Investigating the Role of Peripheral Regulatory T Cells in Oral Tolerance to Gluten in Celiac Disease 2259765

Abstract Introduction Celiac disease (CeD) is an immune-mediated enteropathy triggered by CD4+ T-cell recognition of gluten-derived peptides presented by HLA-DQ8, leading to chronic intestinal inflammation. Although regulatory T cells (Tregs) are central to mucosal tolerance, the relative contributions of thymus-derived Tregs (tTregs) versus peripherally induced Tregs (pTregs) remain unresolved. Here, we define the role of pTregs in gluten-driven inflammation using a transgenic mouse model that separates tTreg and pTreg function in the context of HLA-DQ8—restricted antigen presentation. Methods Mice: HLA-DQ8/I-Ab knockout (Ab⁻/⁻) mice were bred with CNS1-deficient (CNS⁻/⁻) mice, which lack pTreg generation, and Foxp3-GFP reporter mice. Four groups were defined by genotype (CNS⁻/⁻ vs. CNS+/+) and diet (gluten-free diet [GFD] vs. regular chow). Experimental designs: (1) Adoptive transfer of CD4+ T cells into TCRα⁻/⁻ recipients, followed by a diet switch. (2) Direct switch from GFD to regular chow. (3) Mucosal adjuvant model using cholera toxin (±gluten) with diet change. Readouts: Body weight and fecal lipocalin-2 were tracked as clinical and inflammatory markers. Immune profiling via flow cytometry was done on mesenteric lymph nodes, lamina propria, and intraepithelial lymphocytes (IELs). Results Across all study arms, CNS⁻/⁻ mice maintained on regular chow developed significant weight loss and elevated fecal lipocalin-2, indicating intestinal inflammation. Flow cytometry revealed increased frequencies of activated lymphocytes in CNS⁻/⁻ mice on regular chow compared with all other groups in different organs. Conclusion This novel mouse model provides a robust platform for studying the role of pTregs in gluten-induced tolerance and celiac disease—associated inflammation. The findings underscore the importance of pTregs in maintaining intestinal immune homeostasis and offer a valuable tool for future mechanistic and therapeutic investigations Funding Source Georgia State university intramural funding Topic Categories Mucosal and Regional Immunology (MUC)