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Streptococcal cross-reacting antigen and the bundle of His
Abstract:
Five sera raised in rabbits against three strains of Streptococcus pyogenes (grown in semi-synthetic media) were shown by immunofluorescence to have antibodies reacting with both myocardial and conducting fibres. The pattern of staining on the conducting fibres was different to that on myocardial fibres and suggested the presence of larger amounts of cross-reacting antigen. Most work was done on ox heart, but the results were confirmed on human heart and rabbit heart. Absorption studies, carried out with three sera on ox heart only, showed that absorption with the homologous organism abolished in parallel the staining of both types of fibre. Absorption with heterologous organisms was less effective indicating the existence of more than one cardiac cross-reacting antigen. Absorption with myocardium, suggested that the conducting fibres contained streptococcal cross-reacting antigens additional to those found in the contractile fibres.
Insights
Rabbit sera against Streptococcus pyogenes contain antibodies that react with heart fibers. These antibodies target distinct antigens in myocardial and conducting fibers, suggesting a link between streptococcal infection and cardiac autoimmunity.
Area of Science:
- Immunology
- Cardiology
- Microbiology
Background:
- Streptococcus pyogenes is a pathogen known to cause various infections.
- Cardiac involvement following streptococcal infections, such as rheumatic heart disease, is a significant clinical concern.
- The presence of cross-reactive antigens between streptococci and cardiac tissues is hypothesized.
Purpose of the Study:
- To investigate the presence and nature of antibodies in rabbit sera raised against Streptococcus pyogenes that cross-react with cardiac tissues.
- To differentiate the antigenic targets within myocardial and conducting fibers.
Main Methods:
- Immunofluorescence assays were used to detect antibody binding to myocardial and conducting fibers.
- Sera were raised in rabbits against three strains of Streptococcus pyogenes.
- Absorption studies with homologous and heterologous organisms, as well as cardiac tissues, were performed.
Main Results:
- Rabbit sera against Streptococcus pyogenes showed positive immunofluorescence staining on both myocardial and conducting fibers of ox, human, and rabbit hearts.
- Distinct staining patterns were observed on myocardial versus conducting fibers, suggesting different antigen distributions.
- Absorption studies indicated that homologous organism absorption removed reactivity to both fiber types, while heterologous organisms were less effective.
- Conducting fibers appeared to possess additional streptococcal cross-reactive antigens not present in contractile fibers.
Conclusions:
- Antibodies generated against Streptococcus pyogenes can cross-react with cardiac tissues.
- There are shared and distinct antigens between Streptococcus pyogenes and cardiac fibers, particularly in conducting tissues.
- These findings support the hypothesis of an autoimmune mechanism in cardiac complications following streptococcal infections.