Anti-interferon-inducible chemokine, CXCL10, reduces colitis by impairing T helper-1 induction and recruitment in mice

Background: Colitis in interleukin (IL)-10^-/- mice is a CD4 ⁺ T helper 1 (T_H1)-mediated disease characterized by intermittent, transmural inflammation reminiscent of human Crohn's disease. In this study, we investigated the hypothesis that production of the CXC chemokine CXCL10 (interferon [IFN]γ-inducible protein 10) enhances induction of inflammatory responses in draining lymph nodes (LNs) and promotes colonic T _H1 cell recruitment. Methods: Colitis was induced in B6 IL-10 ^-/- mice. Mice were given anti-CXCL10 mAb in 2-week intervals before and after peak colitis. Colitis severity was graded and cytokine/chemokine levels were analyzed by real-time polymerase chain reaction. Cell yields were quantitated and effector cell recruitment was assessed by recovery of transferred DO 11.10 T_H1 cells shortly (72 h) after transfer. Results: Treatment with anti-CXCL10 during colitis development decreased clinical and histologic disease severity as well as cytokine/chemokine mRNA and accumulation of mononuclear cells in LNs and colon. Treatment of mice with severe colitis reduced colitis scores and cell yields to lesser degrees. Anti-CXCL10 specifically decreased recruitment of transferred T_H1 cells into mesenteric LNs (MLNs) and colon of IL-10^-/- mice by 75% (P < 0.05). Conclusion: These results suggest that CXCL10 plays a dual role in colitis development by enhancing T_H1 cell generation in inductive sites and promoting effector cell recruitment to inflamed tissue. Blockade of CXCL10 may be a useful adjunct to remission-inducing therapies in inflammatory bowel disease (IBD) by impairing disease recurrence through selective inhibition of effector cell generation and trafficking in vivo.