A Microfluidic Chip for Screening and Sequencing of Monoclonal Antibody at a Single-Cell Level.

The pairing of heavy and light chains of an antibody decides the specificity of monoclonal antibodies (mAbs). Acquisition of the genes encoding variable regions of paired heavy and light chains (VH:VL) is crucial, but it is a labor- and cost-intensive process in traditional methods. The emerging microfluidic chips have brought us to a portal of directly acquiring natively paired VH:VL genes by sequencing single target cells. This study presents a novel method in which all processing steps for acquiring natively paired VH:VL genes from single cells are finished in a single microfluidic chip, not multiple discrete devices. The microfluidic chip performs single-cell trapping/in situ fluorescence examination of antibody specificity/cell lysis/gene amplification all at a single-cell level. By a proof-of-concept validation of efficiently acquiring paired VH:VL genes of anti-CD45 mAbs from single hybridoma cells, the microfluidic chip has been proved capable of trapping/screening/lysing single antibody-secreting cells and performing an on-chip reverse transcription-polymerase chain reaction. The presented method has realized remarkably improved cell loss/human labor/time cost, and more importantly, determinacy of native VH:VL gene pairing, which is one of the most decisive factors of effectiveness for antibody discovery.