title: Toll-like receptor 2 is expressed on the intestinal M cells in swine.
abstract: The Toll-like receptor (TLR) 2 binds a wide variety of microbial cell wall components. In this study, we investigated the expression pattern of TLR2 in adult swine gut-associated lymphoid tissues using real-time quantitative PCR, Western blotting, immunohistochemistry, and flow cytometric analysis. The mRNA for TLR2 was preferentially expressed in the mesenteric lymph nodes (MLNs) and Peyer's patches (Pps) of adult swine. Expression in these two tissues was approximately 15- and 9-fold higher than that of spleen, respectively. Western blotting further confirmed that the TLR2 protein was highly expressed in the MLNs and Pps. Interestingly, TLR2-expressing cells were found not only in immune cells, such as T cells and B cells, but also in membranous (M) cells. In addition, double immunostaining for TLR2 and cytokeratin 18 revealed that TLR2 was strongly expressed not only in the cytoplasm but also in the apical membrane of the pocket-like M cells. These results indicate that TLR2 on the MLNs and Pps enable the host defense to respond to a variety of cell wall components. Furthermore, the potential function of TLR2 as a pattern recognition receptor and its cellular distribution suggest that TLR2 plays an important role in ligand-specific transcytosis and transport in M cells.
authors.affiliation: Laboratory of Animal Products Chemistry, Graduate School of Agricultural Science, Tohoku University, Aobaku, Sendai 981-8555, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Tohno
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimosato
authors.forename: Haruki
authors.initials: H
authors.lastname: Kitazawa
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Katoh
authors.forename: Iliyan Dimitrov
authors.initials: ID
authors.lastname: Iliev
authors.forename: Toshiro
authors.initials: T
authors.lastname: Kimura
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawai
authors.forename: Kouichi
authors.initials: K
authors.lastname: Watanabe
authors.forename: Hisashi
authors.initials: H
authors.lastname: Aso
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Tadao
authors.initials: T
authors.lastname: Saito
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D007633:Keratins / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D013552:Swine; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors
chemical_list: D017931:DNA Primers; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors; D007633:Keratins