Fig. 3

Characterization of Fc-fusion protein expression and secretion in wildtype CHO lines. Samples of cell extract (CE) and spent medium (16 h collection) prepared from CHO lines expressing Fc-AP-GLP1 (a) [15 μg (7 %) of CE; 0.9 % of spent medium], Fc-GS-PYY (b) [10 μg (8.5 %) of CE; 1.3 % of spent medium) and Fc-AP-NMU (c) [10 μg (5.3 %) of CE; 1.3 % of spent medium) were fractionated by SDS-PAGE; samples and a human IgG standard were visualized using antibody to human Fc. d Using GeneTools, data from several similar analyses (n = 3–4) were quantified to determine μg Fc/mg cell protein. e The secretion rate for Fc was calculated for several experiments by quantifying the amount of Fc recovered from the cell extract (CE) and from the medium using GeneTools; for each cell line, secretion rate was expressed as % cell content secreted per hour