Lipopolysaccharide-binding protein: localization in secretory granules of Paneth cells in the mouse small intestine.
Lipopolysaccharide (LPS)-binding protein (LBP) is an acute-phase protein involved in the host's response to endotoxin and mainly synthesized and secreted to the blood by the liver. But in addition, LBP is also made by extrahepatic cells, including the enterocyte-like cell line Caco-2. To study in closer detail the synthesis and storage of LBP in the intestinal mucosal epithelium, we performed an immunolocalization of LBP in mouse small intestine. By immunofluorescence microscopy, an antibody recognizing the 58-60 kDa protein of LBP distinctly labeled a small population of cells located deep into the crypts. This cell population was also positive for lysozyme and alpha-defensin 4, identifying Paneth cells as the main intestinal LBP-producing cells. By immunogold electron microscopy, intense labeling was observed in the secretory granules of these cells. We conclude that Paneth cells express LBP together with other proteins acting in the innate immune response of the gut, such as lysozyme, defensins and intelectin.
Hansen
Gert H
GH
Department of Cellular and Molecular Medicine, The Panum Institute, The University of Copenhagen, Building 6.4, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
Rasmussen
Karina
K
Niels-Christiansen
Lise-Lotte
LL
Danielsen
E Michael
EM
D000209:Acute-Phase Proteins / Q000378:metabolism*; D000818:Animals; D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D006801:Humans; D007421:Intestine, Small / Q000378:metabolism* / Q000648:ultrastructure; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D016253:Microscopy, Immunoelectron; D009113:Muramidase / Q000378:metabolism; D019879:Paneth Cells / Q000378:metabolism* / Q000648:ultrastructure; D022142:Secretory Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D023084:alpha-Defensins / Q000378:metabolism; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D009113:Muramidase; D023084:alpha-Defensins; D000099231:Lipopolysaccharide-Binding Protein