Dynamic analysis of immune and cancer cell interactions at single cell level in microfluidic droplets

Abstract

Cell-cell communication mediates immune responses to physiological stimuli at local and systemic levels. Intercellular communication occurs via a direct contact between cells as well as by secretory contact-independent mechanisms. However, there are few existing methods that allow quantitative resolution of contact-dependent and independent cellular processes in a rapid, precisely controlled, and dynamic format. This study utilizes a high-throughput microfluidic droplet array platform to analyze cell-cell interaction and effector functions at single cell level. Controlled encapsulation of distinct heterotypic cell pairs was achieved in a single-step cell loading process. Dynamic analysis of dendritic cell (DC)-T cell interactions demonstrated marked heterogeneity in the type of contact and duration. Non-stimulated DCs and T cells interacted less frequently and more transiently while antigen and chemokine-loaded DCs and T cells depicted highly stable interactions in addition to transient and sequential contact. The effector function of CD8 T cells was assessed via cytolysis of multiple myeloma cell line. Variable cell conjugation periods and killing time were detected irrespective of the activation of T cells, although activated T cells delivered significantly higher cytotoxicity. T cell alloreactivity against the target cells was partially mediated by secretion of interferon gamma, which was abrogated by the addition of a neutralizing antibody. These results suggest that the droplet array-based microfluidic platform is a powerful technique for dynamic phenotypic screening and potentially applicable for evaluation of novel cell-based immunotherapeutic agents.

Analysis of Single-Cell RNA-Seq Identifies Cell-Cell Communication Associated with Tumor Characteristics

“…For instance, only about 20%-25% of patients respond to immuno-oncology drugs (Dempke et al, 2017;Schumacher et al, 2015). This limited response rate is likely because of the complex network of cell-cell interactions present in a tumor microenvironment, our knowledge of which is still incomplete (Sarkar et al, 2016). To better stratify patients for existing therapies as well as to discover interactions that could be targeted, there is a need to more fully understand the spectrum of cell-cell interactions occurring in tumor microenvironments and how these interactions affect outcome.…”

Single-cell technologies for profiling T cells to enable monitoring of immunotherapies

“…Additionally, it can integrate real-time cytokine profiling by bead-based cytokine sensors [80] or gene expression profiling by single cell retrieval via micromanipulator [81] due to the non-destructive feature of this assay. Similarly, it has also been reported that droplets can be used to co-encapsulate the two types of cells before docking to the microwells [82]. This microwell-based device was compatible with live cell imaging analysis, allowing the dynamic monitoring of cell morphology, behavior, and fate.…”

Analysis of Leukocyte Behaviors on Microfluidic Chips

“…C) Droplet‐assisted cell contacts and tumor defeat observation: i) droplets generation on the microchamber chip; ii) time lapse images of DC–T cells interaction in the T‐cell activation process. Reproduced with permission . Copyright 2016, AIP Publishing.…”

“…Other than the sedimentation of cell suspension, cell encapsulation, which is induced by droplet formation, is also helpful for cell loading into the microchambers. Konry and co‐workers trapped T cells along with immature/mature DCs in hydrogel droplets to study T cells' activation (see Figure C). The result showed that mature DCs exhibited higher contact frequency and extended contact period during T‐cell activation process.…”