Single‐Cell Profiling Reveals Functional Heterogeneity and Serial Killing in Human Peripheral and Ex Vivo‐Generated CD34+ Progenitor‐Derived Natural Killer Cells

Abstract

Increasing evidence suggest that Natural killer (NK) cells are composed of distinct functional subsets. This multi-functional role displayed by NK cells have made them an attractive choice for anti-cancer immunotherapy. A functional NK cell repertoire is generated through cellular education, resulting in heterogeneous NK cell population with distinct capabilities to respond to different stimuli. The application of a high-throughput droplet-based microfluidic platform allows monitoring of NK cell-target cell interactions at single-cell level and in real-time.Through fluorescence-based screening of around 80,000 droplets, with different Effector:Target ratios, a fully automated image analysis allows for the assessment of individual killing events in each droplet over time. We observed a variable response of single NK cells towards different target cells and identified a distinct population of NK cells capable of inducing multiple target lysis, coined as serial killers. To meet the increasing clinical demand for NK cells several sources, such as umbilical cord blood (UCB), have successfully been explored. By assessing the cytotoxic dynamics, we showed that single UCB-derived CD34+ hematopoietic progenitor (HPC)-NK cells display superior anti-tumor cytotoxicity.Additionally, with an integrated analysis of cytotoxicity and cytokine secretion we showed that target cell interactions augmented cytotoxic as well as secretory behavior of NK cells. By providing an in-depth assessment over NK cell functions, this study provides crucial information on diversity and functional characteristics of peripheral blood NK cells and ex vivo-generated HPC-NK cells to develop and improve of NK cell-based cancer immunotherapy.

Qualitative monitoring of SARS-CoV-2 mRNA vaccination in humans using droplet microfluidics

“…This study is the second application of DropMap to monitor human IgG-SCs, with several consistent findings regarding IgG-SC physiology between 2 different antigens (a human glycoprotein [ 28 ] versus a viral surface protein) and models driving IgG-SC generation (autoimmunity versus immunization). DropMap has also been used in other aspects of immune monitoring, including cytokine secretion by T cells from healthy or sepsis patients ( 26 ) and cytokine secretion and cytotoxicity from single human NK cells ( 27 , 41 ). Despite the advantages afforded by droplet microfluidic techniques, it should be noted that such analyses require precise fabrication of imaging apparatuses and microfluidics consumables, which are currently not commercially available.…”