CD152 (CTLA-4) Determines CD4 T Cell Migration In Vitro and In Vivo Karin Knieke1,2, Holger Hoff2, Frank Maszyna2, Paula Kolar2, Arnhild Schrage2, Alf Hamann 2 , Gudrun F. Debes3, Monika C. Brunner-Weinzierl1,2* 1 Experimentelle Pa¨diatrie, Universita¨tskinderklinik – Otto-von-Guericke Universita¨t, Magdeburg, Germany, 2 Deutsches Rheuma-Forschungszentrum Berlin and Medizinische Klinik mit Schwerpunkt Rheumatologie und Klinischer Immunologie, CCM, Charite´ -Universita¨tsmedizin Berlin, Berlin, Germany, 3 Department of Pathobiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America Abstract Background: Migration of antigen-experienced T cells to secondary lymphoid organs and the site of antigenic-challenge is a mandatory prerequisite for the precise functioning of adaptive immune responses. The surface molecule CD152 (CTLA-4) is mostly considered as a negative regulator of T cell activation during immune responses. It is currently unknown whether CD152 can also influence chemokine-driven T cell migration. Methodology/Principal Findings: We analyzed the consequences of CD152 signaling on Th cell migration using chemotaxis assays in vitro and radioactive cell tracking in vivo. We show here that the genetic and serological inactivation of CD152 in Th1 cells reduced migration towards CCL4, CXCL12 and CCL19, but not CXCL9, in a G-protein dependent manner. In addition, retroviral transduction of CD152 cDNA into CD152 negative cells restored Th1 cell migration. Crosslinking of CD152 together with CD3 and CD28 stimulation on activated Th1 cells increased expression of the chemokine receptors CCR5 and CCR7, which in turn enhanced cell migration. Using sensitive liposome technology, we show that mature dendritic cells but not activated B cells were potent at inducing surface CD152 expression and the CD152-mediated migration-enhancing signals. Importantly, migration of CD152 positive Th1 lymphocytes in in vivo experiments increased more than 200% as compared to CD152 negative counterparts showing that indeed CD152 orchestrates specific migration of selected Th1 cells to sites of inflammation and antigenic challenge in vivo. Conclusions/Significance: We show here, that CD152 signaling does not just silence cells, but selects individual ones for migration. This novel activity of CD152 adds to the already significant role of CD152 in controlling peripheral immune responses by allowing T cells to localize correctly during infection. It also suggests that interference with CD152 signaling provides a tool for altering the cellular composition at sites of inflammation and antigenic challenge. Citation: Knieke K, Hoff H, Maszyna F, Kolar P, Schrage A, et al. (2009) CD152 (CTLA-4) Determines CD4 T Cell Migration In Vitro and In Vivo. PLoS ONE 4(5): e5702. doi:10.1371/journal.pone.0005702 Editor: Fu-Sheng Wang, Beijing Institute of Infectious Diseases, China Received June 30, 2008; Accepted April 29, 2009; Published May 27, 2009 Copyright: 2009 Knieke et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The study was funded by the Gemeinn u¨tzige Hertie Stiftung (1.01.1/05/003), Doktor Robert Pfleger-Stiftung and the DFG (BR1860 and SFB650, TP8). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of this manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: monika.brunner-weinzierl@med.ovgu.de Introduction The positioning of differentiated effector/memory T cells within tissues is important for the adaptive immune responses to ensure protection against reinfection. Chemokines and their receptors are essential for homing of antigen-experienced T cells to lymphoid and non-lymphoid destinations [1,2]. The signals responsible for the chemokine-directed migration of certain T cell subsets remain poorly characterized. Following initial activation, na¨ıve CD4+ T cells can differentiate into Th1 cells that secrete pro-inflammatory cytokines such as IFN- c and TNFa, and induce cell-mediated immune responses [3]. Th1 responses are critical for the eradication of intracellular pathogens such as Leishmania major and Listeria monocytogenes. However, Th1 responses also drive chronic inflammation and tissue destruction in autoimmune diseases such as multiple sclerosis, type I diabetes, Crohn’s disease, and rheumatoid arthritis [4–8]. Given the requirement for trafficking of effector T cells to diverse tissue sites in the body, it seems likely that there is substantial heterogeneity in the migratory capacity of Th cell subsets. CD28 and CD152 are the primary co-receptors on T cells that mediate positive and negative costimulation using the same ligands on APCs, CD80 and CD86. Triggering of CD28 strongly up- regulates IL-2 production and T cell proliferation, which is counter-regulated by CD152-mediated inhibition of IL-2 tran- scription and cell cycle progression [9]. CD152 does not only oppose CD28-mediated effects, but can also synergize with it, e.g. by enhancing resistance to apoptosis [10–13]. Thus, the role of CD152 is more complex than its traditional view as a major down- regulator of immune responses [9,14,15]. CD152 is inducible after stimulation of T cells and reaches maximal surface levels 48 h after T cell stimulation [16], when maximal CD152 function is observed. The regulation of CD152 surface expression represents a major control point for its function because only cell surface expressed CD152 is functional [11,16], and only a restricted number of activated T cells can express CD152. CD152 is PLoS ONE | www.plosone.org 1 May 2009 | Volume 4 | Issue 5 | e5702