Bile regulates the expression of major histocompatibility complex class II molecules on rat intestinal epithelium.
OBJECTIVE
Major histocompatibility complex (MHC) class II molecules are expressed on intestinal epithelial cells, and the intensity of this expression is regulated. The aim of this study was to test the hypothesis that bile regulates the expression of MHC class II molecules on intestinal epithelium.


METHODS
Rats were deprived of intestinal bile by external drainage for 24 or 48 hours, and their intestines were collected, sectioned, and stained with the anti-MHC class II monoclonal antibodies OX4 and OX6. For one group of rats, bile flow was deviated from its usual entry point to the ileum.


RESULTS
Compared with intact animals, MHC class II expression was observed to be diminished within 24 hours and totally absent after 48 hours of bile drainage. For the group in which bile flow was deviated to the ileum, staining was only observed in the region distal to the entry point. Analysis by bioassay and enzyme-linked immunosorbent assay of bile showed the presence of tumor necrosis factor and interferon gamma, respectively.


CONCLUSIONS
It is concluded that the presence of bile is required for the expression of MHC class II molecules on gut epithelium and that the cytokine components of bile may be the inducing agents.
Hamilton
L J
LJ
School of Microbiology and Immunology, University of New South Wales, Sydney, Australia.
Dai
Y
Y
Jackson
G D
GD
D000818:Animals; D000911:Antibodies, Monoclonal; D001646:Bile / Q000737:chemistry / Q000502:physiology*; D001681:Biological Assay; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D007371:Interferon-gamma / Q000032:analysis; D007413:Intestinal Mucosa / Q000276:immunology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar; D013194:Staining and Labeling; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma