CD28/CTLA-4/B7 and CD40/CD40L costimulation and activation of regulatory T cells  

作　　者：Isabel T Vogel Stefaan W Van Gool Jan L Ceuppens 

机构地区：[1]Laboratory of Clinical Immunology, Department of Microbiology and Immunology, KU Leuven, University Hospital Gasthuisberg [2]Laboratory of Pediatric Immunology, KU Leuven, University Hospital Gasthuisberg

出　　处：《World Journal of Immunology》2014年第2期63-77,共15页世界免疫学杂志

摘　　要：Costimulatory signals are crucial for T cell activation. Attempts to block costimulatory pathways have been effective in preventing unwanted immune reactions. In particular, blocking the CD28/cytotoxic T lymphocyte antigen(CTLA)-4/B7 interaction(using CTLA-4Ig) and the CD40/CD40 L interaction(using anti-CD40 L antibodies) prevents T cell mediated autoimmune diseases, transplant rejection and graft vs host disease in experimental models. Moreover, CTLA-4Ig is in clinical use to treat rheumatoid arthritis(abatacept) and to prevent rejection of renal transplants(belatacept). Under certain experimental conditions, this treatment can even result in tolerance. Surprisingly, the underlying mechanisms of immune modulation are still not completely understood. We here discuss the evidence that costimulation blockade differentially affects effector T cells(Teff) and regulatory T cells(Treg). The latter are required to control inappropriate and unwanted immune responses, and their activity often contributes to tolerance induction and maintenance. Unfortunately, our knowledge on the costimulatory requirements of Treg cells is very limited. We therefore summarize the current understanding ofthe costimulatory requirements of Treg cells, and elaborate on the effect of anti-CD40 L antibody and CTLA-4Ig treatment on Treg cell activity. In this context, we point out that the outcome of a treatment aiming at blocking the CD28/CTLA-4/B7 costimulatory interaction can vary with dosing, timing and underlying immunopathology.Costimulatory signals are crucial for T cell activation. Attempts to block costimulatory pathways have been effective in preventing unwanted immune reactions. In particular, blocking the CD28/cytotoxic T lymphocyte antigen （CTLA）-4/B7 interaction （using CTLA-4Ig） and the CD40/CD40L interaction （using anti-CD40L antibod-ies） prevents T cell mediated autoimmune diseases, transplant rejection and graft vs host disease in experi-mental models. Moreover, CTLA-4Ig is in clinical use to treat rheumatoid arthritis （abatacept） and to prevent rejection of renal transplants （belatacept）. Under certain experimental conditions, this treatment can even result in tolerance. Surprisingly, the underlying mechanisms of immune modulation are still not completely understood. We here discuss the evidence that costimulation block-ade differentially affects effector T cells （Teff） and regu-latory T cells （Treg）. The latter are required to control inappropriate and unwanted immune responses, and their activity often contributes to tolerance induction and maintenance. Unfortunately, our knowledge on the costimulatory requirements of Treg cells is very limited. We therefore summarize the current understanding of the costimulatory requirements of Treg cells, and elabo-rate on the effect of anti-CD40L antibody and CTLA-4Ig treatment on Treg cell activity. In this context, we point out that the outcome of a treatment aiming at blocking the CD28/CTLA-4/B7 costimulatory interaction can vary with dosing, timing and underlying immunopathology.

关 键 词：Regulatory T cells Tolerance CYTOTOXIC T lymphocyte antigen-4Ig Anti-CD40L COSTIMULATION 

分 类 号：R1[医药卫生—公共卫生与预防医学]