title: FVIII-specific human chimeric antigen receptor T-regulatory cells suppress T- and B-cell responses to FVIII.
abstract: Replacement therapy with factor VIII (FVIII) is used in patients with hemophilia A for treatment of bleeding episodes or for prophylaxis. A common and serious problem with this therapy is the patient's immune response to FVIII, because of a lack of tolerance, leading to the formation of inhibitory antibodies. Development of tolerogenic therapies, other than standard immune tolerance induction (ITI), is an unmet goal. We previously generated engineered antigen-specific regulatory T cells (Tregs), created by transduction of a recombinant T-cell receptor (TCR) isolated from a hemophilia A subject's T-cell clone. The resulting engineered T cells suppressed both T- and B-cell effector responses to FVIII. In this study, we have engineered an FVIII-specific chimeric antigen receptor (ANS8 CAR) using a FVIII-specific scFv derived from a synthetic phage display library. Transduced ANS8 CAR T cells specific for the A2 domain proliferated in response to FVIII and ANS8 CAR Tregs were able to suppress the proliferation of FVIII-specific T-effector cells with specificity for a different FVIII domain in vitro. These data suggest that engineered cells are able to promote bystander suppression. Importantly, ANS8 CAR-transduced Tregs also were able to suppress the recall antibody response of murine splenocytes from FVIII knockout mice to FVIII in vitro and in vivo. In conclusion, CAR-transduced Tregs are a promising approach for future tolerogenic treatment of hemophilia A patients with inhibitors.
authors.affiliation: Department of Medicine, Uniformed Services University of Health Sciences, Bethesda, MD; and.
authors.forename: Jeongheon
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Department of Pediatrics, Molecular Hemostasis and Immunodeficiency, University Hospital Frankfurt, Goethe University, Frankfurt, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Schmidt
authors.affiliation: Department of Medicine, Uniformed Services University of Health Sciences, Bethesda, MD; and.
authors.forename: Ai-Hong
authors.initials: AH
authors.lastname: Zhang
authors.affiliation: Department of Pediatrics, Molecular Hemostasis and Immunodeficiency, University Hospital Frankfurt, Goethe University, Frankfurt, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Königs
authors.affiliation: Department of Medicine, Uniformed Services University of Health Sciences, Bethesda, MD; and.
authors.forename: Yong Chan
authors.initials: YC
authors.lastname: Kim
authors.affiliation: Department of Medicine, Uniformed Services University of Health Sciences, Bethesda, MD; and.
authors.forename: David W
authors.initials: DW
authors.lastname: Scott
mesh_terms: D000818:Animals; D001402:B-Lymphocytes; D060846:Cell Engineering / Q000379:methods*; D005169:Factor VIII / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D007165:Immunosuppression Therapy / Q000379:methods*; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014161:Transduction, Genetic
chemical_list: D011948:Receptors, Antigen, T-Cell; D005169:Factor VIII