title: HLA-F is a surface marker on activated lymphocytes.
abstract: Of the three nonclassical class I antigens expressed in humans, HLA-F has been least characterized with regard to expression or function. In this study, we examined HLA-F expression focusing on lymphoid cells, where our previous work with homologous cell lines had demonstrated surface HLA-F expression. HLA-F protein expression was observed by Western blot analysis in all resting lymphocytes, including B cells, T cells, NK cells, and monocytes, all of which lacked surface expression in the resting state. Upon activation, using a variety of methods to activate different lymphocyte subpopulations, all cell types that expressed HLA-F intracellularly showed an induction of surface HLA-F protein. An examination of peripheral blood from individuals genetically deficient for TAP and tapasin expression demonstrated the same activation expression profiles for HLA-F,but with altered kinetics post-activation. Further analysis of CD41+CD25+1 Treg showed that HLA-F was not upregulated on the major fraction of these cells when they were activated,whereas CD41+CD25- T cells showed strong expression of surface HLA-F when activated under identical conditions. These findings are discussed with regard to possible functions for HLA-F and its potential clinical use as a marker of an activated immune response.
authors.affiliation: The Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle,WA 98109-1024,USA.
authors.forename: Ni
authors.initials: N
authors.lastname: Lee
authors.forename: Akiko
authors.initials: A
authors.lastname: Ishitani
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Geraghty
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D015704:CD4 Antigens / Q000096:biosynthesis; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007156:Immunologic Memory; D053645:Interleukin-2 Receptor alpha Subunit / Q000096:biosynthesis; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D026901:Membrane Transport Proteins / Q000172:deficiency / Q000235:genetics; D021381:Protein Transport / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
chemical_list: D018528:ATP-Binding Cassette Transporters; D015704:CD4 Antigens; C062341:HLA-F antigens; D015395:Histocompatibility Antigens Class I; D053645:Interleukin-2 Receptor alpha Subunit; D026901:Membrane Transport Proteins; C107762:tapasin; C477327:transporter associated with antigen processing (TAP)