Strategies to Screen Anti‐AQP4 Antibodies from Yeast Surface Display Libraries

Abstract

A rapid and effective method to identify disease‐specific antibodies from clinical patients is important for understanding autoimmune diseases and for the development of effective disease therapies. In neuromyelitis optica (NMO), the identification of antibodies targeting the aquaporin‐ 4 (AQP4) membrane protein traditionally involves the labor‐intensive and time‐consuming process of single B‐cell sorting, followed by antibody cloning, expression, purification, and analysis for anti‐ AQP4 activity. To accelerate patient‐specific antibody discovery, we compared two unique ap-proaches for screening anti‐AQP4 antibodies from yeast antibody surface display libraries. Our first approach, cell‐based biopanning, has strong advantages for its cell‐based display of native mem-brane‐bound AQP4 antigens and is inexpensive and simple to perform. Our second approach, FACS screening using solubilized AQP4 antigens, permits real‐time population analysis and precision sorting for specific antibody binding parameters. We found that both cell‐based biopanning and FACS screening were effective for the enrichment of AQP4‐binding clones. These screening tech-niques will enable library‐scale functional interrogation of large natively paired antibody libraries for comprehensive analysis of anti‐AQP4 antibodies in clinical samples and for robust therapeutic discovery campaigns.