High throughput screening of mixed-mode sorbents and optimisation using pre-packed lab-scale columns for the purification of the recombinant allergen rBet v 1a

Mixed-mode chromatography was investigated for the purification of the recombinant allergen rBet v 1a expressed in Escherichia coli (E. coli) and used as an active principle for specific immunotherapy (SIT) treatment against birch pollen allergy. The screening of micro-volumes of three mixed-mode sorbents established that rBet v 1a could be captured without any pre-treatment of the crude feedstock on HEA or PPA HyperCel sorbents equilibrated in “physiological-like” conditions. On a mini-column pre-packed with PPA HyperCel sorbent, rBet v 1a was recovered at pH 4, partially separated from a major methionine Bet v 1 contaminant and purified approximately 9-fold in a single step (85% purity).