Stimulation of Peripheral Blood and Intestinal Mucosa Cells by Synthetic CpG Oligodeoxynucleotides Fabrice Jugde ´, Christine Boissier, Brigitte Birebent, Nicolas Vu, Pierre-Nicolas D’halluin, Nathalie Rioux-Leclercq, Jean-Franc ¸ois Bretagne, Gilbert Semana, and Denis Heresebach ABSTRACT: The breakdown of tolerance to autologous bacterial flora has been implicated as a major factor con- tributing to the initiation and perpetuation of chronic inflammation in inflammatory bowel diseases (IBD). To test whether bacterial DNA is at the origin of inflamma- tion in IBD, we have examined the response of lamina propria (LPMC) or peripheral mononuclear cells (PBMC) and purified T cells from IBD patients and control pa- tients to stimulations with a set of oligodeoxynucleotides (ODNs) characterized by the presence or absence of cy- tosine-guanosine dinucleotides (CpG) and/or 3' poly- guanosine (poly-G) extension. Furthermore we have eval- uated the costimulatory activities of these ODNs on T cells activated via CD2 or CD3 pathway. We demon- strated that CpG ODNs induce higher proliferation of LPMC from inflammatory intestinal mucosa compared to healthy mucosa. We confirmed that CpG ODNs do not directly costimulate peripheral blood T cells activated by CD3 pathway. Finally, we revealed that CpG or non-CpG ODNs with 3' poly-G extension inhibit completely CD2 activation of purified PB or LP T-cells whereas only CpG ODNs without poly-G extension enhance proliferation and IFN- production of PB T cells stimulated by CD2 pathway only in presence of NK and NK T cells. Our data suggest that NK T cells may be the primary target of ODNs and play a crucial role in indirect T-cell activation by ODN. Human Immunology 65, 218-230 (2004). © American Society for Histocompatibility and Immunoge- netics, 2004. Published by Elsevier Inc. KEYWORDS: T-cell activation; CpG oligodeoxynucle- otides; inflammatory bowel disease; CD2 pathway ABBREVIATIONS APC antigen presenting cells CD Crohn’s disease CDI cell division index CFSE 5,6-carboxyfluorescein diacetate succinimidyl ester CpG cytosine-guanosine dinucleotides DTT dithiothreitol IBD inflammatory bowel disease IL-1R interleukin-1 receptor LPMC lamina propria mononuclear cells LPS lipopolysaccharide LPT-LKW lamina propria T cells, NK cells, and NK T cells LPT-MIL lamina propria T-cells MACS magnetically activated cell sorting NF-B nuclear factor B NK natural killer ODN oligodeoxynucleotides PAMP pathogen associated molecular patterns PBT-LKW peripheral blood T cells, NK cells, and NK T cells PBT-MIL peripheral blood T cells PDC plasmacytoid dendritic cells Poly-G poly-guanosine SOCS-1 suppressor of cytokine signaling-1 STAT1 signal transducer and activator of transcription 1 TCR T-cell receptor TLR toll-like receptor TNF tumor necrosis factor UC ulcerative colitis From the Laboratoire Universitaire d’Immunologie (F.J., C.B., B.B., N.V., G.S., D.H.), Universite ´ de Rennes; EFS Bretagne (B.B., G.S.), Rennes; Service des Maladies de l’Appareil Digestif (P.-N.D’H., J.-F.B., D.H.), CHU Pontchaillou, Centre d’e ´tude des maladies digestives de Rennes; Service d’Anatomie Pathologique B (N.R.-L.), Ho ˆpital Pontchaillou, Rennes, France. Address reprint requests to: Dr. Denis Heresbach, Service des Maladies de l’Appareil Digestif, Ho ˆpital Pontchaillou, Rue Henri Le Guilloux, 35033 Rennes Cedex, France; Tel: +33 (2) 99 28 43 47; Fax: +33 (2) 99 28 41 89; E-mail: denis.heresbach@chu-rennes.fr. Received September 12, 2003; revised December 30, 2003; accepted December 31, 2003. Human Immunology 65, 218-230 (2004) © American Society for Histocompatibility and Immunogenetics, 2004 0198-8859/04/$–see front matter Published by Elsevier Inc. doi:10.1016/j.humimm.2003.12.013