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

• Published in: Cellular immunology Vol. 358; p. 104216
• Main Authors: Fu, Richard Y., Chen, Alex C., Lyle, Meghan J., Chen, Chun-Yu, Liu, Chao Lien, Miao, Carol H.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.12.2020
• Subjects: Adoptive cell therapy; Animals; Anti-factor VIII inhibitors; Antibodies, Monoclonal - immunology; Antibodies, Neutralizing - immunology; Antibody response; CAR-Tregs; CD4-Positive T-Lymphocytes - immunology; Chimeric antigen receptor; Factor VIII; Factor VIII - genetics; Factor VIII - immunology; Forkhead Transcription Factors - genetics; Forkhead Transcription Factors - immunology; Forkhead Transcription Factors - metabolism; Genetic Therapy - methods; HEK293 Cells; Hemophilia A; Hemophilia A - immunology; Hemophilia A - metabolism; Hemophilia A - therapy; Humans; Immune Tolerance - immunology; Immunotherapy, Adoptive - methods; Male; Mice; Mice, Inbred C57BL; Receptors, Chimeric Antigen - genetics; Receptors, Chimeric Antigen - immunology; Receptors, Chimeric Antigen - metabolism; Regulatory T cells; T-Lymphocytes, Regulatory - immunology; T-Lymphocytes, Regulatory - metabolism; T-Lymphocytes, Regulatory - transplantation; Tolerance induction; Chimeric antigen receptor; Tolerance induction; Anti-factor VIII inhibitors; Factor VIII; CAR-Tregs; Regulatory T cells; Adoptive cell therapy; Hemophilia A; Antibody response
• ISSN: 0008-8749; 1090-2163
• DOI: 10.1016/j.cellimm.2020.104216

•FVIII-specific Tregs were produced by transducing CD4+ T cells with F8CARmFoxp3-LV..•The gene-modified T cells suppressed anti-FVIII immune responses in vitro.•Adoptive FVIIICAR-Treg therapy prevented anti-FVIII antibody production in HemA mice. 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.