[Progress of study on ex vivo expansion of CD4(+) CD25(+) T regulatory cells]

There has been a history of 30 years in the study of CD4(+)CD25(+) T regulatory cells (Treg) which primarily play a role of immune suppression in vivo. Many autoimmune diseases are related to the decrease and the disorder of these cells, such as multiple sclerosis, non-obese diabet (NOD) and lupus erythematosus. In the field of transplantation tolerance, the role played by Treg is also very important. All of these features have drawn the attention to the prevention of autoimmune diseases and the rejection of transplantation. However, the low frequency of Treg in vivo affected their use and study. Currently, many techniques about expansion of Treg in vitro have been established so as to overcome the problem of their limited cell numbers in vivo. Recent studies suggest that antigen-specific T regulator cells (sTreg) expanded by dentritic cells (DC) showed a superior immunosuppression in comparison with polyclonal Treg expanded by anti-CD3/CD28Ab, which is the focus of current studies. This article mainly reviews and compares the expansion techniques and the mechanism of regulatory T cells.