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 1

Day 28 CD8+ CAR19 T cells do not treat murine cGVHD/BOS, while CAR19 Tregs reduce disease.

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Day 28 CD8+ CAR19 T cells do not treat murine cGVHD/BOS, while CAR19 Tre...
(A) B10.BR mice were conditioned with 120 mg/kg i.p. cyclophosphamide (day –3 and day –2) followed by 6.2 Gy total-body irradiation (day –1). On day 0, recipients received 107 T cell–depleted (TCD) bone marrow (BM) from hCD19tg F1 donors plus 71.5 × 104 purified splenic T cells from C57BL/6 (B6)-Ly5 donors. Groups of cGVHD mice were infused with 0.5 × 106 expanded CD8+ CAR19- or EGFR-control effectors on day 28, and on day 50 posttransplant mice were sacrificed for terminal analysis of cGVHD/BOS disease severity. (B–D) Pulmonary function test data from BM-only (n = 14), cGVHD (n = 9), EGFR CD8+ T cell–treated (n = 5), and CAR19 CD8+ T cell–treated (n = 11) mice including resistance (B), compliance (C), and elastance (D). (E and F) Quantification of collagen deposition (percentage area trichrome) from Masson’s trichrome–stained lung sections from CD8+ CAR19 T cell treatment studies (E) with representative images from BM-only (n = 5), cGVHD (n = 4), EGFR CD8+ T cell–treated (n = 4), and CAR19 CD8+ T cell–treated (n = 5) mice (F). (G–I) Pulmonary function test data from BM-only (n = 21), cGVHD (n = 17), EGFR CD4+ Treg–treated (n = 13), and CAR19 CD4+ Treg–treated (n = 17) mice including resistance (G), compliance (H), and elastance (I). (J and K) Quantification of collagen deposition (percentage area trichrome) from Masson’s trichrome–stained lung sections from CD4+ Treg treatment studies (J) with representative images from BM-only (n = 17), cGVHD (n = 11), EGFR CD4+ Treg–treated (n = 11), and CAR19 CD4+ Treg–treated (n = 14) mice (K).(F and K) Original magnification, ×200. (B–F) Data are pooled from 2 independent experiments. (G–K) Data are pooled from 4 independent experiments. 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.