Differential expression of Toll-like receptor-2, -4 and -9 in follicle-associated epithelium from epithelia of both follicle-associated intestinal villi and ordinary intestinal villi in rat Peyer's patches.
The expressions of Toll-like receptor (TLR) -2, -4 and -9 were immunohistochemically investigated in the follicle-associated epithelium (FAE), and epithelia of the follicle-associated intestinal villus (FAIV) and ordinary intestinal villus (IV) in rat Peyer's patch regions with no bacterial colonies on the mucous membranes. TLR-2 was expressed in the striated borders of microvillous columnar epithelial cells (MV) in both FAIV and IV except in the apices. However, TLR-2 expression in the striated borders was weaker in the epithelium of the follicular side of FAIV (f-FAIV) than in epithelia of IV and the anti-follicular side of FAIV. TLR-4 and -9 were not expressed in the FAIV and IV. In the FAE, TLR-2, -4 and -9 were not expressed in the striated borders of MV, but the roofs of some typical M-cells were immunopositive for all TLRs. Especially, no TLR-positive MV were found at the FAE sites where M-cells appeared most frequently. In the follicle-associated intestinal crypt (FAIC), immunopositivity for all TLRs was observed in the striated borders of MV and the luminal substances. In conclusion, the lower levels of TLR-2 in both FAE and the epithelium of f-FAIV probably reduce recognition of indigenous bacteria. TLR-2, -4 and -9 appear not to participate directly in differentiation of MV into M-cells, because TLRs were not expressed in any MV in the upstream region of M-cells in FAE with no settlement of indigenous bacteria in the rat Peyer's patches.
Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan.
Hideto
H
Yuasa
Youhei
Y
Mantani
Natsumi
N
Masuda
Miho
M
Nishida
Junichi
J
Kawano
Toshifumi
T
Yokoyama
Nobuhiko
N
Hoshi
Hiroshi
H
Kitagawa
D000818:Animals; D002454:Cell Differentiation; D004847:Epithelial Cells / Q000378:metabolism*; D007082:Ileum / Q000166:cytology / Q000378:metabolism; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism; D008297:Male; D010581:Peyer's Patches / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013047:Specific Pathogen-Free Organisms; D051193:Toll-Like Receptors / Q000378:metabolism*
D051193:Toll-Like Receptors