Isolation, purification and function of mouse CD4 + CD25+ regulatory T lymphocytes in vitro

Objective To establish a method for isolation and purification of CD4+ CD25+ regulatory T lymphocytes (Treg), and to identify partial functions of these cells. Methods Lymphocytes were isolated from the mouse spleens and then CD4+ CD25+ T cells were sorted by magnetic bead cell sorting (MACS) system. The purity of CD4+ CD25+ T cells were analyzed by flow cytometry (FCM). The activity of them was detected by trypan blue staining. Interleukin (IL)-2 and IL-10 levels in culture supernatant were determined by enzyme linked immunosorbent assay (ELISA). Results The purity of CD4+ CD25+ T cells sorted by MACS was 83%-96%. There was significant difference in the levels of IL-2 and IL-10 secreted by lymphocytes among CD4+ CD25+ Treg group [ (10.25±3.31), (40.32±8.05) ng/L], CD4+ CD25- T group [(58.21±13.05),(11.52±3.01)ng/L] and mixed culture group [ (39.54±13.82), (31.25±4.36)ng/L (P<0.05,P<0.01).Conclusion High purity of CD4+ CD25+ Treg with immune regulatory function can be isolated by MACS. The immunosuppression of CD4+ CD25+ Treg to CD4+ CD25- T was related to the regulation of IL-10 through IL-2. Key words: T cells;  CD4;  CD25;  Immunosuppression