Creative Biolabs has been working on the development of correct assays to help our clients understand the properties and functions of their candidate monoclonal antibody (mAb)-based therapeutics. Especially, we have the capacity of providing a full range of FcγR binding assays with the highest quality and the most competitive price for global clients.
The Fc-γ receptor IIb (FcγRIIb), also known as CD32b, is the only inhibitory Fc receptor with low-affinity for Immunoglobulin G. FcγRIIb is a type I transmembrane receptor mainly expressed by immune cells, including B cells, dendritic cells, activated neutrophils, macrophages, basophils, and mast cells. In human, FcγRIIb presents a series of inhibitory activities in immunologic processes, such as (i) decrease antibody production and thus inhibits humoral immunity when expressed on B cells, (ii) prevent inappropriate maturation and immunogenic antigen presentation when expressed on dendritic cells, and (iii) inhibit other functions of FcγRs activation, like FcγR-mediated phagocytosis, the release of cytokines, and other pro-inflammatory mediators when expressed on other immune cells. Among these, FcγRIIb is particularly important in inhibiting B cell receptor-mediated activation and maintaining B cell tolerance since FcγRIIb is the principal FcγR expressed on B cells.
Mutations in the FCGR2B gene or abnormity of FcγRIIBs in humans can be associated with different infectious and autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, Goodpasture’s disease, idiopathic thrombocytopenic purpura, and so forth. Moreover, increasing evidence has indicated that antibodies that specifically bind FcγRIIb are useful in treating B cell and plasma cell malignancies.
Fig.1 The functions of FcγRIIB. (Smith, 2010)
FcγR binding assays are approaches that assist in the assessment of the kinetics of antibody-based therapeutics binding to FcγRs. In order to in-depth study the binding properties of therapeutic antibodies to the low-affinity human FcγRIIb as well as detect factors (e.g., glycosylation) affecting FcγR binding, Creative Biolabs has constructed a comprehensive testing platform that encompasses different methods to provide better and customized services to our global clients.
Case Study
Case Study
Fig.2 Binding and fitting curves between sample-1 with FcγRIIb/CD32b at different concentrations. (Creative Biolabs)
Table.1 SPR result summary between sample-1 with FcγRIIb/CD32b. (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 FcγRIIb/CD32b | 43.2 | Sample-1 | 78.125-20000 nM | NA | NA | 1.30E-05 | 127.4 | 0.30 | Steady-state affinity |
With extensive experience and comprehensive technology platforms, Creative Biolabs is a senior expert in the antibody development industry for many years. We are able to provide a full panel of antibody Fc functional assays, which include cell-based cytotoxicity assay services like antibody-dependent cytotoxicity (ADCC), antibody dependent cellular phagocytosis (ADCP), and complement dependent cytotoxicity (CDC), as well as non-cell based FcγRs binding (FcγRIIIa, FcγRIIIb, FcγRIIa, FcγRI), FcRn, and complement protein C1q assay services.
We believe that our high-quality services will help you get through many thorny issues of Fc function analysis. Please feel free to contact us or send us an inquiry for more details!
Reference
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