Fc-Gamma Receptor Assays
BioOutsource provides a comprehensive set of off-the-shelf Fc-Gamma Receptor Binding Assays (FcR) to support characterization and release of your product. These assays form part of our antibody evaluation package for measurement of the biological activity and can be supplemented with CDC, ADCC and surrogate ADCC methods to provide critical information on the effector function potential of your product.
The Fc-Gamma Receptors (FcR) are members of the immunoglobulin super family and play a critical role in the function of therapeutic antibodies. The Fc-Gamma Receptors (FcR) can be divided into three types, Fc-Gamma Receptor I (FcGRI/CD64), Fc-Gamma Receptor II (FcGRII/CD32) and Fc-Gamma Receptor III (FcGRIII/CD16). Both the FcRII and FcRIII can be further divided into FcRIIa/FcRIIb and FcRIIIa/FcRIIIb. Historically, these receptors have been categorized based upon their affinity for specific IgG subclasses and whether their binding initiates activating or inhibitory signals. Following binding of antibody to target, the subsequent binding of the FcRs is crucial step for the initiation and control of cell-mediated effector functions of the immune system. Each of the different subclasses of IgG (IgG1, IgG2, IgG3, and IgG4) presents different effector function profiles based upon the differential binding properties to each of the Fc-Gamma Receptors. Whilst FcRI is capable of binding monomeric IgG with high affinity, both FcRII and FcRIII have the capacity to bind IgG complexes and the binding can be affected by genetic polymorphism of the receptors as well as different glycosylation patterns in the Fc region of the the antibody.
BioOutsource performs Fc-Gamma Receptor binding assays for various IgG antibody isotypes using the Biacore T-200 and Biacore 4000, which are versatile, label-free systems with exceptional sensitivity. The Biacore T200 is the most sensitive SPR instrument available from GE Healthcare, and the Biacore 4000 balances high levels of sensitivity with greater sample throughput. We have extensive experience in the performance of biosimilar Fc Receptor binding assays and can apply this experience to novel antibody therapeutics, performing assays with a variety of different positive controls.
We can conduct a range of different Fc Receptor binding studies to evaluate the performance of proteins and antibodies produced from different clones, different production processes or prepared in different formulations. We favour a totality of evidence approach and can generate multiple assay endpoints from each assay reporting the following characteristics of your antibody:
- Full Kinetic Analysis reporting the Binding Affinity Constant (KD) with the association or “on” rate (Ka) and dissociation rate (Kd) or “off” rate
- Steady State analysis reporting Binding Affinity Constant (KD)
- Relative Binding
Our experience in the development and qualification of methods makes BioOutsource the perfect partner to support you as you progress through the clinical phases. Our custom Biacore services include:
- Clone and candidate selection; ranking performed against binding affinity constant, association and dissociation rates
- Quantitation of affinity, association and dissociation rates
- Measurement of Relative Binding & Parallelism