Modeling intestinal Graft-versus-Host Disease using IFNγ-damaged organoids to characterize T cell behavior

Graft-versus-Host Disease (GvHD) is a life-threating immune disorder that follows hematopoietic cell transplantation. GvHD is characterized by the activation of donor immune cells targeting the recipient's healthy tissues. One of the inflammatory cytokines mediating GvHD is IFNγ, which is mainly produced by T cells among other immune cells. Our study explores the effect of IFNγ-induced epithelial damage on T cell behavior using a 3D model based on intestinal organoids. Preliminary data demonstrated increased migration of T cells towards IFNγ-treated intestinal organoids. Proteomic analysis of conditioned media revealed increased CXCL9, CXCL10, and CXCL11 released by treated organoids. To unravel the role of these molecules in T cell migration, we neutralized each chemokine using specific monoclonal antibodies. Our results demonstrated that only CXCL11 mediates T cell migration towards damaged organoids, with most migrating T cells expressing CXCR3 but not CXCR7. Additionally, we explored the impact of organoid-derived Galectin-9 (Gal-9, encoded by LGALS9), as IFNγ-treated organoids release this molecule. We generated a LGALS9-knockout organoid line and examined T cell behavior, suggesting an immunostimulatory effect of Gal-9 independent of the treatment with IFNγ. In conclusion, we propose a potential role for CXCL11 in intestinal GvHD by recruiting CXCR3+ T cells to the inflamed intestine.