Characterization of IgGs, the most prevalent class of circulating antibody following vaccination or infection, remains limited by the lack of high-throughput techniques to characterize both the activity and the sequence of antibodies secreted by plasma cells.
More...Characterization of IgGs, the most prevalent class of circulating antibody following vaccination or infection, remains limited by the lack of high-throughput techniques to characterize both the activity and the sequence of antibodies secreted by plasma cells. Here we describe CelliGO, a droplet-based microfluidics system combining high-throughput single-cell screening of millions of IgG-secreting cells, based on the activity of the secreted IgG, with single-cell sequencing of paired antibody V genes. We analyzed IgG repertoire diversity, clonal expansion and somatic hypermutation in mice immunized with a vaccine target, a multifunctional enzyme or a membrane-bound cancer target. Immunization and screening using soluble protein antigens or cells expressing the membrane protein antigen yielded 100-1,000 IgG sequences per mouse. Of the 77 recombinant antibodies tested, 93% bound the soluble antigen and 14% the membrane antigen, with predominantly sub-nanomolar and sub-micromolar affinities, respectively. CelliGO promises to be a powerful tool to investigate immune responses and for therapeutic antibody discovery.
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