2.3. Protein solution characterization
Host cell protein (HCP) in the mAb solution was analyzed using CHO Host
Cell Protein ELISA 3G Kit (Cygnus Technologies).
To determine the molecular weight distribution of proteins, size
exclusion chromatography (SEC) was conducted. For analysis of mAb
solutions, HPLC (Infinity 1260, Agilent) was used with a TSKgel SuperSW
mAb HR column and a column guard (Tosoh). For analysis of plasma IgG
solutions, HPLC (Acquity UPLC, H-Class Plus System, Waters) was
conducted with a TSKgel UltraSW Aggregate column and TSKgel UltraSW
Aggregate Guard column (7.8 mm ID, Tosoh BioScience LLC).
mAb and plasma IgG recovery for chromatography and filtration steps was
determined by measuring UV absorbance at 280 nm before and after
processing steps and calculating recovery as a percentage.