title: The surface expression of HLA-F on decidual trophoblasts increases from mid to term gestation.
abstract: HLA-F has recently only begun to be studied in earnest, and has been thought not to be expressed on the cell surface. However, in our previous report, we demonstrated surface expression of HLA-F on extravillous trophoblasts (EVTs) invading the decidua in term placental tissues. To better understand its function, we attempted to determine when surface expression of HLA-F begins during normal pregnancy, and whether there is a difference in expression between normal and preeclamptic placentas, by comparing the expression of HLA-G and -E by immunohistochemical staining with anti-HLA-E, -F and -G antibodies (3D12, 3D11 and 87G, respectively). In EVTs, HLA-F was expressed only in the cytoplasm weakly during the first trimester, after which expression increased and moved to the cell surface with the progression of pregnancy from the second trimester, which was confirmed by the results of double-labeled immunofluorescence staining with anti-HLA-F and anti-HLA-G antibodies, and by flow cytometry using trophoblasts isolated from the decidua. HLA-E showed similar expression as HLA-F, though it was expressed on the cell surface from the first trimester, while HLA-G was expressed strongly in the cytoplasm and on the cell surface during all stages of pregnancy. The expressions of HLA-E, -F and -G in preeclamptic placentas were not different from those in normal placentas, though there were a greater number of necrotic EVTs in preeclampsia. The increase in expression of HLA-E and HLA-F from the second trimester to full term was coincident with the timing of rapid growth of the fetus. Our results suggest that these may function together to prepare an environment that supports fetal growth.
authors.affiliation: Department of Legal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara-shi Nara 634-8521, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Shobu
authors.forename: Noriko
authors.initials: N
authors.lastname: Sageshima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tokui
authors.forename: Motoko
authors.initials: M
authors.lastname: Omura
authors.forename: Keigo
authors.initials: K
authors.lastname: Saito
authors.forename: Yuka
authors.initials: Y
authors.lastname: Nagatsuka
authors.forename: Mari
authors.initials: M
authors.lastname: Nakanishi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Hatake
authors.forename: Akiko
authors.initials: A
authors.lastname: Ishitani
mesh_terms: D000328:Adult; D002462:Cell Membrane / Q000276:immunology; D003656:Decidua / Q000166:cytology / Q000276:immunology*; D005260:Female; D006680:HLA Antigens / Q000032:analysis*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D011225:Pre-Eclampsia / Q000276:immunology; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000276:immunology*; D011263:Pregnancy Trimester, Third / Q000276:immunology*; D014327:Trophoblasts / Q000276:immunology*; D000097625:HLA-E Antigens
chemical_list: D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; D000097625:HLA-E Antigens; C062341:HLA-F antigens