Primary ADCP Assay

Functional analysis and characterization that reflect the drug’s mechanism of action (MOA) are required in the process of antibody drug discovery, to ensure efficacy and safety. Currently, Creative Biolabs offers a wide range of service portfolio to support new innovator or biosimilar therapeutic antibody development, including functional cell-based assays that allow the evaluation of antibody-dependent cell-mediated phagocytosis (ADCP).

Introduction to ADCP

Monoclonal antibodies (mAbs) are a booming group of biotherapeutics which have been successfully utilized in clinical practice for the treatment of cancer and autoimmune diseases. The targeted killing action of immune effector cells to the diseased cell is one of the vital MOAs for naked therapeutic antibodies, which is realized by the interaction of the Fc domain of the antibody with the complement component C1q or Fcγ receptors. However, many of these antibodies have failed in the clinic due to poor efficacy.

In order to develop more potent therapeutic mAbs, their biological effector functions should be considered to be increased through the enhancement or reduction in their ability to mediate cellular cytotoxicity functions such as ADCP. ADCP, briefly speaking, is the mechanism by which antibody activates the macrophages by binding to the FcγRs, thereby inducing phagocytosis and lysosomal degradation of tumor cells (Fig.1).

Fig.1 Anti-tumour mechanisms mediated by IgG-FcγR interactions. (Weiner, 2010)

Factors Affecting Antibody ADCP Activity

• Glycosylation state - Antibodies are glycosylated and different glycoforms result in distinct effector functions, including antibody-dependent cell cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Afucosylated antibodies that do not contain the sugar fucose on the oligosaccharide chain at the Asparagine 297 site have been proved to exhibit stronger ADCP activity.
• Effector cell subtype - Different types of effector cells are involved in ADCP, including monocytes, macrophages, neutrophils, and dendritic cells, through different Fc receptors. Thus, the type of effector cells affects ADCP activity.
• Fc receptor polymorphism - The FcγRIIa and FcγRIIIa have polymorphisms that have been linked with clinical outcome. Alleles that are associated with the high-affinity receptors bind antibodies stronger, resulting in better effector function.

Primary ADCP Assay at Creative Biolabs

For the classical primary ADCP assay, monocytes derived from PBMC of healthy donors by negative selection are utilized as effector cells after differentiation to M2 macrophages. Our scientists have developed robust and highly accurate primary ADCP assay formats reflecting activity via CD32 and CD64, using genotyped donors. Our services are characterized by:

• Stable and sufficient human peripheral blood supply from multiple donors
• Effector cell genotyping regarding the FcγRIIIa 158 V/F polymorphism
• A large panel of target tumor cell lines to be used in ADCC assays
• GLP-compliant service upon request
• Flexible assay design that can be readily customized to fit your project

Based on our versatile menu of assays, flexible technology platforms, and comprehensive scientific expertise, Creative Biolabs is able to provide a wide range of bioassay services to evaluate the interaction of antibodies with Fc receptors to modify specific immune cell-mediated interactions depending on the specific research requirements of our clients.

Now, we provide two distinct well-established assay formats for ADCP evaluating:

• Primary ADCP Assay
• ADCP Reporter Bioassay

In addition to ADCP assays, Creative Biolabs also offers the following services regarding Fc-mediated Effector Functional Assays:

If you have any special needs in primary ADCP assays or be interested in learning more about Creative Biolabs’ ADCP assay services, please contact us for more information.

Reference

1. Weiner, L. M.; et al. Monoclonal antibodies: versatile platforms for cancer immunotherapy. Nature Reviews Immunology. 2010, 10(5), p.317.

For Research Use Only.