Recombinant Human Serum Albumin Expressed In Plants Improves The Productivity And Growth Kinetics Of CHO

Human Serum Albumin (HSA) is a media supplement that improves the growth and productivity of cells in serum-free culture. Albumin has several activities that make it desirable in cell culture: lipid binding, waste and toxic contaminant removal, antioxidant activities, metal carrying, and membrane stabilization. However beneficial, plasma-derived HSA (pHSA) and bovine serum albumin (BSA) are undesirable in bioproduction due to the increased risk of transmitting adventitious infectious agents. Albumin has been reduced or eliminated from the majority of modern production media formulations due to these regulatory concerns.

Due to the increased risk of transmitting infectious agents, antibody production is moving away from the use of animal-derived components in bioproduction. The switch to animal-free cell culture media often results in less performance which is evident in longer doubling time, lower peak cell density and reduced antibody titer. We evaluated recombinant human albumin (rAlbumin, Cellastim S), produced in a non-animal plant host, for its effect in hybridoma cell culture. Cellastim S outperformed plasma-derived HSA (pHSA) in promoting cell growth and antibody titer. The use of Cellastim S resulted in an average 140% increase in cell growth and 92% increase in volumetric antibody productivity across several media formulations. Cellastim S improved the growth of cells in long term culture. In addition, Cellastim S improved the effect of serum withdrawal and eased the transition to chemically defined media.