Comparison of protein A affinity sorbents III. Life time study.

Protein A affinity chromatography is a popular purification method for immunoglobulins applied at various scales, ranging from micro-tube up to 1000l column format. Three novel high capacity protein A affinity chromatography media have been subjected to a lifetime study using 50 consecutive purification cycles of a cell culture supernatant (CCS) containing a monoclonal antibody. Chromatographic conditions followed protocols used in industrial antibody processing, including stripping and cleaning-in-place of the resins. For all three media, no significant loss of purification performance (measured by sodium dodecylsulfate polyacrylamide gel electrophoresis and analytical size-exclusion chromatography (SEC)) could be observed over 50 cycles. Eluate samples were analyzed for leaked protein A and host cell protein (HCP) content. MabSelect SuRe, the first protein A affinity medium compatible with alkaline regeneration conditions, exhibited the lowest leakage levels, in the range of 1-3 ppm. For the media MabSelect Xtra and ProSep-vA Ultra, leakage levels were in the range of 30-40 ppm. Host cell protein content of eluates from MabSelect Xtra and SuRe were between 300 and 700 ppm, whereas for ProSep-vA Ultra 3000-4000 ppm was achieved.