Clinical-Grade–Expanded Regulatory T Cells Prevent Graft-versus-Host Disease While Allowing a Powerful T Cell–Dependent Graft-versus-Leukemia Effect in Murine Models

作者：Beatrice Del Papa, Loredana Ruggeri, Elena Urbani, Stefano Baldoni, Debora Cecchini, Tiziana Zei, Roberta Iacucci Ostini, Barbara Crescenzi, Alessandra Carotti, Antonio Pierini, Paolo Sportoletti, Paolo Di Bartolomeo, Franca Falzetti, Cristina Mecucci, Andrea Velardi, Massimo F. Martelli, Mauro Di Ianni · 发表于：Transplantation and Cellular Therapy · 年份：2017 · DOI：10.1016/j.bbmt.2017.07.009 · 被引用次数：31 · 研究领域：CAR-T cell therapy research、Immune Cell Function and Interaction、T-cell and B-cell Immunology

We developed a good manufacturing practices-compatible expansion protocol to improve number and purity of regulatory T cells (Tregs) available for clinical trials. Six clinical-grade separation procedures were performed, followed by expansion with high-dose interleukin (IL)-2, anti-CD3/anti-CD28 TCR stimulation, and rapamycin for 19 days achieving a median of 8.5-fold (range, 6.25 to 13.7) expansion. FOXP3 expression was stably maintained over the culture period, while the percentage of CD127 was significantly reduced. The in vitro suppression assay showed a strong Mixed Lymphocytes Reaction inhibition. In vitro amplification did not induce any karyotypic modification. To evaluate the graft-versus-host disease (GVHD)/graft-versus-leukemia (GVL) bifunctional axis, expanded Tregs and conventional T cells (Tcons) were tested in NOD/SCID/IL2Rgnull mice injected with primary acute myeloid leukemia (AML) cells, AML cell line, acute lymphoid leukemia Philadelphia cell line, or Burkitt-like lymphoma cell line. All mice that received leukemia cells together with expanded Tregs and Tcons were rescued from leukemia and survived without GVHD, showing that Treg expansion procedure did not compromise GVHD control and the strong Tcon-mediated GVL activity. This report might represent the basis for treating high-risk leukemia and/or relapsed/refractory leukemia patients with high-dose Treg/Tcons.