Blockade of LTB4/BLT1 pathway improves CD8+ T‐cell‐mediated colitis

• Published in: Inflammatory bowel diseases Vol. 17; no. 1; pp. 279 - 288
• Main Authors: Nancey, Stephane, Boschetti, Gilles, Hacini, Feriel, Sardi, Fatima, Durand, Pierre‐Yves, Le Borgne, Maylis, Furhmann, Lydie, Flourie, Bernard, Kaiserlian, Dominique
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.01.2011
• Subjects: BLT1 antagonists; Body weight loss; CD8 antigen; CD8+ T cells; Colitis; Colon; Cytotoxicity; Data processing; Dendritic cells; endopeptidase; Enzyme-linked immunosorbent assay; Immunization; Inflammation; Inflammatory bowel diseases; Interferon; Intestine; Leukotriene B4; LTB4; Lymph nodes; Lymphocytes T; Lymphoid cells; Receptor mechanisms; Serine proteinase; T-cell receptor
• ISSN: 1078-0998; 1536-4844; 1536-4844
• DOI: 10.1002/ibd.21404

Background: Leukotriene B4 (LTB4) has chemotactic properties for activated T cells expressing the high‐affinity receptor BLT1. This study investigated whether the LTB4 antagonist (CP‐105,693), selective for BLT1 receptor, could protect mice from colitis mediated by specific cytotoxic CD8+ T lymphocytes (CTL). Methods: Virus‐specific colitis was induced in C57Bl/6 mice transferred with lymphoid cells from P14 TcR Tg mice which are specific to class I GP33 peptide of LCMV. Mice were immunized with GP33‐pulsed dendritic cells and colitis was elicited by intrarectal administration of the peptide. Colitis was evaluated by body weight loss and macroscopic and histological analysis of colon. In vivo priming of specific CD8+ CTL was determined using interferon (IFN)‐γ ELISPOT and in vivo CTL assays. In some experiments mice were treated with a selective LTB4 receptor antagonist. Results: Immunization with GP33‐pulsed dendritic cells (DCs) induced priming of specific CD8+ CTL, as shown by the presence of IFN‐γ‐producing CD8+ T cells in colon draining lymph nodes and in vivo CTL assays. Intrarectal challenge with GP33 induced severe colitis and recruitment of granzyme B+ P14 CD8+ cells in colon. Treatment with the specific LTB4 receptor antagonist before elicitation of colitis reduced the severity of colitis and decreased the frequency of specific effectors. Conclusions: Colitis can be induced by IFN‐γ‐producing cytotoxic CD8+ CTL specific for viral antigen. Blockade of the LTB4/BLT1 pathway by a selective BLT1 receptor antagonist attenuates colitis by inhibiting CD8+ effectors recruitment in colon. These data illustrate the therapeutic potential of LTB4 receptor selective antagonists in protection from CD8+ T‐cell‐mediated intestinal inflammation. (Inflamm Bowel Dis 2011;)