The invention relates to a nucleic acid encoding, an artificial T cell receptor, or a fragment of an artificial T cell receptor, wherein the nucleic acid is operatively linked to a transcriptional regulatory sequence, and wherein the transcriptional regulatory sequence comprises a binding domain for a transcription factor that promotes a regulatory T lymphocyte phenotype and cells comprising such nucleic acids. The cells may further comprise a nucleic acid encoding the transcription factor and a targeting polypeptide. The cells of the invention are useful in medicine, in particular in the treatment of inflammatory conditions.