RESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Mining the antibody repertoire of plasma cells and plasmablasts could enable the discovery of useful antibodies for therapeutic or research purposes1. We present a method for high-throughput, single-cell screening of IgG-secreting primary cells to characterize antibody binding to soluble and membrane-bound antigens. CelliGO is a droplet microfluidics system that combines high-throughput screening for IgG activity, using fluorescence-based in-droplet single-cell bioassays2, with sequencing of paired antibody V genes, using in-droplet single-cell barcoded reverse transcription. We analyzed IgG repertoire diversity, clonal expansion and somatic hypermutation in cells from mice immunized with a vaccine target, a multifunctional enzyme or a membrane-bound cancer target. Immunization with these antigens yielded 100-1,000 IgG sequences per mouse. We generated 77 recombinant antibodies from the identified sequences and found that 93% recognized the soluble antigen and 14% the membrane antigen. The platform also allowed recovery of ~450-900 IgG sequences from ~2,200 IgG-secreting activated human memory B cells, activated ex vivo, demonstrating its versatility.
Assuntos
Anticorpos/genética , Sequenciamento de Nucleotídeos em Larga Escala , Técnicas Analíticas Microfluídicas/instrumentação , Análise de Célula Única , Animais , Antígenos/imunologia , Linfócitos B/imunologia , Vacinas Anticâncer/imunologia , DNA/análise , DNA/genética , Sequenciamento de Nucleotídeos em Larga Escala/instrumentação , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Imunoglobulina G/genética , Camundongos , Análise de Célula Única/instrumentação , Análise de Célula Única/métodosRESUMO
Studies of the dynamics of the antibody-mediated immune response have been hampered by the absence of quantitative, high-throughput systems to analyze individual antibody-secreting cells. Here we describe a simple microfluidic system, DropMap, in which single cells are compartmentalized in tens of thousands of 40-pL droplets and analyzed in two-dimensional droplet arrays using a fluorescence relocation-based immunoassay. Using DropMap, we characterized antibody-secreting cells in mice immunized with tetanus toxoid (TT) over a 7-week protocol, simultaneously analyzing the secretion rate and affinity of IgG from over 0.5 million individual cells enriched from spleen and bone marrow. Immunization resulted in dramatic increases in the range of both single-cell secretion rates and affinities, which spanned at maximum 3 and 4 logs, respectively. We observed differences over time in dynamics of secretion rate and affinity within and between anatomical compartments. This system will not only enable immune monitoring and optimization of immunization and vaccination protocols but also potentiate antibody screening.
