One of the most researched Fc-mediated antibody effector functions is complement-dependent cytotoxicity (CDC), weighing in heavily for successful therapeutic interventions. Creative Biolabs is dedicated to developing and facilitating the field of CDC enhanced antibodies - the key engine for therapeutic antibodies. We have a team of experts who have the most advanced knowledge of CDC enhancement technology. Our proprietary CDC⁺ antibody platform allows antibodies conversion with limited or no chance to mutate to other potent cytotoxic antibodies, thus accelerating your research on different diseases.
CDC is an effector function of IgG and IgM antibodies. When these antibodies bind to surface antigens, CDC is triggered and initiates the formation of membrane attack complex (MAC) and, hence target cell lysis. In the process of the complement cascade, one complement system component, C1q, is involved in binding to the antibody Fc, while the amplification of other components are through alternative pathways. This process is highly dependent on the protein structure of the Fc and the activation mechanism of the complement system, therefore, being a major focus of our CDC enhancement technology.
Fc Protein Engineering Platform
Crosstype™ Engineering Platform
Creative Biolabs already developed a Crea-Tag™ protein that can be co-expressed as the fusion protein. By displacing the complement factor H on tumor cells, together they can activate complement-mediated lysis.
Highlighted Functions of Factor H:
Fig.1 Mode-of-action: Crea-Tag™ displaces the CFH on tumor cells.
Almost identical to the process of optimizing ADCC activity, an engineered Fc protein backbone is used to improve the ability of IgGl antibodies to trigger CDC. Also, it is known that some key amino acids of the complement component C1q can bind to the CH2 domain of IgG1. Creative Biolabs proposes the exchange of all solvent amino acids in the human IgGl Fc domain and alanine can identify various Fc domain variants with increased C1q binding properties. Because of this, we offer a triple variant with a higher C1q binding capacity and stronger CDC activity.
Fig.2 Fc mutation-optimized CD20 antibody shows enhanced complement-dependent cytotoxicity (CDC).
Fig.3 7D8-E345R is a humanized anti-CD20 mAb with engineered Fc region that enhances CDC. 7D8-E345R induced robust antitumor activity in the murine xenograft model.
Creative Biolabs has already established an advanced CDC-enhanced antibody platform—Crosstype™, for the production of Fc engineered therapeutic antibodies. Crosstype™ allows our CDC⁺ antibody Fc region to exhibit a greater binding capacity to C1q while ADCC activity remains unaffected.
The current methods to enhance CDC effect include:
Because antibody-mediated CDC activity is heavily influenced by its subtype, our Crosstype™ platform is based on the IgG1/3 subtype cross-subtype technology, which screens vairous combinations of CH1-hinge-CH2-CH3 while comprehensively evaluateing CDC activity.
Fig.4 Schematic diagram of IgG1/3 cross-subtype.
Highlighted Functions for Engineered Fc Regions:
• Increased CDC function
We are committed to the development of CDC⁺ therapeutic antibodies and hopefully, increasing effector function to improve the therapeutic activities of antibodies.
• Extended half-life
Increasing serum persistence is the key to increase antibody efficacy. The increased half-life allows for higher circulating levels, lower frequency administration and reduced dose during experiements.
Fig.5 CDC Effect of IgG1/IgG3 isotype shuffling on functions of an anti-CD20 antibody.
For more details about our CDC Enhancement Technology service, please do not hesitate to contact us.
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.