CD4+ T cells engineered with FVIII-CAR and murine Foxp3 suppress anti-factor VIII immune responses in hemophilia a mice

Richard Y. Fu, Alex C. Chen, Meghan J. Lyle, Chun Yu Chen, Chao Lien Liu, Carol H. Miao

Research output: Contribution to journalArticle

Abstract

Although protein replacement therapy provides effective treatment for hemophilia A patients, about a third of severe patients develop neutralizing inhibitor antibodies to factor VIII. Adoptive transfer of regulatory T cells (Tregs) has shown promise in treating unwanted immune responses. In previous studies, transferred polyclonal Tregs ameliorated the anti-factor VIII immune responses in hemophilia A mice. In addition, factor VIII-primed Tregs demonstrated increased suppressive function. However, antigen-specific Tregs are a small fraction of the total lymphocyte population. To generate large numbers of factor VIII-specific Tregs, the more abundant murine primary CD4+ T cells were lentivirally transduced ex vivo to express Foxp3 and a chimeric antigen receptor specific to factor VIII (F8CAR). Transduced cells significantly inhibited the proliferation of factor VIII-specific effector T cells in suppression assays. To monitor the suppressive function of the transduced chimeric antigen receptor expressing T cells in vivo, engineered CD4+CD25+Foxp3+F8CAR-Tregs were sorted and adoptively transferred into hemophilia A mice that are treated with hydrodynamically injected factor VIII plasmid. Mice receiving engineered F8CAR-Tregs showed maintenance of factor VIII clotting activity and did not develop anti-factor VIII inhibitors, while control CD4+T cell or PBS recipient mice developed inhibitors and had a sharp decrease in factor VIII activity. These results show that CD4+ cells lentivirally transduced to express Foxp3 and F8CAR can promote factor VIII tolerance in a murine model. With further development and testing, this approach could potentially be applied to human hemophilia patients.

Original languageEnglish
Article number104216
JournalCellular Immunology
Volume358
DOIs
Publication statusPublished - Dec 2020
Externally publishedYes

Keywords

  • Adoptive cell therapy
  • Anti-factor VIII inhibitors
  • Antibody response
  • CAR-Tregs
  • Chimeric antigen receptor
  • Factor VIII
  • Hemophilia A
  • Regulatory T cells
  • Tolerance induction

ASJC Scopus subject areas

  • Immunology

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