FVIII-specific human chimeric antigen receptor T-regulatory cells suppress T- and B-cell responses to FVIII

Blood. 2017 Jan 12;129(2):238-245. doi: 10.1182/blood-2016-07-727834. Epub 2016 Nov 15.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B-Lymphocytes
  • Cell Engineering / methods*
  • Factor VIII / immunology*
  • Flow Cytometry
  • Humans
  • Immunosuppression / methods*
  • Lymphocyte Activation / immunology
  • Mice
  • Mice, Knockout
  • Receptors, Antigen, T-Cell / immunology*
  • T-Lymphocytes, Regulatory / immunology*
  • Transduction, Genetic

Substances

  • Receptors, Antigen, T-Cell
  • Factor VIII