2.2.1. Flow-through two column chromatography
The virus removal capability of the Cellufine MAX IB (AEX) and Cellufine DexS HbP (CEX) mini columns (CV of 5 mL) operated in flow-through mode without virus filtration (Figure 4) was evaluated. Following column equilibration, 300 mL of 10 mg/mL mAb (600 mg mAb/mL-resin for each column) spiked with MVM or X-MuLV at 2% and passed through a 0.45 μm PES prefilter was loaded onto the columns at a flow rate of 0.25 mL/min (residence time 20 min) using an AKTA pure 25. Following a 60 min process pause, the columns were flushed with a 30 mL buffer wash. Virus titer assay was conducted on both the 300 mL flow-through fraction and the combined flow-through fraction with the 30 mL buffer wash (Table 1).