CD43 Signals Prepare Human T Cells to Receive Cytokine Differentiation Signals A.O. GALINDO-ALBARRA ´ N, 1 O. RAMI ´ REZ-PLIEGO, 1 R.G. LABASTIDA-CONDE, 1 E.I. MELCHY-PE ´ REZ, 3 A. LIQUITAYA-MONTIEL, 1 F.R. ESQUIVEL-GUADARRAMA, 2 G. ROSAS-SALGADO, 2 Y. ROSENSTEIN, 3 AND M.A. SANTANA 1 * 1 Facultad de Ciencias, Universidad Aut onoma del Estado de Morelos, Cuernavaca, Morelos, Mexico 2 Facultad de Medicina, Universidad Aut onoma del Estado de Morelos, Cuernavaca, Morelos, Mexico 3 Instituto de Biotecnolog  ıa, Universidad Nacional Aut onoma de M exico, Cuernavaca, Morelos, Mexico T cells are increasingly used for passive immunotherapy and bone marrow transplantation. Proper ex-vivo management of the cells is important for the desired therapeutic effects. For differentiation into effector cells of the Th1 and Th2 phenotypes, T-cells require signals from IFNg and IL-4, respectively. Na € |ve cells have an extremely low expression of the specific receptors that recognize these cytokines, indicating that in order to differentiate, cells need to perceive other signals that will enable them to sense the cytokine milieu. CD43 has been proposed as one of the molecules that make the initial contacts with antigen presenting cells. We report here that in cord blood, adult na € |ve and total human T cells, CD43 signals induced the expression of both IFNg and IL-4 receptors, mediate their capping, increased their signaling and augmented differentiation mediated by these receptors. CD43 signals also stimulated the expression of IFNg and in neonatal cells that of IL-4 as well. These data demonstrate an important role for CD43 signals in T-cell preparedness for differentiation into effector cells. J. Cell. Physiol. 229: 172–180, 2014. ß 2013 Wiley Periodicals, Inc. The priming of T-cells by antigen presenting cells (APCs) in the lymph nodes involves three distinctive stages (Mempel et al., 2004). During the first stage, T-cells make brief and abundant contacts with the APCs, scanning for potential antigens, and getting the first activation signals. In the second stage, the cells that recognize a specific antigen remain attached to APCs in a long lasting interaction that involves the formation of the immunological synapse, a key structure that is the site for exchange of signal and effector molecules between the cells in contact and for signal ending (Dustin and Depoil, 2011). The distribution of proteins due to synapse formation leads to an asymmetrical cell division that will influence the differentiation outcome of the cells (Littman and Singh, 2007). Finally, the cells separate and again brief interactions with other APCs precede their exit from lymph nodes. The nature of the first contacts is only partially known. In murine T-cells, antigen-independent contacts between CD4 þ T cells and APCs are sufficient to trigger mild activation and survival signals (Revy et al., 2001). In addition to the antigen specificity provided by the TCR, other surface molecules have been implicated in the first activation steps and in strengthening the T cell-APC interaction (Stockl et al., 1996; Dustin, 2004; van Gisbergen et al., 2005). CD43 is a large, abundant and heavily glycosylated molecule that protrudes 45 nm from the cell membrane (Cyster et al., 1991). This transmembrane Type I mucin-like molecule has been proposed as one of the first molecules to make contact with APCs, regulating cell adhesion and function (Sanchez-Mateos et al., 1995; Miura et al., 2001; Tong et al., 2004; Fierro et al., 2006) as well as T cell traffic (Cannon et al., 2011). Interaction between CD43 and MHC I, augments spontaneous conjugate formation between T cells and APCs (Cyster and Williams, 1992; Stockl et al., 1996) through a process that involves an increase in expression and affinity of CD2 for its ligand CD58. Signals transduced through CD43 lead to cell activation, proliferation and survival (Rosenstein et al., 1999; Fierro et al., 2006). Its extracellular domain can be processed by g-secretase, allowing the accumulation of CD43 cytoplasmic domain in promyelocitic nuclear bodies, control- ing the sensitivity to apoptosis, and cell proliferation (Seo and Ziltener, 2009). CD43 also functions as a TCR accessory molecule, lowering the threshold for T cell-activation, through the inhibition of c-cbl negative signals (Pedraza-Alva et al., 2011), inducing the activation of AP1, NFkB and NFAT transcription factors (Santana et al., 2000). In addition, we and others have evidenced a role for CD43 in Th1 differentiation (Ramirez-Pliego et al., 2007; Cannon et al., 2008). Herein we evaluated the effect of CD43 signals on three maturational stages of human T cells: neonatal cells, rich in recent thymus emigrants (RTE), a distinctive maturational stage that precedes mature na € |ve cells (Fink and Hendricks, 2011; Houston et al., 2011), na € |ve adult T cells, and total circulating T cells (considered to comprise about 45% of memory cells). In all cases, CD43 signals induced an increase in: the surface expression of IFNg and IL-4 receptors, the co-capping of IFNgR with the TCR, the phosphorylation of STAT1 and Contract grant sponsor: CONACYT. Contract grant sponsor: DGAPA/UNAM. Contract grant sponsor: PROMEP. *Correspondence to: M.A. Santana, Facultad de Ciencias, Universidad Aut onoma del Estado de Morelos, Av. Universidad 1001, Chamilpa, Cuernavaca, Morelos, Mexico. E-mail: santana@uaem.mx Manuscript Received: 27 November 2012 Manuscript Accepted: 3 July 2013 Accepted manuscript online in Wiley Online Library (wileyonlinelibrary.com): 9 July 2013. DOI: 10.1002/jcp.24430 ORIGINAL RESEARCH ARTICLE 172 Journal of Journal of Cellular Physiology Cellular Physiology ß 2013 WILEY PERIODICALS, INC.