Monoclonal antibodies and related fragments are the major class of therapeutics currently in development by the biopharmaceutical industry. The bottleneck in the manufacturing of antibodies is the downstream processing, namely, in the Protein A capture step due to the costs associated. Alternative affinity ligands became an attractive strategy because they can display both high selectivity and affinity for antibodies at lower costs. This work reports the discovery of a novel mixed-mode ligand with affinity towards antibodies and fragments. A 72-component library based on the Petasis-Ugi multicomponent reactions was synthetized and screened against polyclonal human IgG. Lead ligand B1Al2A2 was selected with 100% of binding towards IgG and its performance as an antibody purification platform was assessed by verifying the recovery yields and purity when loading human plasma, mammalian and bacterial cell cultures containing Trastuzumab and single-domain antibodies, respectively. B1Al2A2 selectively purifies the target molecules in detriment of other contaminants achieving recoveries between 50-90% and purities within 70-96% under mild elution conditions using sodium phosphate and arginine. Moreover, after the purification step Trastuzumab remains functional by maintaining its recognition for the HER-2 receptor intact. B1Al2A2 is resistant to regeneration cycles with harsh solvents maintaining its selectivity towards IgG. Experiments with the Fc fragment show that the adsorbent preferably interacts with the variable region of antibodies, thus proving the applicability of this adsorbent as a purification platform for immunoglobulins and derived fragments.

Novel adsorbent platform for antibody purification using small synthetic affinity ligands

2019 Spring National Meeting

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