The role of intermolecular interactions on monoclonal antibody filtration through virus removal membranes.

The removal of viruses by filtration is a critical unit operation to ensure the overall safety of monoclonal antibody (mAb) products. Many mAbs show very low filtrate flux during virus removal filtration, although there are still significant uncertainties regarding both the mechanisms and antibody properties that determine the filtration behavior. Experiments were performed with three highly purified mAbs through three different commercial virus filters (Viresolve Pro, Viresolve NFP, and Pegasus SV4) with different pore structures and chemistries.

Role of membrane structure on the filtrate flux during monoclonal antibody filtration through virus retentive membranes.

Virus removal filtration is a critical step in the manufacture of monoclonal antibody products, providing a robust size-based removal of both enveloped and non-enveloped viruses. Many monoclonal antibodies show very large reductions in filtrate flux during virus filtration, with the mechanisms governing this behavior and its dependence on the properties of the virus filter and antibody remaining largely unknown. Experiments were performed using the highly asymmetric Viresolve® Pro and the relatively homogeneous Pegasus™ SV4 virus filters using a highly purified monoclonal antibody.

Virus inactivation at moderately low pH varies with virus and buffer properties.

Background: Virus inactivation is a critical operation in therapeutic protein manufacturing. Low pH buffers are a widely used strategy to ensure robust enveloped virus clearance. However, the choice of model virus can give varying results in viral clearance studies.

Physiochemical properties of enveloped viruses and arginine dictate inactivation.

Background: Therapeutic protein manufacturing would benefit by having an arsenal of ways to inactivate viruses. There have been many publications on the virus inactivation ability of arginine at pH 4.0, but the mechanism of this inactivation is unknown.

Strategies for high-concentration drug substance manufacturing to facilitate subcutaneous administration: A review.

To achieve the high protein concentrations required for subcutaneous administration of biologic therapeutics, numerous manufacturing process challenges are often encountered. From an operational perspective, high protein concentrations result in highly viscous solutions, which can cause pressure increases during ultrafiltration. This can also lead to low flux during ultrafiltration and sterile filtration, resulting in long processing times.

Implementation of an experimental and computational tool set to study protein-mAb interactions.

This work focused on the development of a combined experimental and computational tool set to study protein-mAb interactions. A model protein library was first screened using cross interaction chromatography to identify proteins with the strongest retention. Fluorescence polarization was then employed to study the interactions and thermodynamics of the selected proteins-lactoferrin, pyruvate kinase, and ribonuclease B with the mAb.

Investigation of cathepsin D-mAb interactions using a combined experimental and computational tool set.

Cathepsin D has been identified as a challenge to remove in downstream bioprocessing of monoclonal antibodies (mAbs) due to interactions with some mAbs. This study focused on investigating the mechanisms of interaction between cathepsin D and two industrial mAbs using a combined experimental and computational approach. Surface plasmon resonance was used to study the impact of pH and salt concentration on these protein-protein interactions.

Protein Binding Kinetics in Multimodal Systems: Implications for Protein Separations.

In this work, quartz crystal microbalance with dissipation (QCM-D) was employed to study the kinetic processes involved in the interaction of proteins with self-assembled monolayers (SAMs) of multimodal (MM) ligands. SAMs were fabricated to mimic two chromatographic multimodal resins with varying accessibility of the aromatic moiety to provide a well-defined model system. Kinetic parameters were determined for two different proteins in the presence of the arginine and guanidine and a comparison was made with chromatographic retention data.

Conformational differences between two amyloid β oligomers of similar size and dissimilar toxicity.

Several protein conformational disorders (Parkinson and prion diseases) are linked to aberrant folding of proteins into prefibrillar oligomers and amyloid fibrils. Although prefibrillar oligomers are more toxic than their fibrillar counterparts, it is difficult to decouple the origin of their dissimilar toxicity because oligomers and fibrils differ both in terms of structure and size. Here we report the characterization of two oligomers of the 42-residue amyloid β (Aβ42) peptide associated with Alzheimer disease that possess similar size and dissimilar toxicity.