CAR19 Tregs treat murine chronic graft-versus-host disease through immune suppression without measurable B cell cytolysis
Sujeong Jin, Michael C. Zaiken, Cameron McDonald-Hyman, Christina R. Hartigan, Sara Bolivar-Wagers, Jemma H. Larson, Yiyun Peng, Sophia Hani, Megan Riddle, Asim Saha, Angela Panoskaltsis-Mortari, Eun Ko, Yujie Zhao, Rocio Amaro Marquez, Pooja Shree Marri Baskar, Cindy R. Eide, William J. Murphy, Keli L. Hippen, Geoffrey R. Hill, Jakub Tolar, Peter T. Sage, Christopher A. Pennell, Leslie S. Kean, Bruce R. Blazar
Sujeong Jin, Michael C. Zaiken, Cameron McDonald-Hyman, Christina R. Hartigan, Sara Bolivar-Wagers, Jemma H. Larson, Yiyun Peng, Sophia Hani, Megan Riddle, Asim Saha, Angela Panoskaltsis-Mortari, Eun Ko, Yujie Zhao, Rocio Amaro Marquez, Pooja Shree Marri Baskar, Cindy R. Eide, William J. Murphy, Keli L. Hippen, Geoffrey R. Hill, Jakub Tolar, Peter T. Sage, Christopher A. Pennell, Leslie S. Kean, Bruce R. Blazar
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Research Article Immunology Inflammation

CAR19 Tregs treat murine chronic graft-versus-host disease through immune suppression without measurable B cell cytolysis

Abstract

Chronic graft-versus-host disease (cGVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic transplantation. cGVHD pathophysiology involves cooperation between T follicular helper cells (TFHs) and germinal center B cells (GCBs), allo- and autoantibody depositions in cGVHD tissues, and fibrosis. We evaluated human CD19–directed chimeric antigen receptor (CAR19) T cell therapy in a clinically relevant murine cGVHD model with bronchiolitis obliterans syndrome (BOS). Although CD8+ CAR19 T cells effectively reduced peripheral B cell and GCB frequencies, pulmonary function was unimproved. In contrast, a single infusion of CAR19 CD4+ regulatory T cells (Tregs) mitigated ongoing pulmonary disease and modulated germinal centers (GCs) associated with reduced TFH frequencies compared with control Tregs but without measurable B cell depletion. Compared with EGFR Treg infusion, mice receiving CAR19 Tregs exhibited enhanced suppression of B cell activation and preserved splenic architecture, and CAR19 Treg infusion provided greater opportunities for interaction with CD19+ B cells at the B cell follicle boundary zones. Taken together with the absence of detectable B cell cytolysis, these findings were most consistent with GC suppression rather than B cell depletion as the dominant mechanism. Overall, our findings suggest that CAR19 Tregs represent a promising and safe cGVHD/BOS therapeutic strategy, offering immunosuppressive benefits and improved disease outcomes that may be more limited with CD8+ CAR19 T cell treatment.

Authors

Sujeong Jin, Michael C. Zaiken, Cameron McDonald-Hyman, Christina R. Hartigan, Sara Bolivar-Wagers, Jemma H. Larson, Yiyun Peng, Sophia Hani, Megan Riddle, Asim Saha, Angela Panoskaltsis-Mortari, Eun Ko, Yujie Zhao, Rocio Amaro Marquez, Pooja Shree Marri Baskar, Cindy R. Eide, William J. Murphy, Keli L. Hippen, Geoffrey R. Hill, Jakub Tolar, Peter T. Sage, Christopher A. Pennell, Leslie S. Kean, Bruce R. Blazar

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Figure 2

CAR19 Tregs inhibit GC reactions in murine cGVHD/BOS.

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CAR19 Tregs inhibit GC reactions in murine cGVHD/BOS. (A–E) Day 50 splee...
(A–E) Day 50 spleens from cGVHD mice treated with EGFR or CAR19 Tregs were analyzed for frequency of TFHs (FoxP3–CXCR5+PD-1+BCL6+) of CD4+ (A), frequency of TFRs (FoxP3+CXCR5+PD-1+BCL6+) of CD4+ (B), TFH/TFR ratio (C), frequency of FoxP3(GFP)+ infused Tregs of TFRs (D), and frequency of GCBs of mouse CD19 positive (mCD19+) (E). (F and G) Frequency and counts of hCD19+ B cells of lymphocytes in day 50 spleen (F) and lung (G). (H) Representative images (original magnification, ×200) of spleen sections stained for GCs with peanut agglutinin (PNA; red), CD4 (green), and DAPI (blue). Scale bars: 200 μm. (I and J) Quantification of GC sizes (I) and frequencies per mm2 (J). (K and L) Day 50 spleens were analyzed for frequencies of mature B220–mCD19– plasma cells (PCs) of total CD138+BLIMP1+ PCs (K) or immature B220+mCD19+ PCs of total PCs (L). Data are pooled from 2–4 independent experiments. (A–C, E, and F) Day 50 spleens were analyzed from BM-only (n = 26), cGVHD (n = 25), EGFR CD4+ Treg–treated (n = 21), and CAR19 CD4+ Treg–treated (n = 23) mice. (D) Day 50 spleens were analyzed from EGFR CD4+ Treg–treated (n = 17) and CAR19 CD4+ Treg–treated (n = 25) mice. (G) Day 50 lungs were analyzed from BM-only (n = 17), cGVHD (n = 16), EGFR CD4+ Treg–treated (n = 14), and CAR19 CD4+ Treg–treated (n = 10) mice. (I and J) Day 50 spleens were analyzed from BM-only (n = 13), cGVHD (n = 8), EGFR CD4+ Treg–treated (n = 11), and CAR19 CD4+ Treg–treated (n = 10) mice. (K and L) Day 50 spleens were analyzed from BM-only (n = 10), cGVHD (n = 15), EGFR CD4+ Treg–treated (n = 13), and CAR19 CD4+ Treg–treated (n = 15) mice. Statistics shown are results of 1-way ANOVA with Tukey’s correction for multiple comparisons. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.