Antibodies are antibodies to a type of special immunoglobulins (Immunoglobulin, Ig) produced by the immune system's B lymphocytes. Antibodies, as the largest immune molecule in the body, can recognise and attack antigens, and they constitute a crucial component of the human immune defence. Therapeutic antibodies therefore represent one of the most promising therapies available in biomedicine today.
Despite these human Igs' designations as IgA, IgD, IgE, IgG and IgM, of all the antibody classes, IgG is the most popular therapeutic antibody to date.
| Category | Main Distribution | Structure | Main Function | Structural Features | Industrialization Features |
|---|---|---|---|---|---|
| IgG | Serum | Monomer |
Neutralizes toxins Placental transfer |
|
|
| IgM | Blood, lymph | Pentamer |
Early infection response Complement activation |
|
High development difficulty |
| IgD | B cell surface | Monomer | Promotes B cell maturation |
|
Rarely developed |
| IgE | Serum (low concentration) | Monomer |
Involved in allergic reactions Anti-parasite |
|
High development difficulty |
One of the most widely used antibodies, IgG, has a central Y-shaped protein divided into two large parts – Fab and Fc. Fab is an antigen-binding region, Fc is an effector region of IgG, such as complement activation (CDC), antibody-dependent cellular phagocytosis (ADCP), and antibody-dependent cell cytotoxicity (ADCC). As far as therapeutic antibodies are concerned, the Fc region can act as a critical check on their safety and effectiveness. Thus, Fc activity must be strictly controlled when it comes to building and generating antibodies.
Figure 1 IgG structure diagram.1
Therapeutic Fc characterization services are essential for optimizing antibody efficacy and safety, helping to ensure that antibody drugs exhibit good in vivo stability and ideal immune effects during treatment.
Common therapeutic Fc characterization services and corresponding technologies/platforms mainly include the following:
| Characterization Category | Specific Project | Main Analysis Technologies/Platforms |
|---|---|---|
| Fc Receptor Binding Analysis | Fc-Gamma Receptor Binding Assays |
|
| FcRn Binding Assays |
|
|
| C1q Binding Assays |
|
|
| Physicochemical Property Analysis | Structural Integrity |
|
| Multimer And Aggregation State Analysis |
|
|
| Glycosylation Analysis |
|
|
| Thermal Stability |
|
|
| Ph Stability |
|
|
| Effect Function Analysis | ADCC Activity |
|
| CDC Activity |
|
|
| ADCP Activity |
|
|
| Neutralization Activity |
|
|
| Complement Binding Ability |
|
|
| Pharmacokinetics | Serum Half-Life |
|
| Tissue Distribution |
|
|
| Clearance Rate |
|
|
| Bioavailability |
|
|
| Immunogenicity Assessment | T Cell Epitope Prediction |
|
| B Cell Epitope Analysis |
|
|
| Anti-Drug Antibody Detection |
|
|
| Cross-Reactivity Analysis |
|
By interacting with various immune system molecules, Fc allows antibodies to gain a diverse suite of effector activities. These are what enable antibodies to not only effectively recognise antigens but also kill pathogens and manage immune activity, thus becoming part of the body's defence system.
When antibodies react to a target, the Fc-side of the antibody recognizes and attaches to Fc receptors on phagocytes (macrophages and neutrophils). This interaction calls forth phagocytes, which eat the antibody-tagged target cells or organisms and decompose them in lysosomes. The process clears away pathogens, apoptotic cells and immune complexes from the body.
NK cells would release cytotoxic chemicals such as perforin and granzymes if the FcRIIIA (CD16) receptor on the surface of the cell recognises and binds to the Fc part of antibodies already anchored to the target. These effector molecules kill and lyse the target cell, which is why the vast majority of therapeutic monoclonal antibodies work as an antitumour agent.
Antibodies that identify target cells can bind with the CH2 segment of their Fc domain and activate the complement protein C1q, initiating a cascade in the normal complement chain. All these reactions eventually form membrane attack complexes (MAC) that create holes in the cell wall, breaking open the membrane and causing cell death.
When an antibody's Fc component crosses inhibitory Fc receptors (eg, FcRIIB) on immune cells, it sends an inhibitory signal within the cell, which blocks immune cell activation. This negative regulatory effect plays an important role in immune regulation and tolerance, avoiding overreactions.
The FcRn receptor is only able to bind to the Fc domain of IgG under acidic conditions (pH 6.0-6.5), thereby allowing IgG to pass through epithelial layers, protect IgG from degradation, and dramatically extend the half-life of IgG in the body. It is necessary to provide maternal IgG to the foetus through the placenta and to keep IgG levels high throughout the body.
As one of the largest antibody development companies in the world, Creative Biolabs appreciates the importance of antibody structure and function. We also research the myriad immune effector activities that the Fc segment executes on antibody molecules. Not only do we offer functional testing and analysis services to our customers, but we try to optimise and increase the therapeutic potential of antibodies by leveraging Fc engineering technology.
With rich experience in antibody research and development, Creative Biolabs provides comprehensive and professional therapeutic Fc characterization services to customers around the world. Our service advantages include:
Integrate advanced analytical technologies such as SPR, flow cytometry, and bio-layer interference to build a complete characterization system. It can achieve all-round analysis from molecular to cellular levels and support the research needs of high-throughput screening and precise characterization.
Based on years of technical accumulation, a standardized experimental process and evaluation system are established. Multiple verification methods are used to ensure data reliability, and a complete data analysis and interpretation system is equipped.
Provide personalized characterization solutions according to project requirements, equipped with rich experimental model resources. Flexible support for diverse research needs from small-scale screening to large-scale characterization.
Follow industry standards and implement comprehensive quality control processes. Equipped with a dedicated quality supervision team to ensure the reliability of experimental data and the standardization of reports.
With an experienced professional team, we provide technical consultation and full project support. Ensure effective project communication and provide customers with the best technical solutions.
Establish a rapid response mechanism and project management system to ensure timely handling of customer needs. Through full tracking, we provide professional data analysis and suggestions.
A: Standard test projects usually take 2-4 weeks to complete, and customized analysis may take longer. The specific cycle depends on the complexity of the test content.
A: Purified antibody samples are required, and the specific concentration and volume requirements vary depending on the test project. Relevant sample background information is also required.
A: Yes, we provide customized services: we can customize analysis plans according to customer needs and provide professional technical consultation.
A: The fee calculation method includes: separate billing by test project, providing an overall project quotation, and discounts can be given based on the number of samples.
A: The cooperation process is as follows: submit a test application form, sign relevant agreements, sample delivery and test implementation, data analysis and report delivery.
Reference
Creative Biolabs provides luciferase-based ADCC assay. This Jurkat cell based assay is pioneered by Creative Biolabs, and the methodology is very well accepted by the field. See attached ADCC Reporter Assay Protocol for further details.
All products and services are for Research Use Only. Do Not use in humans.
ADCC Assay WT vs AfucoTM Mabs Visit
Antibody Fc Engineering: Towards Better Therapeutics Visit
Creative Biolabs has established a team of customer support scientists ready to discuss ADCC/CDC optimization strategies, antibody production, bioinformatics analysis and other molecular biology/biotechnology issues.
