title: Distribution and kinetics of SR-PSOX/CXCL16 and CXCR6 expression on human dendritic cell subsets and CD4+ T cells.
abstract: Dendritic cells (DCs) coordinate T cell responses by producing T cell-attracting chemokines and by inducing the expression of chemokine receptors on T cells. Scavenger receptor for phosphatidylserine and oxidized lipoprotein (SR-PSOX)/CXC chemokine ligand 16 (CXCL16) is a unique chemokine that also functions as an endocytic receptor and an adhesion molecule in its membrane-bound form. SR-PSOX/CXCL16 is the only known ligand of CXC chemokine receptor 6 (CXCR6) that is expressed on activated T cells and thus, may play an important role in enhancing effector functions of T cells. Here, we investigated the expression of SR-PSOX/CXCL16 on human DC subsets and that of CXCR6 on T cell subpopulations to elucidate the dynamics of CXCL16/CXCR6 interaction in DC/T cell responses. Membrane-bound SR-PSOX/CXCL16 was expressed on macrophages, monocyte-derived DCs, and blood myeloid DCs, and the expression increased after DC maturation. Myeloid antigen-presenting cells constitutively secreted SR-PSOX/CXCL16 for an extended period, suggesting the involvement of CXCL16 in peripheral and lymphoid tissues. Plasmacytoid DCs hardly expressed SR-PSOX/CXCL16 on their surfaces but secreted significant amounts of SR-PSOX/CXCL16. A subset of CD4+ effector memory T (T(EM)) cells constitutively expressed CXCR6, whereas central memory T cells (T(CM)) and naive T cells did not. Upon stimulation with mature DCs, however, the expression of CXCR6 on T(CM) cells was markedly up-regulated, whereas the expression on naive T cells was induced only weakly. These results suggest that the interaction between SR-PSOX/CXCL16 and CXCR6 plays an important role in enhancing T(CM) cell responses by mature DCs in lymphoid tissues and in augmenting T(EM) cell responses by macrophages in peripheral inflamed tissues.
authors.affiliation: Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Sumie
authors.initials: S
authors.lastname: Tabata
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Kadowaki
authors.forename: Toshio
authors.initials: T
authors.lastname: Kitawaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimaoka
authors.forename: Shin
authors.initials: S
authors.lastname: Yonehara
authors.forename: Osamu
authors.initials: O
authors.lastname: Yoshie
authors.forename: Takashi
authors.initials: T
authors.lastname: Uchiyama
mesh_terms: D017951:Antigen Presentation; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002450:Cell Communication / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D000075743:Chemokine CXCL16; D019743:Chemokines, CXC / Q000378:metabolism*; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D000075744:Receptors, CXCR6; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism*; D051116:Receptors, Scavenger; D011991:Receptors, Virus / Q000378:metabolism*
chemical_list: C423727:CXCL16 protein, human; C106330:CXCR6 protein, human; D000075743:Chemokine CXCL16; D019743:Chemokines, CXC; D008565:Membrane Proteins; D000075744:Receptors, CXCR6; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine; D043562:Receptors, G-Protein-Coupled; D011971:Receptors, Immunologic; D051116:Receptors, Scavenger; D011991:Receptors, Virus