Abstract 5680: MPSA-AB5000: a high-throughput membrane proteins screening array for therapeutic biologics specificity profiling

Abstract Antibody drug development is lengthy and complex, often hindered by various challenges in clinical advancement. Reports indicate that off-target binding of antibodies may be a significant issue, with approximately 25% of preclinical candidates potentially experiencing these off-target problems. With the rise of new modalities such as CD3 bispecific antibodies, ADCs, and CAR-T therapies, preliminary off-target screening of antibodies has become increasingly important. Despite the use of techniques like immunohistochemistry, ELISA, and flow cytometry (FACS) for off-target testing of antibodies, these methods still exhibit limitations in sensitivity, specificity, and throughput. To address the need for antibody target deconvolution and receptor identification, we developed a novel membrane protein screening array (MPSA) AB5000. MPSA-AB5000 is a high-throughput, cell-based platform for identifying antibody targets and off-targets, enhancing antibody specificity screening and reducing development risks. The MPSA-AB5000 covers diverse human membrane proteins, expressed in live cells to preserve native conformations. C-terminal epitope-tagged clones allow for expression confirmation and cellular localization. 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. Compared to similar technologies, we possess significant advantages in the following aspects: a. High sensitivity and sigh throughput: our technology platform offers not only high sensitivity, capable of detecting subtle interactions but also supports high-throughput screening, allowing for the evaluation of a large number of samples in a short timeframe. b. Avoidance of false negative signals: by eliminating washing steps, our method reduces the risk of false negative signals, ensuring reliable detection of non-specific binding. c. Comprehensive validation approaches: we employ various validation methods such as FACS and ELISA to eliminate false positive signals, enhancing the accuracy and credibility of our results. All the advantages ensure that MPSA-AB5000 is more rapid, simple, and highly sensitive than traditional assays. Citation Format: Liping Wang, Yuanyuan Sun, Guoqian Wang, Jinying Ning, Feng Hao. MPSA-AB5000: a high-throughput membrane proteins screening array for therapeutic biologics specificity profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5680.