MPSA-AB5000: A high-throughput cell-based membrane protein screening array for accurate early-stage off-target assessment to accelerate safer antibody therapeutic development

Antibody drug development is a lengthy and complex process, often hindered by off-target binding that affects approximately 25-30% of preclinical candidates. With the growing importance of advanced modalities such as CD3 bispecific antibodies, antibody-drug conjugates (ADCs), and CAR-T therapies, early and accurate off-target assessment has become essential. However, conventional assays-including immunohistochemistry (IHC), ELISA, and flow cytometry (FACS)-remain limited in sensitivity, specificity, and throughput.To address these limitations, we developed the Membrane Protein Screening Array (MPSA-AB5000), a high-throughput, cell-based platform for comprehensive identification of antibody targets and off-targets. The MPSA-AB5000 expresses a broad spectrum of human membrane proteins in live cells, maintaining native conformation and post-translational modifications to ensure physiologically relevant binding analysis. MPSA-AB5000 is a high-throughput, cell-based platform for identifying antibody targets and off-targets, enhancing antibody specificity screening and reducing development risks. To provide the highest level of sensitivity, MPSA-AB5000 uses luciferase reporter cell line detection. The wash-free strategy reduces false negatives, and signal amplification makes remarkable discrimination. Furthermore, the platform integrates a Protein A-based reporter system, leveraging Protein A's strong Fc-binding affinity-particularly for human IgG1, IgG2, and IgG4-to immobilize antibodies on reporter cells. This allows detection of off-target-induced signaling even in Fc-modified formats such as IgG1-LALA or IgG4. Collectively, the MPSA-AB5000 provides a robust, versatile, and physiologically relevant solution for antibody target deconvolution and specificity evaluation, accelerating the discovery and optimization of safer antibody therapeutics.