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 6

Therapeutic adoptive therapy of CD19-targeted CAR Tregs efficiently suppresses B cells and antibody production in vivo.

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Therapeutic adoptive therapy of CD19-targeted CAR Tregs efficiently supp...
Severely immunodeficient (NOD.Cg-PrkdcscidIl2rgtm1Wjl/Sz [NSG]) mice were i.v. injected with 5 × 106 human PBMCs. Autologous CD19-CAR Tregs and polyclonal Tregs (2 × 106) were adoptively transferred 7 days after PBMC injection. (A) Total IgG antibody and IgM antibody levels in serum on days 14, 21, and 28 (n = 4–7). (B and C) Number of B cells (FVD–hCD45+hCD20+) (B) and injected Tregs (FVD–hCD45+hCD4+Venus+) (C) in the peripheral blood on days 14, 21, and 28 measured by flow cytometric analysis (n = 4–7). P values was determined using (C) 2-tailed Student’s t test or (A, B, and D) 1-way ANOVA (*P < 0.05, **P < 0.01, NS, comparing red or blue symbols with each black symbol; #P < 0.05 and ##P < 0.01, comparing black symbols with each open symbol). Data are presented as the mean ± SEM. (D) GvHD score was measured on day 28 (n = 5). (E) NSG mice were i.v. injected with 5 × 106 human PBMCs. Autologous CD19-CAR Tregs and CD19-CAR CD8+ T cells (2 × 106) were adoptively transferred 7 days after PBMC injection. GvHD score and body weight were measured from day 0 to day 50 (n = 5). (E) P values were determined using 2-way ANOVA (*P < 0.05, **P < 0.01; NS, compared with black circle). Data are presented as mean ± SEM.