title: Psg18 is specifically expressed in follicle-associated epithelium.
abstract: Pregnancy-specific glycoproteins (Psgs) secreted by the placenta regulate the immune system to ensure the survival of the fetal allograft by inducing IL-10, an anti-inflammatory cytokine. However, it is unknown whether Psgs are involved in more general aspects of immune response other than maternal immunity. Here, we report that Psg18 is highly expressed in the follicle-associated epithelium (FAE) overlaying Peyer's patches (PPs). Bioinformatics analysis with Reference Database for Immune Cells (RefDIC) as well as RT-PCR data demonstrated that Psg18 is exclusively expressed in FAE in adult mice, in contrast to other Psg family members that are either not expressed or only slightly expressed in FAE. Psg18 expression was observed in FAE of germ-free-conditioned mice, and was slightly upregulated after bacterial inoculation. In situ hybridization analysis revealed that Psg18 is widely expressed throughout FAE. Furthermore, Psg18 protein is deposited on the extracellular matrix in the subepithelial dome beneath FAE, where antigen-presenting cells accumulate. These results suggest that Psg18 is an FAE-specific marker protein that could promote interplay between FAE and immune cells in mucosa-associated lymphoid tissues.
authors.affiliation: Laboratory for Epithelial Immunobiology, Research Center for Allergy and Immunology, RIKEN, Kanagawa, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kawano
authors.forename: Masashi
authors.initials: M
authors.lastname: Ebisawa
authors.forename: Koji
authors.initials: K
authors.lastname: Hase
authors.forename: Shinji
authors.initials: S
authors.lastname: Fukuda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hijikata
authors.forename: Sayaka
authors.initials: S
authors.lastname: Kawano
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Date
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsuneda
authors.forename: Kikuji
authors.initials: K
authors.lastname: Itoh
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohno
mesh_terms: D000818:Animals; D019295:Computational Biology; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism*; D005109:Extracellular Matrix / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D009928:Organ Specificity; D006080:Ovarian Follicle / Q000166:cytology / Q000378:metabolism*; D010581:Peyer's Patches / Q000166:cytology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D021381:Protein Transport; D034443:RNA Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D011257:Pregnancy Proteins; D012333:RNA, Messenger; C412965:pregnancy specific glycoprotein 18