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Natural antibodies in man to Streptococcus mutans: specificity and quantification
Immunology
|May 1, 1984
Summary
Natural antibodies in humans bind to Streptococcus mutans, a key bacterium in dental caries. These antibodies, including IgG, IgA, and IgM, target various cell wall antigens like SA I/II and glucosyltransferase.
Area of Science:
- Immunology
- Microbiology
- Oral Health
Background:
- Streptococcus mutans is a primary etiological agent of dental caries.
- Understanding the human immune response to S. mutans is crucial for developing effective prevention strategies.
Purpose of the Study:
- To quantify serum antibodies against whole cells of Streptococcus mutans in humans.
- To identify the specific cell wall antigens of S. mutans that elicit antibody responses.
Main Methods:
- Solid-phase radioimmunoassay was used to measure isotype-specific antibodies (IgG, IgA, IgM) against whole S. mutans cells in 108 subjects.
- Inhibition experiments with purified cell wall antigens (SA I/II, glucosyltransferase, c polysaccharide, lipoteichoic acid) were performed.
Main Results:
- All subjects possessed serum antibodies to S. mutans, with mean concentrations of IgG (84 µg/ml), IgA (26 µg/ml), and IgM (9 µg/ml).
- Antibody binding to whole cells was significantly inhibited by protein antigens SA I/II (30%) and glucosyltransferase (GTF) (30%), indicating they are major immunogenic components.
- Antibodies were also induced by c polysaccharide (25% inhibition) and lipoteichoic acid (16% inhibition), suggesting a broad immune response to various S. mutans antigens, some shared with other bacteria.
Conclusions:
- Natural human antibodies effectively bind to Streptococcus mutans whole cells.
- Protein antigens SA I/II and GTF are major targets of the humoral immune response against S. mutans.
- The immune response to S. mutans involves multiple antigens, including both species-specific and cross-reactive components, highlighting the complexity of host defense against this oral pathogen.