Day/night changes of thymus-deriving natural regulatory T cell development and function

Abstract Activity of the immune system shows day/night rhythmicity. Changes in the migration and biological activities of immune cells are strongly regulated by the HPA axis. Another mechanism governing the level of the immune response is based on the suppressive activity of natural regulatory T cells CD4+CD25+Foxp3 + (nTregs) which play a crucial role in the maintenance of self-tolerance and immune homeostasis. The aim of our study was to answer the question: are nTregs changing their development and suppressive activity according to day/night cycle? We demonstrated the effect of day time on nTreg distribution in the thymus and their suppressive potential to inhibit the proliferation of activated responder T cells.