P155 THERAPEUTIC EFFECT OF OPS-2071 ON HEALING OF T CELL-MEDIATED COLITIS, A MURINE MODEL OF CROHN’S DISEASE, WITH ANTI-INFLAMMATORY AND ANTIBACTERIAL ACTIVITY
Authors: Takagi Hiroko , Sato Masayoshi , Fujii Kazuyuki , Shibuya Isao , Oka Daisuke , Yamaya Naomitsu , Inagaki Katsuya 
Published: January 2020

Abstract

Background
Crohn’s disease (CD) is a form of chronic inflammatory bowel disease (IBD). Although CD is an immune-mediated condition of unknown etiology, many studies suggested that abnormal immune responses against certain intestinal bacteria may trigger development of chronic inflammation. The T cell-mediated colitis model is a well characterized adaptive transfer murine model of chronic small bowel and colonic inflammation that resembles human CD (e.g., diarrhea, a heavily inflamed colon, loss of mucus from goblet cells, Th1/Th17 dominated cytokine profile). OPS-2071, a novel agent synthesized by Otsuka Pharmaceutical Co., Ltd, has broad and strong antibacterial activity with low systemic absorption. In this study, we have evaluated the therapeutic effect of OPS-2071 on murine T cell-mediated colitis and in vitro activity on T cell activation, cytokine production and antibacterial activity.

Methods
T cell-mediated colitis was induced via naive T cell (CD4+CD62L+CD44-) injection into T and B cell deficient recipient mice. Two weeks following T cell transfer, OPS-2071 or vehicle solution was administered orally for 3 weeks, followed by harvesting of colon tissue and assessment of efficacy evaluation by histological score and inflammatory index (colon weight/ length). In vitro inhibitory action for TNF-α production was assayed by ELISA using LPS-stimulated human peripheral blood cells. The effect on T cell activation and cytokine production (TNF-α, IFN-γ), was examined using human peripheral blood mononuclear cells and, mouse spleen which were stimulated by anti-CD2/CD3/CD28 antibody-loaded beads. In vitro activity against bacteria considered to be the cause of IBD was also tested.

Results
In the murine T cell transfer model, OPS-2071 significantly reduced both histological score (control: 9.2, OPS: 2.7, p&lt;0.001) and inflammatory index (control: 54.7±2.2 mg/cm, OPS: 27.8±1.7 mg/cm, p&lt;0.001) at a dose of 10 mg/kg. In the in vitro experiments, OPS-2071 suppressed TNF-a production produced by LPS in human whole blood dose-dependently. OPS-2071 also suppressed human and mouse T cell activation and cytokine production and suppressed T cell proliferation. At high OPS-2071 concentrations, these effects were comparable to prednisolone. The Minimum Inhibitory Concentration against IBD related bacteria for OPS-2071, ciprofloxacin, and metronidazole were 0.015 - 0.5, 0.25 - 8, and 0.03 - &gt;128 mg/mL, respectively.

Conclusion
OPS-2071 demonstrated significant therapeutic effects on colon inflammation in the murine T cell-medicated colitis model, suppressed TNF-a production in vitro and showed in vitro activity against bacteria related to CD. The dual effect of anti-inflammatory effects and antibacterial activity of the novel agent OPS-2071 demonstrated in this study, provide rationale for exploring the impact of this compound on human CD in clinical trials.