title: Human leukocyte antigen F protein is expressed in the extra-villous trophoblasts but not on the cell surface of them.
abstract: OBJECTIVE
  Human leukocyte antigen (HLA)-F together with other class 1b HLAs may play a pivotal role in immunological interaction at feto-maternal interface. However, it is not elucidated whether HLA-F is expressed on cell surface of extra-villous trophoblasts (EVTs).
  
  
  METHODS
  The localization of HLA-F in placenta of each trimester was investigated by immunohistochemistry. The expression modality of HLA-F molecule was compared with that of HLA-G in cultured EVTs using flowcytometry.
  
  
  CONCLUSIONS
  In immunohistochemical study, remarkable staining for HLA-F was confirmed in EVTs throughout gestation. HLA-F expression was restricted to be intracellular in cultured EVTs. HLA-F expression was increased with time in culture, which was accompanied by the increase of cell surface HLA-G. Consequently, HLA-F lacking in cell surface expression on EVTs may not contribute to the direct cell-to-cell immune reaction but might work supportively modifying the function of HLA-G.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nagamatsu
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Fujii
authors.forename: Junko
authors.initials: J
authors.lastname: Matsumoto
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yamashita
authors.forename: Shiro
authors.initials: S
authors.lastname: Kozuma
authors.forename: Yuji
authors.initials: Y
authors.lastname: Taketani
mesh_terms: D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006680:HLA Antigens / Q000032:analysis* / Q000378:metabolism; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D011247:Pregnancy; D014327:Trophoblasts / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
chemical_list: D006680:HLA Antigens; C062341:HLA-F antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I