The Allogeneic but not Syngeneic Dendritic Cells Effectively Generated Regulatory T Cells from Total Cd4⁺ Population without Exogenous Cytokines

Dendritic cells (DC) play a critical role in both the expansion of natural regulatory T cells (nTreg) and conversion of induced Treg (iTreg) from their precursors. In the present study, we evaluated the potential of DC to generate Treg from total CD4⁺ population which contains both nTreg and the precursors, and found that allogeneic (allo‐DC) but not syngeneic DC (syn‐DC) could effectively generated Foxp3⁺ Treg from total CD4⁺ population in the absence of exogenous cytokines. Compared with freshly purified CD4⁺ T cells, allo‐DC‐stimulated CD4⁺ T cells showed increased percentage of CD4⁺CD25⁺Foxp3⁺ Treg by 5–7‐folds while syn‐DC‐stimulated CD4⁺ T cells did not. Furthermore, we demonstrated that the significant amounts of endogenous IL‐2 and TGF‐β, at least partially, contributed to the expansion of nTreg and conversion of iTreg in this cocultural system, respectively. Importantly, similar to nTreg, these allo‐DC‐generated Treg were capable of suppressing T cell response in vitro. Thus, our research provides a novel and efficient strategy for generation of Treg from total CD4⁺ population.