Clinical Grade Isolation of Regulatory T Cells From G-CSF Mobilized PBSC Improves with Initial Depletion of Monocytes.

摘要: Abstract 1176 We have recently demonstrated that G-CSF mobilized peripheral blood stem cells (PBSC) CD4 + CD25 FoxP3 (Tregs) prevent anti-CD34+ hematopoietic T cell alloreactivity in-vitro and co-transplantation of CD34+ Tregs does not affect human engraftment in NOD/SCID mice (Mahmud D et al. Biol Blood Marrow Transplant, 2010). Since only a small number can be isolated from normal we examined whether PBSC useful source for future clinical trials. Five leukapheresis products healthy donors who received rh at 10 ug/kg daily 5 days were processed using the CliniMACS instrument (Miltenyi Biotec, Auburn, CA). CD34 reagent was initially used to isolate cells. To 2-step procedure utilized. A cocktail grade CD14, CD8 CD19 reagents mixed with CD34- depletion monocytes, cytotoxic B obtained by Depletion 2.1 program. The CD4+ then enriched positive selection CD25+ (Miltenyi). Because contain large amount myeloid cells, particularly this scale strategy compared 3-step method included an initial negative CD14+ followed CD8+ CD19+ Prior isolation, average proportion CD4+CD25+ 0.77±0.26% separate products. After process 35±33% (n=3) vs 72±1% after process. Therefore, utilizing approach better yield observed (10 60%). Intracellular expression on 74% Contamination different subsets final largely superior following as isolation method. Contaminating monocytes were, average, 43 5.7%, contaminating 12 1.7% 0.9 0.3%, respectively. In two procedures absolute containing 30 × 9 mononuclear 95 93 6 , These findings clinically available device, suggest may improve purity Treg population PBSC. represent valuable Disclosures: No relevant conflicts interest declare.