Immortalized Erythroid Line Facilitates Mass Production of RBCs

A robust and reproducible technique allows the production of immortalized erythroid cell lines, which can be cultured indefinitely for large-scale production of red blood cells (RBCs).

Researchers at the University of Bristol immortalized early human adult erythroblasts, which can differentiate efficiently into mature, functional, reticulocytes that can be isolated by filtration. The Bristol Erythroid Line Adult (BEL-A) cell was created from adult bone marrow CD34+cells, which were first transduced and cultured for four days. They were then transferred to expansion medium containing doxycycline to induce expression of E6 and E7, and were maintained in this medium thereafter.

The cells proliferated continuously, achieving a mean doubling time of 20 hours after 100 days in a continuous culture medium. A morphological analysis of the immortalized cells showed them to be pro- to early basophilic erythroblasts, and there was no change in morphology over time. The researchers showed that the erythroid line can fully recapitulate normal erythropoiesis, enucleating to generate mature reticulocytes, the characterization of which revealed no functional differences from normal reticulocytes, even at the molecular level, and with no aberrant protein expression.

According to the researchers, preliminary tests demonstrate similar survival rates to adult donor RBCs in vivo. The technique is robust and reproducible, with multiple additional lines successfully generated, and could allow large-scale and continuous production of RBCs for clinical use. They added that as the BEL-A line is easily transduced, it could also facilitate the development of novel therapeutic products, as well as serve as a superior research tool for the study of erythropoiesis and RBC disease. The study was published on March 14, 2017, in Nature Communications.

“Previous approaches to producing red blood cells have relied on various sources of stem cells which can only presently produce very limited quantities,” said lead author Jan Frayne, PhD, of the University of Bristol School of Biochemistry. “By taking an alternative approach, we have demonstrated a feasible way to sustainably manufacture red cells for clinical use from in vitro culture. Cultured red blood cells have advantages over donor blood, such as reduced risk of infectious disease transmission.”

Blood shortage is a global healthcare problem, and is likely to become even more challenging as people live longer and donor numbers dwindle. Cultured RBCs may provide an alternative to donor blood and hold several potential advantages, such as reduced risk of infectious disease transmission. As the BEL-A cultured cells are all nascent, the number of transfusions administered to patients suffering from sickle cell disease, thalassaemia myelodysplasia, and certain other cancers could be reduced, ameliorating the consequences of organ damage from iron overload.