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Degradation of intestinal glycoproteins by pathogenic Shigella flexneri

R Prizont

    Infection and Immunity
    |May 1, 1982
    PubMed

    Insights

    Shigella flexneri 4b utilizes a unique enzyme to degrade blood group B sugars in intestinal mucins, fueling its growth. This bacterial alpha-galactosidase activity enhances pathogen proliferation in the gut environment.

    Area of Science:

    • Microbiology
    • Glycobiology
    • Gastroenterology

    Background:

    • Intestinal mucins are crucial for gut barrier function.
    • Pathogenic bacteria often interact with host glycans for colonization.

    Purpose of the Study:

    • To investigate the role of intestinal mucins in supporting the growth of pathogenic Shigella flexneri 4b.
    • To identify mechanisms by which Shigella flexneri 4b colonizes the ileocolonic environment.

    Main Methods:

    • In vitro culture of germfree cecal mucin glycoproteins with Shigella flexneri 4b.
    • Enzymatic degradation assays using bacterial glycosidases.
    • In vivo experiments with monocontaminated mice to analyze fecal enzyme activity.
    • Assessment of blood group B reactivity in cecal mucins.

    Main Results:

    • Shigella flexneri 4b demonstrated a 940-fold increase in concentration when grown on cecal mucin glycoproteins.
    • A blood group B-degrading glycosidase (alpha-galactosidase) was identified in vitro and in vivo.
    • Fecal alpha-galactosidase activity peaked 5 days post-contamination in mice.
    • Bacterial enzyme activity degraded the blood group B reactivity of cecal mucins.

    Conclusions:

    • Shigella flexneri 4b possesses enzymatic machinery to degrade host mucin glycans.
    • Degradation of mucin glycoproteins, specifically blood group B antigens, likely facilitates pathogen proliferation in the gut.
    • This enzymatic adaptation is a key factor in the ileocolonic colonization by Shigella flexneri 4b.

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