Regulatory effect of tumor necrosis factor-α induced protein 8 like-2 expression on immunosuppressive activity of CD4 + CD25 + regulatory T cells in mice

Abstract

Objective To observe the expression of tumor necrosis factor-α induced protein 8 like-2 (TIPE2) in CD4 + CD25 + regulatory T cells ( CD4 + CD25 + Tregs) and analyze its potential effect on immunosuppressive activity of CD4 + CD25 + Tregs. Methods CD4 + CD25 + Tregs were purified from spleen of the BALB/c mice by using magnetic cell sorting system.The expressions of TIPE2 mRNA and protein in CD4 + CD25 + Tregs were detected by using RT-PCR and Western blot.CD4 + CD25 +Tregs were further infected with the recombinant lentiviruses that carried small interference RNA(siRNA)to knock down the TIPE2 expression.Based on the expressions of cell surface molecules including cytotoxic T-lymphocyte-associated antigen (CTLA)-4 and forkhead/winged helix transcription factor p3 (Foxp3) detected by flow cytometry and the levels of cytokines including interleukin (IL)-10 and transforming growth factor (TGF)-3 examined by ELISA in CD4 + CD25 + Tregs,the functional role of TIPE2 in controlling suppressive activity of CD4 + CD25 + Tregs was analyzed.In the meantime,the proliferation activities of T effector cells were assayed by MTT test. Results A 147 bp TTPE2 gene band and a clear TIPE2 band with a molecular mass of approximately 21 000 in CD4 + CD25 + Tregs were detected by using Westem blot.Cell surface molecule as well as cytokine expressions were significantly down-regulated when the CD4 + CD25 + Treg stimulated and activated by anti-CD3/CD28 was cultured for 24 hours after the siRNA silenced CD4 + CD25 + Treg cells ( P ＜ 0.01 ).Meanwhile,the suppression role of CD4 +CD25 + Tregs on the proliferation activity of T effector cells was weakened obviously ( P ＜ 0.05 ). Conclusions As an important immunoregulatory molecule,TIPE2 not only expresses in the CD4 + CD25 +Tregs,but also affects the immunosuppressive function of CD4 + CD25 + Tregs. Key words: Immunity, cellular; Tumor necrosis factor alpha; Mice; Protein 8 like-2