Presentation Information
[P04-601]Bioinformatic Prediction of Autoimmune Responses: How Streptococcal Glucosyltransferase Triggers Anti-double-stranded DNA Antibody Production
○Hsu CHIH CHIEH1, Hong Shin Min1, Chu Kai Yang1 (1. Department of Microbiology, Soochow University, Taipei, Taiwan (Taiwan))
Keywords:
Streptococcal Glucosyltransferase,Bioinformatic Prediction,Anti-double-stranded DNA Antibody Production,infective endocarditis
[Purpose]This study aims to investigate how bacteremia caused by oral commensal Streptococcus species modulates immunological tolerance to self-antigens, contributing to the development of autoimmune diseases. Specifically, it explores the mechanism by which Streptococcus mutans (S. mutans) induces anti-double-stranded (ds) DNA antibodies.
[Method]The research utilized a combination of clinical studies, animal models, and molecular analysis: Clinical Analysis: Screening sera from patients with streptococcal bacteremia for autoantibodies (anti-dsDNA and anti-phospholipid antibodies). Murine Model: Intravenous infection of mice with S. mutans to observe the induction of anti-dsDNA antibodies. Functional & Structural Analysis: Identification of key surface proteins via functional assays. Structural modeling to identify DNA-binding motifs and surface charge distribution. ELISA-based ligand assays to confirm interaction between proteins and DNA.
[Results]Clinical Findings: Approximately 60% of patients with streptococcal bacteremia exhibited autoantibodies; roughly 30% had anti-dsDNA antibodies and 30% had anti-phospholipid antibodies. Key Factor Identification: The surface protein glucosyltransferase B (GtfB) of S. mutans was identified as the primary factor responsible for inducing anti-dsDNA antibodies. Correlation: A positive correlation was found between the titers of anti-GtfB antibodies and anti-dsDNA antibodies in patient sera. Molecular Evidence: GtfB possesses a large positively charged surface area and confirmed DNA-binding activity. The C-terminal repeat domain of GtfB structurally resembles a dsDNA helix.
[Consideration]The researchers hypothesized two primary mechanisms by which GtfB triggers the production of anti-dsDNA antibodies: Direct Binding: GtfB binds directly to bacterial DNA, potentially forming a complex that enhances immune recognition. Structural Mimicry: The physical structure of GtfB's C-terminal domain mimics a dsDNA helix, leading the immune system to produce cross-reactive antibodies that also target the host's own DNA.
[Conclusion]GtfB contributes to anti-dsDNA antibody production through both DNA binding and structural mimicry. These findings suggest that S. mutans bacteremia plays a significant role in the pathogenesis of certain autoimmune diseases. Further research is required to fully understand the clinical implications of this relationship in human patients.
[Method]The research utilized a combination of clinical studies, animal models, and molecular analysis: Clinical Analysis: Screening sera from patients with streptococcal bacteremia for autoantibodies (anti-dsDNA and anti-phospholipid antibodies). Murine Model: Intravenous infection of mice with S. mutans to observe the induction of anti-dsDNA antibodies. Functional & Structural Analysis: Identification of key surface proteins via functional assays. Structural modeling to identify DNA-binding motifs and surface charge distribution. ELISA-based ligand assays to confirm interaction between proteins and DNA.
[Results]Clinical Findings: Approximately 60% of patients with streptococcal bacteremia exhibited autoantibodies; roughly 30% had anti-dsDNA antibodies and 30% had anti-phospholipid antibodies. Key Factor Identification: The surface protein glucosyltransferase B (GtfB) of S. mutans was identified as the primary factor responsible for inducing anti-dsDNA antibodies. Correlation: A positive correlation was found between the titers of anti-GtfB antibodies and anti-dsDNA antibodies in patient sera. Molecular Evidence: GtfB possesses a large positively charged surface area and confirmed DNA-binding activity. The C-terminal repeat domain of GtfB structurally resembles a dsDNA helix.
[Consideration]The researchers hypothesized two primary mechanisms by which GtfB triggers the production of anti-dsDNA antibodies: Direct Binding: GtfB binds directly to bacterial DNA, potentially forming a complex that enhances immune recognition. Structural Mimicry: The physical structure of GtfB's C-terminal domain mimics a dsDNA helix, leading the immune system to produce cross-reactive antibodies that also target the host's own DNA.
[Conclusion]GtfB contributes to anti-dsDNA antibody production through both DNA binding and structural mimicry. These findings suggest that S. mutans bacteremia plays a significant role in the pathogenesis of certain autoimmune diseases. Further research is required to fully understand the clinical implications of this relationship in human patients.
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