TGF-1 Reciprocally Controls Chemotaxis of Human Peripheral Blood Monocyte-Derived Dendritic Cells Via Chemokine Receptors Katsuaki Sato, 1 * Hiroshi Kawasaki, 1² Hitomi Nagayama,* Makoto Enomoto,* Chikao Morimoto, ² Kenji Tadokoro, ‡ Takeo Juji, ‡ and Tsuneo A. Takahashi 2 * We examined the effect of TGF-1 on the chemotactic migratory ability of human monocyte-derived dendritic cells (DCs). Treatment of immature DCs with TGF-1 resulted in increased expressions of CCR-1, CCR-3, CCR-5, CCR-6, and CXC che- mokine receptor-4 (CXCR-4), which were concomitant with enhanced chemotactic migratory responses to their ligands, RANTES (for CCR-1, CCR-3, and CCR-5), macrophage-inflammatory protein-3 (MIP-3) (for CCR-6), or stromal cell-derived growth factor-1 (for CXCR-4). Ligation by TNF- resulted in down-modulation of cell surface expressions of CCR-1, CCR-3, CCR-5, CCR-6, and CXCR-4, and the chemotaxis for RANTES, MIP-3, and stromal cell-derived growth factor-1, whereas this stim- ulation up-regulated the expression of CCR-7 and the chemotactic ability for MIP-3. Stimulation of mature DCs with TGF-1 also enhanced TNF--induced down-regulation of the expressions of CCR-1, CCR-3, CCR-5, CCR-6, and CXCR-4, and chemo- taxis to their respective ligands, while this stimulation suppressed TNF--induced expression of CCR-7 and chemotactic migratory ability to MIP-3. Our findings suggest that TGF-1 reversibly regulates chemotaxis of DCs via regulation of chemokine receptor expression. The Journal of Immunology, 2000, 164: 2285–2295. D endritic cells (DCs) 3 are unique professional major APCs capable of stimulating resting T cells (TCs) in primary immune responses, and are more potent APCs than peripheral blood monocytes/macrophages or B cells (1). DCs also play major roles in autoimmune diseases, graft rejection, HIV infection, and the generation of TC-dependent Abs (1– 4). DCs capture and process Ag in nonlymphoid tissues and then migrate to TC-dependent areas of secondary lymphoid organs via afferent lymph or the bloodstream to prime native TCs and initiate immune responses (5, 6). Characterization of DCs is difficult because they represent only a small subpopulation that includes interdigitating reticulum cells in lymphoid organs, blood DCs, Langerhans cells in the epidermis of the skin, and dermal DCs (1). Previously, an in vitro culture system revealed that DCs originate from CD34 + pluripotent he- mopoietic progenitor cells (HPCs) in the bone marrow (BM) and cord blood via myeloid lineage cells in human and murine models (7–16), and some DCs develop from thymic precursors via lym- phoid lineage cells in murine system (17). Chemokines are extensively involved in inflammatory/immuno- logical responses due to their unique ability to recruit selective leukocyte subsets (18). Chemokines have been implicated in reg- ulation of normal leukocyte recirculation and homing, and also in certain physiological and pathogenic processes, including hemo- poiesis, angiogenesis, allergy, autoimmune diseases, and viral in- fectious diseases (18). Chemokines are a group of 70 –90 amino acids, structurally related polypeptides, most of which contain four conserved cysteine residues in their primary amino acid sequence (18). There are two major groups: the CXC chemokines in which the two NH 2 -terminal cysteines are separated by a single amino acid, and the CC chemokines, in which the two NH 2 -terminal cys- teines are adjacent. A third type of chemokine, represented by lym- photactin, contains only two of the four conserved cysteines (18). The specific effects of chemokines on the target cell types are mediated by a family of single-chain, seven-helix membrane-span- ning receptors coupled to heterotrimeric guanine nucleotide-bind- ing protein (G protein) (GPCR), which consists of a Gi,G, and G subunit complex (18). Ligand specificities of 14 chemokine receptors have been identified; five of the receptors are specific for CXC chemokines (CXCR1–5) (18), eight of them are specific for CC chemokines (CCR1–8) (18–20), and the Duffy Ag receptor binds both CXC and CC chemokines (21). In addition, distinct che- mokines appear to act on more than one receptor type in vitro (18). There is increasing interest in the potential role of chemokines and their respective receptors in the biological properties of DCs to clarify the mechanism underlying DC-mediated regulation of im- mune/inflammatory responses. Previous studies have shown that several chemokine receptors are expressed on some DCs and their progenitor cells at the transcriptional level (22–27). Recent studies have shown that the chemotactic migratory properties in response to certain chemokines are strictly regulated in the development of DCs from their progenitor cells, and these regulatory mechanisms have been potentially implicated in mediating the trafficking of DCs and their progenitor cells from blood to tissues and then to Departments of *Cell Processing and ² Clinical Immunology and AIDS Research Cen- ter, Institute of Medical Science, University of Tokyo, Tokyo, Japan; and ‡ Japanese Red Cross Central Blood Center, Tokyo, Japan Received for publication August 23, 1999. Accepted for publication December 13, 1999. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 1 K.S. and H.K. contributed equally to this study. 2 Address correspondence and reprint requests to Dr. Tsuneo A. Takahashi, Depart- ment of Cell Processing, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan. E-mail address: takahasi@ims.u.- tokyo.ac.jp 3 Abbreviations used in this paper: DC, dendritic cell; BM, bone marrow; CXCR, CXC chemokine receptor; FITC-DX, FITC labeled-dextran; HPC, hemopoietic pro- genitor cell; iDC, immature DC; LY, lucifer yellow; mDC, mature DC; MFI, mean fluorescence intensity; MIP, macrophage-inflammatory protein; SDF, stromal cell- derived factor; TC, T cell. Copyright © 2000 by The American Association of Immunologists 0022-1767/00/$02.00