Intestinal barriers to bacteria and their toxins.
Immunologic and nonimmunologic processes work together to protect the host from the multitude of microorganisms residing within the intestinal lumen. Mechanical integrity of the intestinal epithelium, mucus in combination with secretory antibody, antimicrobial metabolites of indigenous microorganisms, and peristalsis each limit proliferation and systemic dissemination of enteric pathogens. Uptake of microorganisms by Peyer's patches and other intestinal lymphoid structures and translocation circumvent the mucosal barrier, especially in immunosuppressed individuals. Improved understanding of the composition and limitation of the intestinal barrier, coupled with advances in genetic engineering of immunogenic bacteria, development of oral delivery systems, and immunomodulators, now make enhancement of mucosal barriers feasible.
Infectious Diseases Department, Naval Medical Research Institute, Bethesda, Maryland 20814-5055.
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Walker
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Owen
D000818:Animals; D001424:Bacterial Infections / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology*; D005744:Gastric Acid / Q000502:physiology; D007413:Intestinal Mucosa / Q000276:immunology* / Q000382:microbiology / Q000528:radiation effects; D008070:Lipopolysaccharides / Q000502:physiology
D001427:Bacterial Toxins; D008070:Lipopolysaccharides