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Immunochemical and chemical studies on streptococcal group-specific carbohydrates
Journal of Immunology (Baltimore, Md. : 1950)
|June 1, 1975
Summary
Structural analysis of streptococcal carbohydrates reveals distinct compositions. Group A and A-variant (AV) streptococci share a rhamnose backbone, differing in terminal residues, impacting immunochemical properties.
Area of Science:
- Microbiology
- Carbohydrate Chemistry
- Immunology
Background:
- Streptococcal carbohydrates are crucial for serological classification and virulence.
- Understanding the structural basis of group-specific antigens is essential for vaccine development and diagnostics.
Purpose of the Study:
- To elucidate the detailed structures of carbohydrates from Group A, C, and A-variant (AV) streptococci.
- To compare the structural features and immunochemical properties of these related streptococcal groups.
Main Methods:
- Periodate oxidation to cleave specific glycosidic linkages.
- Permethylation analysis to determine the linkage positions of sugar residues.
- Immunochemical comparison of intact and modified polysaccharides using antisera.
Main Results:
- Group A and AV carbohydrates share a common 1,2- and 1,3-linked rhamnose backbone.
- Group A carbohydrate has terminal N-acetylglucosamine, while AV is a rhamnose homopolymer.
- Group C carbohydrate contains N-acetylgalactosamine residues, complicating direct comparison, with approximately 50% terminal and 50% internal linkage.
Conclusions:
- The structural differences, particularly terminal residues, explain the distinct immunochemical profiles of Group A, C, and AV streptococci.
- Periodate oxidation highlights the role of terminal hexosamines in cross-reactivity, suggesting specific antigenic determinants.