Purification of IFNα2b by cation-exchange chromatography. A) A typical chromatographic profile of a purification of HEK293-produced IFNα2b from a 400 mL fed-batch culture is illustrated. Solid line shows the 280 nM absorbance profile. Dotted line shows pH variations. IFNα2b elutes in a single peak between 1000 and 1200 mL. B) Coomassie-stained SDS-PAGE analysis of 20 μL samples collected at different steps of production and purification of IFNα2b. 1- crude harvest. 2- precipitate (equivalent to 200 μL of harvest volume). 3- clarified harvest. 4- flow through SO3- column. 5- wash SO3- column. 6- elution peak SO3- column. 7- desalted IFNα2b in PBS.