CD40-activated B cells are more potent than immature dendritic cells to induce and expand CD41 regulatory T cells

CD4^(+)regulatory T cells(Tregs)play an important role in maintaining immune tolerance by suppressing pathologic immune responses.,The generation of large numbers of antigen-specific Tregs ex vivo is critical for the development of clinical immunotherapy based on the adoptive transfer of Tregs.Both CD40-activated B cells(CD40-B)and immature dendritic cells(imDCs)have been used as professional antigen-presenting cells(APCs)to generate antigen-specific Tregs.However,the efficiencies of CD40-B and imDCs to generate CD4^(+)Tregs have not been compared directly and the mechanism driving the generation of these Tregs remains largely unknown.In this study,we found that CD40-B exhibited mature phenotypes and were more able to induce and expand CD4^(high)"CD25^(+)Tregs than imDCs.Moreover,Tregs induced by CD40-B had greater suppressive capacity than those induced by imDCs.The generation of CD4^(high)CD25^(+)Tregs by CD40-B and imDCs is cell-cell contact dependent and partially relies on the expression of human leukocyte antigen(HLA)-DR and CD80/86.Differences in CD4^(high)CD25^(+)Treg generation efficiency were largely explained by the production of endogenous IL-2 by CD40-B.Our results suggest that CD40-B is better able to generate large numbers of antigen-specific Tregs than imDCs.Additionally,using CD40-B to generate Tregs may accelerate the clinical use of Treg-based immunotherapy in the treatment of allograft rejection,graft versus host disease(GVHD)and autoimmune diseases.

Tolerogenic dendritic cells and their applications in transplantation

In transplantation immunology, the ultimate goal is always to successfully and specifically induce immune tolerance of allografts. Tolerogenic dendritic cells （toI-DCs） with immunoregulatory functions have attracted much attention as they play important roles in inducing and maintaining immune tolerance. Here, we focused on tol-DCs that have the potential to promote immune tolerance after solid-organ transplantation. We focus on their development and interactions with other regulatory cells, and we also explore various toI-DC engineering protocols. Harnessing tol-DCs represents a promising cellular therapy for promoting long-term graft functional survival in transplant recipients that will most likely be achieved in the future.