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.
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.
['Del Papa|Beatrice|B|', 'Ruggeri|Loredana|L|', 'Urbani|Elena|E|', 'Baldoni|Stefano|S|', 'Cecchini|Debora|D|', 'Zei|Tiziana|T|', 'Iacucci Ostini|Roberta|R|', 'Crescenzi|Barbara|B|', 'Carotti|Alessandra|A|', 'Pierini|Antonio|A|', 'Sportoletti|Paolo|P|', 'Di Bartolomeo|Paolo|P|', 'Falzetti|Franca|F|', 'Mecucci|Cristina|C|', 'Velardi|Andrea|A|', 'Martelli|Massimo F|MF|', 'Di Ianni|Mauro|M|']
D000818:Animals D004195:Disease Models, Animal D006086:Graft vs Host Disease D020544:Graft vs Leukemia Effect D051379:Mice D016688:Mice, Inbred NOD D016513:Mice, SCID D050378:T-Lymphocytes, Regulatory D000075442:Transplantation, Haploidentical
Regulatory T cells Graft-versus-host disease Graft-versus-leukemia Haploidentical transplantation