To explore the effects of microRNA-150 deletion on the development and homeostasis of regulatory T cells (Treg),γδT cells,NK and NKT cells.Methods:microRNA-150 knockout mice were used and microRNA-150 expression was detected by Real-time PCR.The numbers of Treg ,γδT,NK and NKT cells in the thymus and spleen of normal control and microRNA-150 knockout mice were detected by Flow cytometry.Cell apoptosis was detected by Annexin V staining , and cell proliferation was detected by 5-Bromo-2-deoxyUridine ( Brdu ) incorporation.Results: microRNA-150 deletion did not affect the development and homeostasis of regulatory T cells (Treg) andγδT cells.However,microRNA-150 deletion resulted in a significant reduction of the NK and thymic NKT cell number.In addition, microRNA-150 deleted NK and NKT cells showed an arrested developmental and maturational phenotype with a reduced expression of NK 1.1 and CD122.Moreover , cell apoptosis was significantly increased in microRNA-150 deleted NK and thymic NKT cells ,while a lower cell proliferation rate was shown in the microRNA-150 deleted NK but not NKT cells.Conclusion: CD122 may play an important role in the development and homeostasis of mouse NK and NKT cells regulated by microRNA-150.