By keeping CD8+ T cell alloreactivity out, this CD4+ T cell-restricted model allows us to investigate the reciprocal interplay between Th1, Th17 and Treg cells in the context of transplantation. IL-2-mediated Treg expansion, intragraft recruitment or suppressive capacities. Instead, IL-17A prevented allograft rejection by inhibiting Th1 alloreactivity independently of Tregs. Indeed, T-bet expression Avarofloxacin of naive alloreactive CD4+ T cells and the subsequent Th1 immune response was significantly enhanced in IL-17A deficient mice. Our results illustrate for the first time a protective role of IL-17A in CD4+-mediated allograft rejection process. Introduction We and others recently identified a role for IL-17A producing CD4+ and CD8+ T cells Rabbit Polyclonal to FCRL5 in the allograft rejection process C. Indeed, IL-17A neutralization has been shown to prolong allograft survival in either minor mismatched Avarofloxacin skin transplants  or in T-bet deficient recipients grafted with MHC-mismatched cardiac allografts , . However, single IL-17A deficiency is no longer effective to prevent spontaneous rejection of MHC I and/or MHC II mismatched skin allografts in untouched recipients. This probably reflects the redundant pathways of allograft rejection involving numerous alloreactive effector cells belonging to T helper (Th)1, Th2 and CD8+ T cells . Moreover, in agreement with the concept of mutual regulation of Th subsets, early production of IFN- or IL-4 from differentiating Th0 cells potentially impairs development of alloreactive IL-17A producing T cells . By inhibiting Th1 and Th2 cells, Tregs may promote de novo Th17 differentiation as shown in different experimental models , . On the other hand, in vivo Treg expansion by supplying exogenous IL-2 is an efficient strategy to dampen autoimmunity and transplant rejection C. In mice, this goal was achieved by coupling IL-2 to an anti-IL-2 monoclonal antibody that targets specifically Treg cells , . By using this approach, we hypothesized that a Treg boost might promote an IL-17A-dependent mechanism of graft rejection by inhibiting the Th1 and Th2 pathways in a well-established murine model of CD4+ T cell-mediated alloreactivity. Surprisingly, our results indicated that IL-17A has the opposite effect by supporting long-term acceptance induced by the IL-2-mediated Treg expansion in vivo. We further demonstrated that IL-17A directly inhibits Th1 alloreactive cells and cooperates with IL-2-expanded Tregs for preventing graft rejection. Materials and Methods Mice C57Bl/6.C-H-2bm12 mice (bm12) were obtained from The Jackson Laboratory. Wild type C57Bl/6 (B6) mice were purchased from Harlan, Netherlands. IL-17A-/- C57Bl/6 mice were kindly provided by Dr Iwakura. Eight to twelve weeks old animals were used and animals were bred in our specific pathogen-free animal facility. All animals received humane care in compliance with the Principles of Laboratory Animal Care formulated by the National Institute of Health (Guide for the Care and Use of Laboratory Animals, Eighth Edition, National Research Council, 2010) and protocols were approved by the Ethical Committee from the Biopole ULB Charleroi, Universit Libre de Avarofloxacin Bruxelles (agreement # LA2500519). Skin grafting, treatments with antibodies and IL-2/anti-IL2 complex Mice were anaesthetized with a mixture of xylazine (Rompun) 5% and ketamine 10% in phosphate-buffered saline (PBS). A total of 100 L per 20g of body weight was injected intraperitoneally. Skin grafting was performed according to an adaptation of the method of Billingham and Medawar. Briefly, skin grafting was conducted Avarofloxacin by grafting full-thickness tail skin (1 cm2) on the lateral flank. Grafts were monitored daily after the removal of the bandage on day 8 and considered rejected when more than 75% of epithelial breakdown had occurred. IL-2/anti-IL-2 complex was formed by incubating 1 g recombinant mouse IL-2 (eBioscience) and 9 g of purified anti-mouse IL-2 (clone JES6-1A12) (Bio-X-cell) for 30 min at 37C. This complex was administered at days 0, 1 and 2 after transplantation. The neutralizing anti-IL-17A monoclonal antibody (clone MM17F3, provided by Dr Huytenhove Catherine, Universit Catholique de Louvain, Belgium) and the Isotype control antibody (clone MOPC-21, obtained from BioXcell) were intraperitoneally injected.
- KY\02327 showed zero genetic toxicity within a bacterial change mutation assay (Maron & Ames, 1983) (Appendix?Desk?S3)
- CY designed the scholarly research, contributed towards the dialogue and edited the manuscript
- That is important if you want to better understand and predict chlamydia and transmission dynamics and evolution from the virus
- By keeping CD8+ T cell alloreactivity out, this CD4+ T cell-restricted model allows us to investigate the reciprocal interplay between Th1, Th17 and Treg cells in the context of transplantation