Figure 6 SDS-PAGE analysis of medium samples harvested from semi-continuous cultures. Medium samples (10 µL) from cultures seeded at cell densities of 0.5 × 107 cells/mL (A, B)and 1.0 × 107 cells/mL (C, D) were applied to SDS-PAGE analysis under reducing (A, C) and non-reducing(B, D) conditions. Lane MW, molecular weight markers; lanes 1–7, medium samples harvested at day 2 (lane 1), day4 (lane 2), day 6 (lane 3), day 8 (lane 4), day 10 (lane 5), day 12 (lane 6), and day 14 (lane 7); lane N, fresh culture medium; lane P, purified scFv-Fc (2 µg).