Antimicrobial peptides are present in immune and host defense cells of the human respiratory and gastrointestinal tracts

Department of Anatomy, Chair II, Ludwig Maximilian University, 80336 München, Germany.
Cell and Tissue Research (Impact Factor: 3.57). 07/2006; 324(3):449-56. DOI: 10.1007/s00441-005-0127-7
Source: PubMed


Previous studies have implicated antimicrobial peptides in the host defense of the mammalian intestinal and respiratory tract. The aim of the present study has been to characterize further the expression of these molecules in non-epithelial cells of the human pulmonary and digestive systems by detailed immunohistochemical analysis of the small and large bowel and of the large airways and lung parenchyma. Additionally, cells obtained from bronchoalveolar lavage were analyzed by fluorescent activated cell sorting and immunostaining of cytospin preparations. hBD-1, hBD-2, and LL-37 were detected in lymphocytes and macrophages in the large airways, lung parenchyma, duodenum, and colon. Lymphocytes positive for the peptides revealed a staining pattern and distribution that largely matched that of CD3-positive and CD8-positive T-cells. Macrophages with positive staining for the antimicrobial peptides also stained positively for CD68 and CD74. In view of the morphology of the LL-37-positive and hBD-2-positive mucosal lymphocytes, they are probably also B-cells. Thus, antimicrobial peptides of the defensin and cathelicidin families are present in a variety of non-epithelial cells of mucosal organs. These findings confirm that antimicrobial peptides have multiple functions in the biology of the mucosa of these organs.

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Available from: Pia Unterberger, Sep 06, 2015
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    • "In addition to the direct antimicrobial function, they may act as ion channels and stimulators of angiogenesis . Other reports suggest a role in wound repair and in cell proliferation, (Heilborn et al., 2003) or that they function as mediators of inflammation and chemotaxis (Wah et al., 2006). "
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    • "HBD-2 has been found in hyperplastic-stratified squamous epithelia in odontogenic keratocysts and radicular cysts (Yoshimoto et al, 2004). HBD-2 was also found in the cytoplasm of epithelial cells located through the upper spinous layer to the parakeratinized layer of the buccal epithelia from subjects with oral candidiasis (Sawaki et al, 2002), in T-lymphocytes cd3, cd8, and macrophages (Wah et al, 2006). The expression of HBD-2 was upregulated by TNF-a in patients with lichen planus (Abiko et al, 2002) and by IL-1b in keratinocytes (Liu et al, 2002). "
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    • "Although in vitro stimulation with lipopolysaccharide did not have any effect on the S100A7 expression, a significant downregulation of S100A7 was detected in infected tonsils. This is in contrast to other studies concerning AMPs and tonsillar infection, where, in general, an increase of these proteins is described during infection (Song et al., 2006; Wah et al., 2006). Although S100A7 expression is induced in the skin in response to stimulation with bacterial products (Glaser et al., 2005), this does not seem to be the case in palatine tonsils, indicating that S100A7 may have tissuespecific functions. "
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