LAUSR

HighlightsTGF‐&bgr; involvement in the induction of tTregs in vitro is shown.The important role of IL‐7 in thymic Treg generation is indicated.IL‐7 and TGF‐&bgr; create conditions for efficient tTreg in vitro generation.Generated in vitro tTregs maintain their suppressive function.Cell‐to‐cell suppression is indicated rather than acting via TGF‐&bgr; or IL‐10. Abstract Thymus‐derived regulatory T cells of CD4+CD25+Foxp3+ phenotype develop as a functional, mature population playing an essential role in self‐tolerance and immune homeostasis, and exhibiting therapeutic potential to inhibit adverse immune response. Despite intensive research on thymus‐derived Tregs, the knowledge about agents involved in their generation, survival, proliferation, and biological functions is still insufficient. In this research we have focused on the role of selected cytokines in previously developed in vitro model based on the application of anti‐CD3 monoclonal antibodies. We have demonstrated an essential role of IL‐7 and TGF‐&bgr; in the generation of thymus‐derived Tregs in the co‐culture of thymocytes and JAWS II cells. In addition, in vitro generated Tregs exhibited their suppressive function similarly to Tregs sorted from freshly isolated thymus.