Understanding the interaction between streptococcal antigens and host defense mechanisms is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the immunomodulatory effects of streptococcal cell wall mucopeptide.
- To assess the impact of mucopeptide administration on resistance to Group A streptococci infection.
- To characterize bacterial forms and host responses following streptococcal challenge.
Main Methods:
- Administration of streptococcal cell wall mucopeptide (intraperitoneally and intravenously) to mice and rabbits.
- Subsequent challenge with virulent Group A streptococci.
- Autopsy and serological analysis of recovered Group A streptococci.
- Investigation of filterable bacterial forms using L form media.
Main Results:
- Mucopeptide injection enhanced resistance to virulent Group A streptococci in mice.
- Rabbits exhibited fever responses resembling endotoxin after mucopeptide administration.
- Late-stage recovery of identical Group A streptococci was diminished by prior cell wall administration.
- Group A-variant streptococci and filterable bacterial forms (L forms) were recovered from surviving mice.
Conclusions:
- Streptococcal cell wall mucopeptide possesses immunomodulatory properties that enhance resistance to infection.
- The study identified novel bacterial forms associated with persistent streptococcal infections.
- Further research into these bacterial forms may reveal new insights into streptococcal pathogenesis and treatment strategies.