ORIGINAL RESEARCH PAPER Lymphocytes modulate peritoneal leukocyte recruitment in peritonitis T. Kipari Æ S. Watson Æ K. Houlberg Æ S. Lepage Æ J. Hughes Æ Jean-Franc ¸ois Cailhier Received: 7 August 2008 / Revised: 6 January 2009 / Accepted: 10 February 2009 / Published online: 5 March 2009 Ó Birkha ¨user Verlag, Basel/Switzerland 2009 Abstract Objective and design To investigate the modulating role of lymphocytes in leukocyte recruitment in a murine model of peritonitis. Materials or subjects RAG-1 knockout (KO) mice, NUDE mice and lMT KO mice were compared to their wild-type controls. Treatment Mice were administered with 1 ml of Brew- er’s thioglycollate (BTG) and terminal peritoneal lavages were performed at 8, 24, 72 and 120 h after treatment. Methods Leukocyte numbers recruited at the different time points following a BTG administration were deter- mined. Chemokine and cytokine levels were assessed by either ELISAs or cytometric bead array. Results RAG-1 KO mice (absent B and T cells) exhibited increased early neutrophil infiltration and blunted late monocyte/macrophage infiltration. NUDE mice (absent T cells) exhibited both increased neutrophil and monocyte/ macrophage infiltration. In contrast, lMT KO mice (absent B cells) demonstrated reduced influx of both neutrophils and monocyte/macrophages. Chemokine analysis revealed various differences in important chemokines. Conclusions These data suggest that T cells act to sup- press leukocyte recruitment while B cells promote leukocyte recruitment. Keywords Lymphocytes Á Experimental peritonitis Á Lymphocyte deficient mice Á Leukocyte recruitment Á Chemokines Introduction The orchestration of inflammatory responses in the peri- toneum is complicated and may involve many cells including resident macrophages (M/), mast cells and the mesothelial cells that line the peritoneal cavity. Our pre- vious work indicated that resident peritoneal and pleural M/ play a critically important role in the orchestration of neutrophil (PMN) recruitment in various models of peri- toneal and pleural inflammation [1, 2]. However, the peritoneal space contains many lymphocytes in addition to resident peritoneal M/ with lymphocytes representing nearly 50% of resident peritoneal leukocytes in humans [3] and approximately 14% of resident peritoneal leukocytes in mice although there are variations between strains [4]. There are scant data available regarding the function of lymphocytes during the initiation of acute peritoneal inflammation [5]. Recent work by Kolaczkowska et al. [6] demonstrated comparable changes between RAG- deficient mice and wild-type mice in vascular permeability and PMN infiltration in the model of zymosan peritonitis at the 30 min and 6 h time points, respectively [6]. In contrast, work by Rajakaria et al. [7] demonstrated that Responsible Editor: G. R. Wallace. J. Hughes and J.-F. Cailhier are joint senior authors. T. Kipari Á S. Watson Á K. Houlberg Á J. Hughes Phagocyte Laboratory, MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK S. Lepage Á J.-F. Cailhier (&) Research Centre, Centre Hospitalier de l’Universite ´ de Montre ´al (CHUM), Pavillon JA DeSeve, Y-4622, 2099 Alexandre DeSeve Street, Montreal, QC H2L 4M1, Canada e-mail: jf.cailhier@umontreal.ca S. Lepage Á J.-F. Cailhier Montreal Cancer Institute, Universite ´ de Montre ´al, Montreal, QC, Canada Inflamm. Res. (2009) 58:553–560 DOI 10.1007/s00011-009-0019-5 Inflammation Research