Abstract: A process for purifying human Interleukin-1 receptor antagonist (IL-1ra), obtained by fermenting a strain of recombinant E. coli, which comprises: a) loading the mixture to be purified, which has been buffered at a pH value lower than 6.2 and optionally diluted to reduce its ionic strength at a low value, onto a cationic exchange matrix and eluting said matrix with an aqueous buffered solution having a pH value from about 7.5 to 9.0 and a low ionic strength; and b) applying the eluate from the cationic exchange step, containing the desired IL-1ra protein, directly onto an anionic exchange matrix and eluting with an aqueous buffered solution having a pH value within the above range 7.5 to 9.0 and an increased ionic strength.

Abstract: The present invention is directed to a simple and efficient process for the recovery of a biologically active glycoprotein from a biological fluid containing it.In a preferred embodiment, it comprises:a) contacting a filtered culture fluid with a dihydroxyboronyl bearing chromatographic supportb) eluting with a first eluting buffer and contacting this eluate directly with an anion exchange matrix bearing quaternary ammonium functional groupsc) eluting with a second eluting buffer and collecting the product therefrom.