Characterizing a novel adult erythroid cell line for red blood cell manufacture

Abstract One way to address the growing shortage of donated blood required for routine and emergency transfusion is to mass‐manufacture red blood cells (RBCs) in vitro. However, numerous biological and bioprocessing challenges must be overcome to realize this goal. In addressing these challenges, a promising solution is the erythroid progenitor cell line, BEL‐A (Bristol Erythroid Line—Adult). Despite this, BEL‐A cells are a recent creation and are currently poorly characterized, which is essential to identify the bioprocess necessary for their mass manufacture. To address this knowledge gap, we provide the first work to characterize BEL‐A cell growth, metabolic kinetics, and tolerance to inhibitory metabolites. Our detailed characterization shows that under static batch culture, BEL‐A cell numbers decline beyond 70 h, which cannot be explained by exhaustion of glucose, glutamine, or doxycycline; excess lactate or ammonia; or by pH. BEL‐A cell viability was shown to be more sensitive to ammonia than lactate, while combinatorial concentrations of 2640 mg/L lactate and 129 mg/L ammonia mediated cell death. Finally, daily media replenishment was able to overcome the 70 h proliferation limit, enabling higher density cultures. As a result, we report for the first time the key cellular characteristics crucial for facilitating high‐density BEL‐A cell manufacture within bioreactors, at scale and identify optimal conditions for their in vitro culture. This study therefore represents a critical step in realizing BEL‐A cells' clinical potential as a cell source for large‐scale manufacture of RBCs.