The majority of monoclonal antibody (mAb) therapeutics have been generated and isolated from natural immune systems, typically using mouse or rat hybridoma methods. As targets become increasingly challenging, the ability to look deeply into natural immune repertoire is often critical to unlock therapeutic programs.
AbCellera has developed an end-to-end antibody discovery platform to select monoclonal antibodies with defined properties directly from single B cells. Antibody-secreting cells (ASCs) from patients or immunized animals are loaded into devices containing arrays of nanoliter-volume chambers. Compartmentalization of ASCs in small volume chambers enables the detection of antibody secretion from single cells within hours. The screening platform is integrated within a fully automated instrument that enables the identification and recovery of selected ASCs based on high-throughput automated fluorescent imaging. ASCs with desired antibody properties are identified based on a wide array of multiplexed assays including bead-based binding, specificity and competition, as well as cell-based assays for binding and functional readouts. Single cells of interest are recovered and processed using a next-generation sequencing approach to retrieve the paired heavy and light chain variable region sequences with high efficiency (> 90%). Using a two-step screening process, this platform allows for multi-parameter antibody selections from any species (e.g. human, mice, rat, rabbits, llamas) and from different immune tissue sources (e.g. blood, spleen, bone marrow, lymph nodes), with a routine throughput between 200,000 and 5,000,000 cells screened per run and recovery of over 200 paired sequences in approximately 5 days.
While antibodies from natural immune responses are widely regarded as superior to those generated by display technologies, immune tolerance poses a serious challenge for targets with high inter-species homology. Insoluble and poorly immunogenic targets such as membrane proteins exacerbate this challenge. We show how AbCellera’s ultra-deep screening technology overcomes these challenges, producing hundreds of diverse rodent antibodies against targets with 100% rodent-human homology.