Psg18 is specifically expressed in follicle-associated epithelium.
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.
Kawano
Kazuya
K
Laboratory for Epithelial Immunobiology, Research Center for Allergy and Immunology, RIKEN, Kanagawa, Japan.
Ebisawa
Masashi
M
Hase
Koji
K
Fukuda
Shinji
S
Hijikata
Atsushi
A
Kawano
Sayaka
S
Date
Yasuhiro
Y
Tsuneda
Satoshi
S
Itoh
Kikuji
K
Ohno
Hiroshi
H
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
D011257:Pregnancy Proteins; D012333:RNA, Messenger; C412965:pregnancy specific glycoprotein 18