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Inflammatory bowel diseases (IBD), mainly including Crohn's disease (CD) and ulcerative colitis (UC), are characterized by chronic, relapsing-remitting inflammation of the gastrointestinal tract, affecting millions worldwide1. Several factors have been implicated in the development and pathogenesis of IBD, including genetic susceptibility, gut microbiota, immune responses, diet, and lifestyle2. However, the exact mechanism of IBD is still not completely understood.
One of the particular interests is the interaction between gut microbiota and host immune responses in regulating intestinal inflammation3. Gut microbiota provides a series of immunostimulatory molecules and antigens, which can activate immune responses4. While the balance between effector T cells and regulatory T cells (Tregs) is critical in maintaining intestinal homeostasis, the excessive intestinal mucosal CD4+ T cell response to gut microbiota antigens contributes to intestinal inflammation5,6,7. As an immunodominant gut microbiota antigen, CBir1 flagellin has been related to the pathogenesis of human CD8,9. Furthermore, transfer of CBir1 TCR transgenic (Tg) T cells induces intestinal inflammation in immune-deficient mice6, closely resembling the human IBD, indicating that this T cell transfer model helps investigate the mechanisms of human IBD.
This work describes the detailed protocol of inducing colitis in Rag1-/- mice by adoptive transfer of CBir1 TCR Tg naϊve CD4+ T cells and assessing disease severity. Besides, the anticipated results are shown, and the critical steps of the procedure and troubleshooting are discussed, which will help researchers investigate the mechanisms of pathogenesis of intestinal inflammation and test the potential drugs for treating IBD.