CD19-targeted CAR regulatory T cells suppress B cell pathology without GvHD
Yuki Imura, Makoto Ando, Taisuke Kondo, Minako Ito, Akihiko Yoshimura
Yuki Imura, Makoto Ando, Taisuke Kondo, Minako Ito, Akihiko Yoshimura
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Research Article Therapeutics

CD19-targeted CAR regulatory T cells suppress B cell pathology without GvHD

Abstract

Regulatory T cells (Tregs) play essential roles in maintaining immunological self-tolerance and preventing autoimmunity. The adoptive transfer of antigen-specific Tregs has been expected to be a potent therapeutic method for autoimmune diseases, severe allergy, and rejection in organ transplantation. However, effective Treg therapy has not yet been established because of the difficulty in preparing a limited number of antigen-specific Tregs. Chimeric antigen receptor (CAR) T cells have been shown to be a powerful therapeutic method for treating B cell lymphomas, but application of CAR to Treg-mediated therapy has not yet been established. Here, we generated CD19-targeted CAR (CD19-CAR) Tregs from human PBMCs (hPBMCs) and optimized the fraction of the Treg source as CD4+CD25+CD127loCD45RA+CD45RO–. CD19-CAR Tregs could be expanded in vitro while maintaining Treg properties, including high expression of the latent form of TGF-β. CD19-CAR Tregs suppressed IgG antibody production and differentiation of B cells via a TGF-β–dependent mechanism. Unlike conventional CD19-CAR CD8+ T cells, CD19-CAR Tregs suppressed antibody production in immunodeficient mice that were reconstituted with hPBMCs, reducing the risk of graft-versus-host disease. Therefore, the adoptive transfer of CD19-CAR Tregs may provide a novel therapeutic method for treating autoantibody-mediated autoimmune diseases.

Authors

Yuki Imura, Makoto Ando, Taisuke Kondo, Minako Ito, Akihiko Yoshimura

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Figure 5

TGF-β from CAR-Tregs play a major role in the suppression of B cell proliferation and IgG production.

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TGF-β from CAR-Tregs play a major role in the suppression of B cell prol...
Primary human B cells were stimulated with anti-IgM and anti-CD40 antibodies in the presence of IL-21. (A) Total IgG antibody levels produced by primary human B cells 7 days after coculture with CD19-CAR Tregs in the presence of various neutralizing antibodies (10 μg/mL) (n = 4–5). (B) Flow cytometric analysis of CellTrace Violet dilution of CellTrace Violet–labeled primary human B cells after coculture with CD19-CAR Tregs in the presence of TGF-β type 1 receptor inhibitor RepSox (0.1 and 1 μM). The fraction of CellTrace Violetlo B cells in the absence of drug and CD19-CAR Tregs is shown as 100% in the right panel (n = 3). NC, negative control; PC, positive control; Cont IgG control IgG. (C) Total IgG antibody levels produced by primary human B cells 7 days after coculture with CD19-CAR Tregs in the presence of RepSox (1 μM) (n = 3). (A) Data are representative of independent experiments using samples from 2 healthy donors. (B and C) Data were collected using human samples provided by 1 healthy donor. (A–C) P values were determined using 1-way ANOVA (*P < 0.05, **P < 0.01 compared with the indicated 2 columns; NS, ##P < 0.01 compared with each black circle). Data are presented as mean ± SEM.