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Published on: May 2, 2018
Interleukin-6 is essential for zwitterionic polysaccharide-mediated abscess formation
Sonja Meemboor1, Janina Mertens, Eva Flenner
1Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne Medical Centre, Cologne, Germany.
Innate Immunity
|November 10, 2009
Summary
Interleukin-6 (IL-6) is crucial for linking innate and adaptive immunity in bacterial abscess formation. This study shows IL-6 drives CD4+ T-cell responses essential for abscess capsule development.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Abscess formation, often linked to secondary peritonitis, presents significant morbidity and mortality.
- CD4+ T-cells are essential for abscess development.
- Zwitterionic polysaccharides (ZPSs) are bacterial antigens that modulate the immune system by stimulating CD4+ T-cells via MHC class II.
- The Streptococcus pneumoniae serotype 1 capsular polysaccharide Sp1 is a ZPS that promotes T-cell-dependent abscess formation in mice.
Purpose of the Study:
- To investigate the role of Interleukin-6 (IL-6) in intraperitoneal abscess formation mediated by the zwitterionic polysaccharide Sp1.
- To elucidate the mechanisms by which Sp1 and IL-6 interact to promote abscess development.
Main Methods:
- Utilized an experimental mouse model of intraperitoneal abscess formation induced by Sp1.
- Investigated the secretion of IL-6 by antigen-presenting cells (macrophages and dendritic cells) within the abscess microenvironment.
- Assessed the impact of IL-6 deficiency (using IL-6-deficient mice) and IL-6 neutralization (using a specific antibody) on abscess formation.
- Analyzed the effects of Sp1 on CD4+ T-cell apoptosis and IL-17 expression in an IL-6-dependent manner.
Main Results:
- Macrophages and dendritic cells, key antigen-presenting cells, secrete IL-6 and are incorporated into the abscess capsule.
- Sp1 inhibits CD4+ T-cell apoptosis and induces IL-17 expression by CD4+ T-cells, dependent on IL-6.
- Abrogation of IL-6 signaling in IL-6-deficient mice or through antibody neutralization significantly inhibited Sp1-induced abscess formation.
- Demonstrated that IL-6 links innate and adaptive immunity in this polysaccharide-mediated abscess formation model.
Conclusions:
- Interleukin-6 plays an essential and multifaceted role in the development of intraperitoneal abscesses induced by zwitterionic polysaccharides.
- IL-6 is critical for linking innate immune responses (antigen presentation) with adaptive immune responses (T-cell activation and survival) during abscess formation.
- Targeting the IL-6 pathway may represent a therapeutic strategy for managing bacterial abscesses.
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