A Versatile High-Throughput Single-Cell Screening Platform for Profiling Antigen-Specific Long-Lived B Cells in Blood and Bone Marrow.

Antigen-specific B cells play a crucial role in the long-term immune response following infection or vaccination, differentiating into antibody-secreting cells (ASCs) and memory B cells (MBCs). However, profiling ASCs is challenging primarily due to their lack of membrane-bound surface B cell receptors. In this study, the Modular Superhydrophobic Microwell Array Chip (MoSMAR-chip) is introduced as a versatile, cost-effective, and high-throughput platform for identifying and characterizing individual antigen-specific ASCs and MBCs at the single-cell level within seven days. Using this platform, comprehensive analyses of single ASCs could be performed from bone marrows of coronavirus disease 2019 (COVID-19) vaccine-immunized mice and a diverse set of antibodies capable of neutralizing the highly divergent JN1 variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were identified. These results demonstrate that the MoSMAR-chip facilitates efficient single-cell multi-omics and functional analyses of antigen-specific ASCs, offering a powerful tool for investigating complex long-term B cell immunity in diverse clinical conditions, such as infectious diseases, autoimmunity, and beyond.