Sequencing-based approach to measure secreted proteins at single-cell level
Opportunity
Secreted proteins such as cytokines, chemokines, growth factors and antibodies play crucial roles in cellular communication. The measurement of these functional protein release and correlating them to individual source cells can provide important insights to the immune responses in disease states such as cancer, autoimmune disorders, or infectious diseases and accelerate the development of immunotherapies.
Current methodologies that measure secreted protein levels include enzyme-linked immunosorbent assay (ELISA) and Luminex assays. However, these assays measure protein levels at the population level. Intracellular cytokine staining (ICS), whilst it is able to measure single-cell protein expression, is unable to distinguish intracellular from secreted proteins.
Technology
The NUS research team has developed a new technique termed time-resolved assessment of single-cell protein secretion with sequencing (TRAPS-seq) that enables the concurrent measurement of secreted proteins, cell-surface markers and transcriptome at the single-cell level.
The technology involves a high-throughput sequencing-based approach to measuring protein secretion at the single cell level.
In a 2-step sequential process, secreted proteins are first anchored to the cell surface through capture antibodies (CapAbs) developed by the team. The bound target proteins are then detected through oligo-conjugated antibodies in which the oligo barcodes are read and measured through sequencing.
The technique also allows for dynamic tracing and measurement of secreted proteins over time.
Schematic of TRAPS-seq: Cells are pre-coated with cytokine-capturing antibodies (CapAbs) which bind to both cell membrane-anchored CD45 and secreted cytokines or analytes post cell stimulation. The captured Cytokines can be detected by oligo-barcoded antibodies (Ab-oligo) by sequencing
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