Strong engagement of Cd137 suppresses graft-versus-host disease through dendritic cells
Sang Jun Park1,3, Hong Rae Cho1,3, Hojong Park1,3, Juyang Kim2,3, Sang Wook Kang2,3, Byungsuk Kwon2,3, Jong Soo Lee3,4, Kyung Sun Park4, Kyung Don Yoo4.
1Department of Surgery, University of Ulan College of Medicine, Ulsan, Korea; 2School of Biological Sciences, University of Ulsan, Ulsan, Korea; 3Biomedical Research Center, Ulsan University Hospital, Ulsan, Korea; 4Department of Internal Medicine , University of Ulsan College of Medicine , Ulsan , Korea
Purpose: We previously demonstrated that anti-CD137 agonist prevent acute graft-versus-host disease (GVHD) and chronic GVHD in the parent-into-unirradiated F1 acute or chronic GVHD model. Although activation-induced dell death of donor T cells is one mechanism of anti-CD137-mediated suppression of GVHD, its detailed process remains to be clarified.So we investigated the role of DC with anti-CD137 in GVHD suppression.
Methods: Induction of cGVHD Single-cell suspensions in PBS were prepared from the spleens and lymph nodes of female bm12 mice. Chronic GVHD was induced by transfer of 8 x 107 of bm12 cells into the tail vein of female wild-type and CD137-/- mice. Immediately thereafter, 200 μg of anti-CD137 mAb (3E1) or control Ig was intraperitoneally administered.MACS purification and FACS sorting of DC subsets Splenocytes were prepared by digestion. For purification of CD11b+ DCs, CD8α- DCs were first removed by a negative selection using anti-CD8α-microbeads . The remained cells were positively selected using anti-CD11c-microbeads . For purification of CD8α+ DCs, a negative selection of splenocytes with anti-CD11b-microbeads and a positive selection with anti-CD11c-microbeads were sequentially performed. For FACS sorting of DC subsets, DCs were first enriched from splenocytes using anti-CD11c-microbeads. The enriched cells were then stained with anti-CD11 and anti-CD8α+ mAb at 4 °C for 30 min. After the cells were washed twice with PBS buffer containing 1% BSA, CD8α+ and CD11b+ DCs were sorted using FACSAria III.
Results: Here, we report that in vivo engagement of CD137 in chronic GVHD mice massively induced the generation of PD-L1hiPD-L2+OX40+IL-10+CD11b+ dendritic cells (DCs) and such regulatory DCs could prevent either chronic or acute GVHD. IL-10 is required for these regulatory DCs to expand conventional Treg cells. Interestingly, a lower number of Treg cells suppressed acute GVHD compared to chronic GVHD, suggesting that autoantibody production is governed by less stringent immunoregulation. In some GVHD models, however, anti-CD137-primed DCs potently induced activation-induced cell death of donor T cells.
Conclusions: In conclusion, our study indicates that anti-CD137 antibody suppresses acute and chronic GVHD by different mechanisms involving distinct DCs subsets.
There are no comments yet...