Microfluidics-enabled fluorescence-activated cell sorting of single pathogen-specific antibody secreting cells for the rapid discovery of monoclonal antibodies

Abstract

Monoclonal antibodies are increasingly used to prevent and treat viral infections, playing a pivotal role in pandemic response efforts. Antibody secreting cells (ASCs, plasma cells and plasmablasts) are an excellent source of high-affinity antibodies with therapeutic potential. Current methodologies to study antigen-specific ASCs either have low throughput, require expensive and labour-intensive screening or are technically demanding and therefore not accessible to the wider research community. Here, we present a straightforward technology for the rapid discovery of monoclonal antibodies from ASCs: we combine microfluidic encapsulation of single cells into an antibody capture hydrogel with antigen bait sorting by conventional flow cytometry. With our technology, we screened millions of mouse and human ASCs and obtained anti-SARS-CoV-2 monoclonal antibodies with high affinity (pM) and neutralising capacity (<100 ng/mL) in two weeks with a high hit rate (>85%). By facilitating access into the underexplored ASC compartment, we enable fast and efficient antibody discovery as well as immunological studies into the generation of protective antibodies.

Antibodies, repertoires and microdevices in antibody discovery and characterization

“…Fischer et al applied this principle to antibody isolation by generating an agarose-antibody capture matrix. 96 By similarly generating single-cell emulsions of droplets containing reagents and agarose matrix, they were able to identify and sort antibodies directed against different segments of the SARS-Cov2 spike protein, which were captured in the agarose matrix and could be easily sorted upon solidification. Other applications for FACS-based droplet sorting (also called fluorescent-activated droplet sorting (FADS)) include the generation of double emulsion pico-reactors.…”

A Functional Hydrogel Bead-Based High-Throughput Screening System for Mammalian Cells with Enhanced Secretion of Therapeutic Antibodies

“…However, each method has its own limitations in throughput, sensitivity, or accuracy . To address these challenges, alternative approaches involving droplet and HBs microfluidic technology have been explored. ,− A drawback of most of these systems was that cells cannot be recovered and recultured after screening and selection processes.…”