Purification of full-length antibodies containing an Fc region relies on Protein A affinity chromatography as the golden standard capture step. The well-known robustness, high selectivity and scalability make it an ideal platform technique, minimizing DSP development time to bring new antibodies to market. After monoclonal antibodies (mAbs), various forms of antibody fragments are now becoming the next most important class of protein based therapeutics. These antibody fragments offer new biopharmaceutical opportunities, due to their structural, physiological, and pharmacological properties. Due to the lack of an Fc region, antibody fragments cannot be captured with most engineered Protein A domains. The Amsphere™ A3 Protein A ligand however exhibits high affinity to both the Fc-region as the VH<sub>3</sub>-region of IgGs. Amsphere™ A3 thus offers a Protein A affinity capture step for different VH/VHH containing antibody formats. In this presentation, we explain binding mechanism on a molecular basis for the binding of VH(H) antibody formats to Amsphere™ A3. Binding sites in the Protein A ligand and the VHH and VH molecules are identified and discussed. Dynamic binding capacity data of Amsphere™ for vhh single domain antibodies are compared to other affinity ligand resins in terms of dynamic binding capacity.

Protein A chromatography as capture step for antibody fragments: Mechanism of interaction and case study

253rd National Meeting (2017)

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