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The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis
Published on: February 19, 2013
Germ-free and colonized mice generate the same products from enteric prodefensins
K Putsep1, L G Axelsson, A Boman
1Microbiology and Tumor Biology Center, Medical Biochemistry and Biophysics, Chemistry I, and Cell and Molecular Biology, Laboratory for Medical Microbial Ecology, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
The Journal of Biological Chemistry
|September 30, 2000
Summary
Germ-free mice reveal that defensins are key antibacterial factors in the gut, comprising 15% of activity. Their processing occurs similarly, regardless of bacterial presence, indicating innate immune system function.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Germ-free mice allow studying innate antibacterial components without microbial interference.
- Understanding gut antimicrobial factors is crucial for host defense and microbiome research.
Purpose of the Study:
- To identify and characterize antibacterial factors in the small intestine of mice.
- To investigate the role and processing of defensins in both germ-free and colonized mice.
Main Methods:
- Extraction and high-pressure liquid chromatography (HPLC) fractionation of small intestinal contents.
- Mass spectrometry and sequence analysis to identify antimicrobial compounds.
- Comparative analysis of defensin processing in germ-free versus colonized mice.
Main Results:
- Defensins accounted for approximately 15% of total antibacterial activity in both germ-free and colonized mice.
- The same mature enteric defensins (1, 2, 3, 4, and 6) were identified in both groups.
- Prodefensin processing occurred via cleavage at a Ser/Ala-Leu bond, yielding specific propiece peptides, independent of bacterial colonization.
Conclusions:
- Enteric defensins are significant innate antibacterial components in the mouse gut.
- Defensin processing pathways are conserved and function independently of the gut microbiome.
- This suggests a fundamental role for defensins in host defense against potential pathogens.
