Figure 5: Treg with impaired IL-15 signaling fail to prevent colitis in RAG2ko hosts injected with both Treg and naive CD4+ T cells.
From: IL-15-dependent balance between Foxp3 and RORγt expression impacts inflammatory bowel disease
(a) Treg (CD4+Foxp3+RORγt−) and naive CD4+ T lymphocytes (CD4+Foxp3-CD62LhiCD45RBhi ) were sorted from Foxp3-mRFP × RORγt–GFP and from IL-15Rαko × Foxp3-mRFP × RORγt–GFP mice. About 105 IL-15Rαko Treg cells were injected together with 105 IL-15-competent naive CD4+ T cells into RAG2ko mice. Similarly, 105 IL-15Rαko naive CD4+ were injected together with 105 IL-15-competent Treg cells into other group of RAG2ko mice. Recipient mice were killed 8 weeks later. (b) Body weight curve of recipient RAG2ko, which received IL-15Rαko Treg and WT CD4+ T cells (grey line) and of RAG2ko mice injected with IL-15Rαko CD4+ and WT Treg cells (black line). (c) Histological scores (from 0—minimal to 5—severe) of microscopic changes in the colon of RAG2ko mice following transfer of IL-15Rαko Treg and WT CD4+ T cells (black bars) and RAG2ko following transfer of IL-15Rαko CD4+ and WT Treg cells (white bars). The score values for the second group are 0, therefore they are not visible 8 weeks post transfer. All graphs indicate mean values; error bars denote s.e.m. (d) Haematoxylin and eosin-stained sections of colons from RAG2ko mice after naive CD4+/Treg T-cell transfer. Original magnification: upper panel × 4 (scale bar, 250 μm), bottom panel × 10 (scale bar, 100 μm). (a–d) Data compiled from two separate experiments with at least three mice per group.
