The introduction of affinity-based separations into non-antibody production processes would greatly simplify and shorten the purification train by replacing several non-specific operations (e.g. IEX, HIC, SEC) with a single step. In this study, sets of linear peptides were designed to present complementary physiochemical and structural properties to a targeted region of a non-antibody therapeutic protein. These candidates were screened in a spatially-addressed 2D system of nanoliter spots; the affinity constant (KD), elution conditions and selectivity against host cell protein (HCP) species were all evaluated in this high-throughput manner. This approach identified several lead candidates with affinity and specificity for the target in the presence of cell culture fluid, which were then subjected to additional sequence optimization. Several candidates were conjugated to chromatographic resins and screened in batch adsorption experiments; parameters (KD, HCP selectivity, elution strength) were compared to those obtained at the microscale. Candidates were also screened for product quality attributes (e.g. recovered activity, aggregates and product variants), resistance to proteases and stability in alkaline solutions. Selecting the best candidate, a capture step was developed and evaluated in a small-scale column format. This work shows that a novel affinity purification step using peptide ligands can be rapidly developed using a rational design and screening strategy.

Engineering peptide ligands for the affinity purification of a therapeutic protein

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.