IgG FcRs are important mediators of immunity and play a key role during Ab-based immunotherapy. Thus, measuring the binding affinity of Ab-based therapeutics (including Fc fusion proteins) to the Fcγ receptors has become an integral part of their development process. As a leading provider of antibody-related services, Creative Biolabs can provide a full panel of FcγR binding assay services for our worldwide customers based on years of experience and high-end technologies. Here, we focus on the high-affinity FcγRI.
The Fc-γ receptor I (FcγRI), also known as CD64, is a type of receptor that can bind monomeric IgG-type antibodies and immune complexes with high affinity. Actually, FcγRI is an integral membrane glycoprotein containing an extracellular Ig-interactive region of three Ig-like domains, a transmembrane domain, and a short intracellular domain. FcγRIs are mainly expressed on the monocytes, macrophages, neutrophils, dendritic cells, and eosinophils. The expression of FcγRI also can be induced by stimulation with cytokines like interferon-γ (IFN-γ) and/or granulocyte-colony stimulating factor (G-CSF). FcγRIs are activating receptors that can interact with an accessory chain known as the common γ chain, which possesses an immunoreceptor tyrosine-based activating motif (ITAM) that is necessary for triggering cellular activation.
FcγRI mainly function during early immune responses and adaptive immune responses in antibody-dependent cellular cytotoxicity (ADCC) and clearance of immune complexes (IC). Research articles have indicated that FcγRI plays a significant role in protecting the host from bacterial infections based on these critical biological functions. Meanwhile, its high-affinity property facilitates FcγRI to be an important factor in the development of therapeutics for different human diseases.
Fig.1 Fc receptors can have unique Ig specificities. (Maverakis, 2015)
The interaction of Fc fragment with corresponding Fc receptors is of great importance in mediating the effector functions and therapeutic activity of antibodies and Fc-fusion proteins. Creative Biolabs has combined extensive knowledge and experience in antibody-FcR binding assays with multiple state-of-the-art techniques. In terms of FcγRI binding assays, we provide approaches including but not limited to:
Case Study
Fig.2 Binding and fitting curves between sample-1 with FcγRI/CD64 at different concentrations. (Creative Biolabs)
Table.1 SPR result summary between sample-1 with FcγRI/CD64. (Creative Biolabs)
| Method | Ligand | Capture Level (RU) | Analyte | Analyte Conc. | ka (1/Ms) | kd (1/s) | KD (M) | Rmax (RU) | Chi² (RU²) | Fit method |
| His Capture | Human FcγRI/CD64 | 49.4 | Sample-1 | 0.977-125 nM | 3.63E+05 | 1.08E-03 | 2.99E-09 | 95.3 | 4.37 | 1:1 binding |
Creative Biolabs has always been dedicated to the field of antibody development to assist our clients with their scientific research. Our established panel of human Fcγ receptors also includes FcγRIIIa, FcγRIIIb, FcγRIIb, and FcγRIIa. Additionally, we offer FcRn binding assay to study pH-dependent interaction of the antibody with the FcRn. Functional cell-based assays, including antibody-dependent cellular cytotoxicity (ADCC), antibody dependent cellular phagocytosis (ADCP), and complement dependent cytotoxicity (CDC), can also be conducted. The outcome of these studies can enhance the understanding of your antibody candidates and illustrate comparability in the development of biosimilars.
If you have any question, please feel free to contact us or directly sent us an inquiry.
Reference
For Research Use Only.
