EBAG9-silencing exerts an immune checkpoint function without aggravating adverse effects


  • A. Wirges
  • M. Bunse
  • J.J. Joedicke
  • E. Blanc
  • V. Gudipati
  • M.W. Moles
  • H. Shiku
  • D. Beule
  • J.B. Huppa
  • U.E. Höpken
  • A. Rehm


  • Molecular Therapy


  • Mol Ther 30 (11): 3358-3378


  • Chimeric antigen receptor (CAR) T cells have revolutionized treatment of B-cell malignancies. However, enhancing the efficacy of engineered T cells without compromising their safety is warranted. The estrogen receptor-binding fragment-associated antigen 9 (EBAG9) inhibits release of cytolytic enzymes from cytotoxic T lymphocytes. Here, we examined the potency of EBAG9-silencing for the improvement of adoptive T cell therapy. Micro-RNA-mediated EBAG9 downregulation in transplanted CTLs from immunized mice improved their cytolytic competence in a tumor model. In tolerant female recipient mice that received organ transplants, a minor histocompatibility antigen was turned into a rejection antigen by Ebag9 deletion, indicating an immune checkpoint function for EBAG9. Considerably less EBAG9-silenced human CAR T cells were needed for tumor growth control in a xenotransplantation model. Transcriptome profiling did not reveal additional risks regarding genotoxicity or aberrant differentiation. A single-step retrovirus transduction process links CAR or TCR expression with miRNA-mediated EBAG9 downregulation. Despite higher cytolytic efficacy, release of cytokines associated with cytokine release syndrome remains unaffected. Collectively, EBAG9-silencing enhances effector capacity of TCR- and CAR-engineered T cells, results in improved tumor eradication, facilitates efficient manufacturing, and decreases the therapeutic dose.