IL-21–producing effector Tfh cells promote B cell alloimmunity in lymph nodes and kidney allografts
Hengcheng Zhang, Cecilia B. Cavazzoni, Manuel A. Podestà, Elsa D. Bechu, Garyfallia Ralli, Pragya Chandrakar, Jeong-Mi Lee, Ismail Sayin, Stefan G. Tullius, Reza Abdi, Anita S. Chong, Bruce R. Blazar, Peter T. Sage
Hengcheng Zhang, Cecilia B. Cavazzoni, Manuel A. Podestà, Elsa D. Bechu, Garyfallia Ralli, Pragya Chandrakar, Jeong-Mi Lee, Ismail Sayin, Stefan G. Tullius, Reza Abdi, Anita S. Chong, Bruce R. Blazar, Peter T. Sage
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Research Article Immunology Transplantation

IL-21–producing effector Tfh cells promote B cell alloimmunity in lymph nodes and kidney allografts

Abstract

Follicular helper T (Tfh) cells have been implicated in controlling rejection after allogeneic kidney transplantation, but the precise subsets, origins, and functions of Tfh cells in this process have not been fully characterized. Here we show that a subset of effector Tfh cells marked by previous IL-21 production is potently induced during allogeneic kidney transplantation and is inhibited by immunosuppressive agents. Single-cell RNA-Seq revealed that these lymph node (LN) effector Tfh cells have transcriptional and clonal overlap with IL-21–producing kidney-infiltrating Tfh cells, implicating common origins and developmental trajectories. To investigate the precise functions of IL-21–producing effector Tfh cells in LNs and allografts, we used a mouse model to selectively eliminate these cells and assessed allogeneic B cell clonal dynamics using a single B cell culture system. We found that IL-21–producing effector Tfh cells were essential for transplant rejection by regulating donor-specific germinal center B cell clonal dynamics both systemically in the draining LN and locally within kidney grafts. Thus, IL-21–producing effector Tfh cells have multifaceted roles in Ab-mediated rejection after kidney transplantation by promoting B cell alloimmunity.

Authors

Hengcheng Zhang, Cecilia B. Cavazzoni, Manuel A. Podestà, Elsa D. Bechu, Garyfallia Ralli, Pragya Chandrakar, Jeong-Mi Lee, Ismail Sayin, Stefan G. Tullius, Reza Abdi, Anita S. Chong, Bruce R. Blazar, Peter T. Sage

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Figure 5

IL-21–producing Tfh cells are required for Ab-mediated rejection after kidney transplantation.

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IL-21–producing Tfh cells are required for Ab-mediated rejection after k...
(A) Schematic of IL-21–producing Tfh cell deletion using F/Ex-DTR mice. Control (Il21CreRosa26Lox-STOP-Lox-YFPCxcr5WT) or F/Ex-DTR (Il21CreRosa26Lox-STOP-Lox-YFPCxcr5Lox-STOP-Lox-DTR) mice were transplanted with a Balb/c kidney and cells deleted with the administration of DT. Life-sustaining, in B–D,or non–life-sustaining, in E–K, transplants were performed. (B) Survival of transplanted recipients between the control and the F/Ex-DTR group. MST, median survival time. (C) Serum creatinine levels of recipient mice. (D) Representative histological images of transplanted kidneys at the time of graft rejection. Scale bars: 100 μm; original magnification: ×100. (E) Gating strategy for IL-21–producing Tfh cells (gated as CD4+CD19–CXCR5+ICOS+GITR–YFP+) in the dLNs. (F) Quantification of CXCR5+ cells in total CD4+ T cells, IL-21–producing Tfh (Tfh21) and cell number, IL-21–nonproducing (IL-21–) Tfh cells, and Tfr (CD4+CD19–CXCR5+ICOS+GITR+) cells in dLNs. (G) Quantification of infiltrating lymphocytes, CD4+ T cells, and CD19+ B cells, as well as the frequency of CD4+ T cells, in transplanted grafts. (H) Quantification of IL-21–producing CD4+ T cells in kidney grafts at day 20 or 40 after transplantation. Left: frequency; and right: cell number. (I) Total IgG DSAs from serum of mice 40 days after transplantation. (J) Single antigen assays to assess IgG allospecificity. Syn, syngeneic. (K) Representative histological images of transplanted kidneys at postoperative day 40, including H&E, IHC staining for CD3 and B220, and IF staining for C4d. Scale bars: 100 μm; original magnification: ×100. Data are combined from 2 independent experiments with n = 3–5 mice per group. Kaplan-Meier survival analysis and a log-rank test for survival analysis for B and Student’s 2-tailed unpaired t test for 2-group comparisons for C and F–J. *P < 0.05; **P < 0.01.