Using Surface Plasmon Resonance (SPR) to investigate the multi-specific modalities of immunotherapeutic molecules

Multi-specific modalities have expanded the functional capabilities of antibody-based therapeutics. Compared to monospecific antibodies, several individual interactions and their interdependency need to be considered for multi-specific antibodies. 

We have developed an SPR methodology that interrogates binding interdependency of a multi-specific antibody-based therapeutic. We further expanded this approach to demonstrate the impact of Fab arm binding on FcR engagement. This methodology can be applied to a range of molecules from conventional mAbs, bispecific and multi-specific antibody-based therapeutics and fusion proteins as well as to assess the effects of antigen binding on FcR function. For all the insights and data, access our SPR research poster and get in touch with our specialists if we piqued your interest.

What are the benefits of our method?

1. Functional relevance: The assay aims to mimic the formation of the immune-complex between the antibody and the target followed by a second target, aiming to delineate how differently the molecule may behave when one binding arm is engaged.
    
2. Gold-standard equipment: The unique A-B-A functionality of the Biacore 8K allows for the injection of a flanking molecule during sample injection which negates the need for the molecule in the running buffer.
    
3. Precise and accurate data: The assay set-up maintains a constant saturating concentration of one of the binding partners during the multi-cycle kinetic analysis ensuring the data truly represents association and dissociation of only one binding pair.

We have developed a binding dependency assay which allows for the investigation of the multi-specific modalities of immunotherapeutic molecules. The examples presented in the research poster demonstrate how single occupation of an antibody binding domain may affect a ‘cis’ interaction. Understanding binding dependencies is critical for the prediction of functional activity and extends beyond immune cell engagers to all classes of bispecific and multi-specific antibodies and even conventional monoclonal antibodies.