RESEARCH ARTICLE IL-10 gene therapy prevents TNBS-induced colitis J Lindsay 1 , C van Montfrans 2 , F Brennan 1 , S van Deventer 2 , P Drillenburg 3 , H Hodgson 4 , A te Velde 2 and M Sol Rodriguez Pena 2 1 The Kennedy Institute of Rheumatology, Imperial College School of Medicine, London, UK; 2 Department of Internal Medicine, Academic Medical Centre, Amsterdam, The Netherlands; 3 The Department of Pathology, Academic Medical Centre, Amsterdam, The Netherlands; and 4 The Department of Hepatology, Royal Free & University College Medical School, London, UK The transfer of genes encoding immunomodulatory proteins to the intestinal mucosa is a promising new approach to the treatment of Crohn’s disease (CD). This study investigates the therapeutic efficacy of an adenoviral vector encoding IL- 10 (AdvmuIL-10) in experimental colitis. BALB/c mice were treated with a single intravenous injection of AdvmuIL-10, empty cassette virus (Adv0) or PBS prior to the induction of trinitrobenzene sulphonic acid (TNBS) colitis. AdvmuIL-10 treatment prevented the severe loss of body weight associated with TNBS administration. In addition, AdvmuIL- 10 therapy led to a significant reduction in both stool markers of inflammation (IL-1b and TNFR-II) and acute phase response (serum amyloid protein). Finally, the histological scores of mice with TNBS colitis treated with AdvmuIL-10 were significantly lower than Adv0- or PBS-treated controls. The therapeutic efficacy of AdvmuIL-10 was associated with a decrease in the IFN-g and IL-6 levels detected in colonic homogenates from mice with TNBS colitis, whereas no effect was observed on cytokine release from stimulated systemic lymphocytes. Thus, AdvmuIL-10 is an effective therapy in the TNBS model of colitis. Gene therapy strategies using adenoviral vectors encoding IL-10 may prove to be a potent therapy for chronic inflammatory conditions such as CD. Gene Therapy (2002) 9, 1715–1721. doi:10.1038/sj.gt.3301841 Keywords: interleukin-10; colitis; gene therapy Introduction Studies of IL-10 deficient (IL-10 À/À ) and IL-10 receptor-2 deficient mice show that these mice develop a T helper (Th)-1-mediated intestinal inflammation and indicate that IL-10 is an important regulatory cytokine within the mucosal immune system. 1,2 The activity of IL-10 in counter regulating mucosal inflammation is likely to be multifactorial. IL-10 is a potent down regulator of IL-12 production and thus acts at the level of Th1 cell induction. 3 In addition, IL-10 suppresses the production of other pro-inflammatory cytokines and chemokines including TNF-a IL-1b, IL-6 and IL-8. 4 Finally, there is substantial evidence that IL-10 acts both to promote the differentiation and augment the activity of regulatory T cells. 5–8 The observations in IL-10 À/À mice have laid the foundation for therapeutic trials of IL-10 in several other models of colitis. These studies have shown that systemic IL-10 administration is able to prevent intestinal inflam- mation by down regulating the intestinal pro-inflamma- tory Th1 response. 1,9,10 Based on these successful experimental findings, recombinant (r)IL-10 was admi- nistered by subcutaneous injection to patients with either mild/moderate or steroid refractory Crohn’s disease, as well as in patients undergoing ileal resection to prevent postoperative recurrence. 11–13 Although the data indi- cated that systemic rIL-10 therapy is safe and well tolerated, this therapy resulted in only a modest response in steroid naı ¨ve patients, and no significant benefit compared to placebo in steroid refractory patients. Explanations for this lack of efficacy include the short half-life of rIL-10, 14 local delivery of insufficient amounts of rIL-10 to inhibit mucosal Th1 responses and the side effects associated with high-dose rIL-10. 15 Sustained IL-10 delivery may prove more effective than daily systemic injections. Indeed, daily intra-gastric administration of IL-10-secreting Lactococcus lactis caused a 50% reduction in disease severity in mice with dextran sulphate sodium induced colitis and prevented the onset of colitis in IL-10 À/À mice. 16 Alternatively, adenoviral vectors could be used to deliver the IL-10 gene and secure constant expression of high levels of IL-10 within the gastro-intestinal tract. Adenoviral vectors can infect intestinal epithelial cells with high efficiency 17 and after intravenous administration they target the liver and the spleen, but also the colon. 18,19 Adenoviral transfer of IL- 10 has been shown to be beneficial in murine experi- mental arthritis, another Th1-mediated disease. 20–22 Finally, we have recently demonstrated the efficacy of adenovirus-mediated IL-10 gene transfer in the treatment of established colitis in IL-10 À/À mice. 23 In the present study, we have investigated the therapeutic efficacy of mIL-10 adenovirus-mediated (AdvmuIL-10) gene transfer in murine 2,4,6-trinitroben- zene sulphonic acid (TNBS) colitis, which has many histological and immunological similarities to Crohn’s disease, and is also relatively unresponsive to daily systemic injections of recombinant IL-10. 24 Intra-rectal TNBS administration induces a transmural colitis, which Received 24 March 2002; accepted 25 June 2002 Correspondence: J Lindsay, The Kennedy Institute of Rheumatology Division, Imperial College School of Medicine, 1 Aspenlea Road, London W6 8LH, UK The first two authors contributed equally to this work Gene Therapy (2002) 9, 1715–1721 & 2002 Nature Publishing Group All rights reserved 0969-7128/02 $25.00 www.nature.com/gt