In Vitro Large-Scale Expansion of Unfractionated Mononucleated Cells of Human Umbilical Cord Blood: Investigation for Clinical-Grade Generation of Cord Blood Hematopoietic Cells.

Abstract Abstract 3222 Poster Board III-159 Previous studies of expansion for hematopoietic stem/progenitor cells showed progenitor cells could reach a great expansion but were mainly performed at small culture volume. The poor cell number of expanded cells even great folds of expansion in a no more than 10 ml culture system limited the application for clinic transplantation. Thereof, we expanded umbilical cord blood (UCB) hematopoietic cells at a large scale in 250 ml bioreactor culture system. The mononuclear cell isolated form fresh UCB samples were ex vivo expanded in 250 ml bioreactor with serum-free medium supplied with SCF, FL3 and TPO at concentration 20 ng/ml. Cell number, surface markers and colony forming potential after 7 days of expansion have been evaluated. The sub-lethally irradiated animal models were used to analyze engraftment capability of HSC by transplant of expanded cells in severe combined immunodeficient and nonobese diabetic (NOD/SCID) mice. The detection of human hematopoietic cells in the bone marrow of the mice was performed at 6 wk after the transplant. We have successfully expanded hematopoietic progenitor cells 5 times using the modified bioreactor. The cell viability showed no obvious variations during culture. Total cells increased from 1.76±0.50 ×108 (range 1.2-2.5) to 4.14±0.83×108 (range 3.7-5.6) after expansion, CD34+ cells from 1.25±0.31 ×106 (range 0.96-1.75) to 3.96±0.78×106 (range 2.88-5.04) and CD133+ cells from 1.55±0.69×106 (range 0.96-2.75) to 4.77±0.88×106 (range 4.00-5.04). The colonies per 105 cells of CFU-E /BFU-E, CFU-GM and CFU-Mix increased from 369.6±71.5 to 1648.5±504.3, 42.8±81.4 to 146.4±54.5, 39.1±10.3 to 144.7±38.8, respectively. The positive expression of CD34+ was 0.7%±0.28% at day 0 and 0.9%±0.34% after culture in bioreactor at day 7 and CD133+ cells was 0.8%±0.24% and 1.1%±0.35%. There was no significant survive rate difference between expanded and nonexpanded cells transplantation group. The analysis of multilineage hematopoiesis showed that transplanted human hematopoietic cells is represented in murine bone marrow cells by detection the percentage of human cells identified with human specific anti CD3/19/33/45/61/71 MoAb by FACS and the human specific gene Alu-1 and Cat-1 by PCR. Disclosures No relevant conflicts of interest to declare.