MD-PhD student Lausanne University Hospital and University of Lausanne Lausanne, Vaud, Switzerland
Abstract Text:
Background: In celiac disease, HLA-DQ2.5 facilitates the presentation of deamidated gluten-derived peptides to antigen-specific CD4+ T-cells, triggering immune activation and enteropathy. The adoptive transfer of engineered (e) gluten-specific regulatory T-cells (Tregs) may suppress the effector function of pathogenic T cells.
Methods: Five TCRs recognizing the immunodominant DQ2.5-glia-a1a(clones S2, LS2.8) and glia-a2 epitopes (clones D2, JR5.1, S16) were tested in a TCR-deficient NFAT-luciferase cell line. We next replaced the endogenous TCR of human primary T-cells and Tregs through homology-directed repair targeting the TCR alpha and beta constant loci using AAV and CRISPR-Cas9 technologies. The same strategy was applied to murine T-cells and Tregs, and evaluated in HLA-DQ2.5+ C57BL/6 transgenic mice exposed to gliadin via oral gavage.
Results: Jurkat cells transfected with the mRNA of any of the five gluten-specific TCRs exhibited peptide-specific NFAT activity. Human primary eCD4+ T cells upregulated CD25 and CD71 with a similar mean functional avidity (EC50) for either specific peptides but not for glia-a1a/a2 overlapping epitopes. Human eTregs demonstrated superior suppressive activity compared to polyclonally expanded Tregs in an EC50-dependent manner. In the HLA-DQ2.5 mouse model, eCD4+ T-cells migrated and strongly proliferated in the small intestine (duodenum/jejunum/ileum) and to a lesser extent in the draining (liver/celiac/duodenal/mesenteric) lymph nodes compared to the spleen. This proliferation was suppressed only in the presence of gluten-specific eTregs.
Conclusion: Redirecting Tregs to a single immunodominant gliadin-derived peptide could be sufficient for selective trafficking into the gut and draining lymph nodes. These cells hold therapeutic potential for restoring gluten tolerance in celiac patients.
