Implementation and development of OCTET Red96e BLI platform

Biologics (monoclonal antibodies, bispecific antibodies, antibody-drug conjugates, etc.) are a class of complex molecules used in a wide range of therapeutic indications, including cancers and auto-immune diseases. Characterisation and quality control of this class of products requires the study of the binding to target and immune cell receptors, with innovative techniques such as Surface Plasmon Resonance (SPR – Biacore, Cytiva) or Bio-Layer Interferometry (BLI – Octet, Sartorius). While SPR is a widely accepted technique, already used in a large number of laboratories, BLI is relatively new, especially in the biopharma field. In spite of this “new player” status, more and more laboratories consider BLI as a complementary or alternative technique to SPR. In the same way as SPR, BLI technology offers label-free assays that provide precise and reliable concentration and kinetic measurements. This can be applied throughout all stages of product development, from discovery to quality control, including stability studies and batch-to-batch consistency evaluation.

In this application note, different case studies will be presented such as binding to the target, to Fcy receptors (linked to ADCC mechanism), to FcRn (directly correlated to the half-life of the antibody) or to C1q (leading to CDC mechanism). Finally, an example of concentration assay will also be shown through the dosage of an antibody fragment in order to determine the active concentration of this biomolecule.

Based on all the experiments described in this application note, it can be concluded that BLI technology can be used to characterise several types of interactions for biotherapeutics. Regarding general BLI performance, it can be stated that BLI can both lead to precise kinetics results depending on the interaction studied (but somewhat less precise than that which can be obtained using SPR analysis, see our technical sheet “Surface Plasmon Resonance”), as well as generate accurate and precise results in order to determine the active concentration of a biomolecule.