Creative Biolabs is constantly devoted to seeking and developing novel testing approaches for illustrating an exhaustive picture of antibody mechanism of action (MOA). We now provide our global clients with first-class assay service to detect and quantify the ADCP potency of therapeutic antibody candidates.
Antibody-dependent cellular phagocytosis (ADCP) is one crucial MOA of many antibody therapies. It is defined as a highly regulated process by which antibodies eliminate bound targets via connecting its Fc domain to specific receptors on phagocytic cells, and eliciting phagocytosis. Unlike ADCC, ADCP can be mediated by monocytes, macrophages, neutrophils, and dendritic cells, through FcγRIIa, FcγRI, and FcγRIIIa, of which FcγRIIa (CD32a) on macrophages represent the predominant pathway. However, ADCP is often neglected since the ADCP assays can be extremely tedious to prepare, perform, and reproduce, which are both time- and labor-consuming. Recently, increasing attention has been paid to ADCP as an essential component of the IND submission package. In an effort to address this need, Creative Biolabs brings out our state-of-the-art ADCP evaluation service, allowing a comprehensive analysis of ADCP potential and activity in a robust, reliable, and efficient way.
Fig.1 Mechanisms of action of monoclonal antibodies targeting surface antigens on multiple myeloma cells. (van de Donk, 2016)
This classic ADCP assay format is based on using peripheral blood mononuclear cell (PBMC)-derived macrophages as effector cells. After extraction of fresh human PBMCs, monocytes will be isolated and differentiated in culture to macrophages. The workflow is much more sophisticated than ADCC and usually takes more than one-week period. Phagocytosis events will be analyzed using FACS screening, and a dose-dependent curve will be generated to assess the ADCP potency in detail. Of note, effector cells from distinct donors cannot be pooled due to MHC restrictions. Hence, samples from a battery of donors must be applied to reduce donor-specific variability. Primary ADCP assay can be a powerful tool for early phage confirmation of in vivo ADCP liability, as well as for biocompatibility assessment of biosimilars and biobetters.
Considering the tedious steps in primary ADCP test, Creative Biolabs has introduced a surrogate assay using reporter gene technique, which is more accessible and robust. We employ an engineered Jurkat T cell lines stably expressing FcγRIIa (CD32a) as effector cells. For target cell, we can either deal with custom provided materials or help to select a most suitable one, using our plentiful off the-shelf tumor cell lines. Assay readout will be effector cell activation by measuring the NFAT luminescent level. Reporter-gene assay can reflect the ADCP MOA with improved specificity, sensitivity, accuracy; it can also be established in quality control, drug development settings.
ADCP assays based on primary effector cells are a great tool for reflecting the MOA of a mAb therapeutic during the early phase of drug development, while the reporter ADCP assay allows fast, accurate, reproducible, and cost-saving approach to reflect bioactivity during not only early-phase bio-comparability but also for lot release and stability testing.
Taking together, Creative Biolabs is specialized in conducting ADCP assays and have gained remarkable success in various projects. Our fast, accurate, reproducible and cost-effective platform can deliver compelling data regarding in vivo ADCP bioactivities as well as lot release and stability evaluation. For more detailed information, please feel free to contact us or directly sent us an inquiry.
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