Benchmarking of Scale-X Bioreactor System in Lentiviral and Adenoviral Vector Production

Abstract

We have previously produced viral vectors (lentiviral vector, adenoviral vector, and adeno-associated viral vector) in small and in commercial scale in adherent cells using Pall fixed-bed iCELLis^® bioreactor. Recently, a company called Univercells has launched a new fixed-bed bioreactor with the same cell growth surface matrix material, but with different fixed-bed structure than is used in iCELLis bioreactor. We sought to compare the new scale-X™ hydro bioreactor (2.4 m²) and iCELLis Nano system (2.67 m²) to see if the difference has any effect on cell growth or lentiviral vector and adenoviral vector productivity. Runs were performed using parameters optimized for viral vector production in iCELLis Nano bioreactor. Cell growth was monitored by counting nuclei, as well as by following glucose consumption and lactate production. In both bioreactor systems, cells grew well, and the cell distribution was found quite homogeneous in scale-X bioreactor. Univercells scale-X bioreactor was proven to be at least equally efficient or even improved in both lentiviral vector and adenoviral vector production. Based on the results, the same protocol and parameters used in viral vector production in iCELLis bioreactor can also be successfully used for the production in scale-X bioreactor system.

Keywords: bioreactor; fixed-bed; iCELLis bioreactor; lentivirus; scale-X bioreactor; virus production.

Figure 1.

Cell counts of dismantled Univercells' scale-X™ hydro bioreactor. Schematic picture of scale-X bioreactor from top (a) and from the side (b). Light gray and dark gray spots indicate the points from which samples were taken for cell density analysis. Light gray = sample of inner membrane, and dark gray = sample of outer membrane layer. For cell density analysis, nuclei were counted from top, middle and, bottom of the fixed-bed, and from the outer surface, middle, and inner surface of the rolled membrane. Cell densities (cells/cm²) are shown in the table below the schematic pictures.

Figure 2.

Cell density and glucose and lactate concentrations in scale-X hydro bioreactor and iCELLis^® Nano bioreactor runs. (a) Cell densities (cells/cm²) calculated from top of the fixed-bed on days 0–4, (b) glucose and (c) lactate concentrations on days 0–7. Control Nano = Nano run, run together with scale-X bioreactor runs. Standard Nano = average of five standard Nano runs. scale-X 1–4 = scale-X bioreactor runs 1–4.

Figure 3.

Scatter dot blot images of media and glucose consumption in scale-X hydro bioreactor and iCELLis Nano bioreactor runs. (a, b) Media consumption before transfections in mL (a) and in μL/cm² (b). (c, d) Total media consumed during the runs until harvest in mL (c) and in μL/cm² (d). (e, f) Glucose consumed until transfection in g (e) and in mg/cm² (f). (g, h) Total glucose consumption until harvest in g (g) and in mg/cm² (h). (i, j) Cell-specific glucose consumption in pmol/cell/day until transfection (i) and until harvest (j), taking into account that after transfection, cell density is not increased. Standard Nano = five standard iCELLis Nano runs aiming at lentiviral vector production, control Nano = run together with scale-X bioreactor runs. scale-X 1–4 = scale-X bioreactor runs 1–4, of which run 1 was not transfected, but run was stopped on day 4 to disassemble the fixed-bed. For standard Nano runs value for each runs is indicated as a separate spot; in addition, SEM and median are shown. SEM, standard error of the mean.

Figure 4.

Lentiviral vector yields in scale-X hydro bioreactor and iCELLis Nano bioreactor runs. (a, b) Total lentiviral particles (vp) and vp/cm² produced, respectively, in scale-X bioreactor and iCELLis Nano bioreactor runs. (c, d) Total TU and TU/cm² produced, respectively, in scale-X bioreactor and iCELLis Nano bioreactor runs. Control Nano = Nano run, run together with scale-X bioreactor runs. Standard Nano = average of five standard Nano runs. scale-X 1–4 = scale-X bioreactor runs 1–4. Mean ± SEM. TU, transducing units; vp, vector particle.