Cyclic Helix B Peptide Prolongs Skin Allograft Survival via Inhibition of B Cell Immune Responses in a Murine Model

• Main Authors: Long Zheng, Xuanchuan Wang, Linkun Hu, Wenjun Gao, Weitao Zhang, Xuepeng Zhang, Chao Hu, Ruiming Rong, Cheng Yang, Dong Zhu
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2021-05-01
• Series: Frontiers in Immunology
• Subjects: cyclic helix B peptide; antibody-mediated rejection; plasma cells; germinal center B cells; Tfh cells; donor specific antibodies
• Online Access: https://www.frontiersin.org/articles/10.3389/fimmu.2021.682749/full

Antibody-mediated rejection (AMR) represents a major cause of allograft dysfunction and results in allograft failure in solid organ transplantation. Cyclic helix B peptide (CHBP) is a novel erythropoietin-derived peptide that ameliorated renal allograft rejection in a renal transplantation model. However, its effect on AMR remains unknown. This study aimed to investigate the effect of CHBP on AMR using a secondary allogeneic skin transplantation model, which was created by transplanting skin from BALB/c mice to C57BL/6 mice with or without CHBP treatment. A secondary syngeneic skin transplantation model, involving transplantation from C57BL/6 mice to C57BL/6 mice, was also created to act as a control. Skin graft rejection, CD19+ B cell infiltration in the skin allograft, the percentages of splenic plasma cells, germinal center (GC) B cells, and Tfh cells, the serum levels of donor specific antibodies (DSAs), and NF-κB signaling in splenocytes were analyzed. Skin allograft survival was significantly prolonged in the CHBP group compared to the allogeneic group. CHBP treatment also significantly reduced the CD19+ B cell infiltration in the skin allograft, decreased the percentages of splenic plasma cells, GC B cells, and Tfh cells, and ameliorated the increase in the serum DSA level. At a molecular level, CHBP downregulated P100, RelB, and P52 in splenocytes. CHBP prolonged skin allograft survival by inhibiting AMR, which may be mediated by inhibition of NF-κB signaling to suppress B cell immune responses, thereby decreasing the DSA level.