Transcriptional Reprogramming of Mature CD4 T helper Cells generates distinct MHC class II restricted Cytotoxic T Lymphocytes

We show here that the T helper-fate is not fixed and that mature antigen-stimulated CD4 T cells can switch off Thpok expression and reactivate CD8- lineage genes. This unexpected plasticity results in the post-thymic termination of the T helper- program and the functional differentiation of distinct MHC class II restricted CD4 cytotoxic T lymphocytes Small intestine CD4 intraepithelial T lymphocytes from ThPOK-GFP reposter mice were isolated and sorted (FACS Aria) based on ThPOK and CD8aa expression. Cell were isolated either from non-experimental ThPOK-GFP reporter mice (WT) or after transfering CD4 naive T cells from ThPOK-GFP reporter mice to RAG-/-recipient animals (TR) as an experimental colitis model. Experimet was done in duplicate.