A New Microfluidic Platform for Studying Natural Killer Cell and Dendritic Cell Interactions.

Jolly Hipolito,Sam Kung,Francis Lin,Ke Yang,Hagit Peretz-Soroka,Manli Zhang,Soheila Karimi-Abdolrezaee

doi:10.3390/mi10120851

Abstract

The importance of the bi-directional natural killer–dendritic cell crosstalk in coordinating anti-tumour and anti-microbial responses in vivo has been well established. However, physical parameters associated with natural killer–dendritic cell interactions have not been fully elucidated. We have previously used a simple “Y” shaped microfluidic device to study natural killer cell-migratory responses toward chemical gradients from a conditioned medium of dendritic cells. There are, however, limitations of the Y-shaped microfluidic devices that could not support higher throughput analyses and studies of cell–cell interactions. Here, we report two novel microfluidic devices (D3-Chip, T2-Chip) we applied in advanced studies of natural killer-cell migrations and their interactions with dendritic cells in vitro. The D3-Chip is an improved version of the previously published Y-shaped device that supports high-throughput analyses and docking of the cells of interest in the migration assay before they are exposed to a chemical gradient. The T2-Chip is created to support analyses of natural killer–dendritic cell cell–cell interactions without the requirement of promoting a natural killer cell to migrate long distances to find a loaded dendritic cell in the device. Using these two microfluidic platforms, we observe quantitative differences in the abilities of the immature and lipopolysaccharide-activated mature dendritic cells to interact with activated natural killer cells. The contact time between the activated natural killer cells and immature dendritic cells is significantly longer than that of the mature dendritic cells. There is a significantly higher frequency of an immature dendritic cell coming into contact with multiple natural killer cells and/or making multiple simultaneous contacts with multiple natural killer cells. To contrast, an activated natural killer cell has a significantly higher frequency of coming into contact with the mature dendritic cells than immature dendritic cells. Collectively, these differences in natural killer–dendritic cell interactions may underlie the differential maturation of immature dendritic cells by activated natural killer cells. Further applications of these microfluidic devices in studying natural killer–dendritic cell crosstalk under defined microenvironments shall enrich our understanding of the functional regulations of natural killer cells and dendritic cells in the natural killer–dendritic cell crosstalk.

Highlights

Regulation of immune cell migrations to proper microenvironments is critical for development of specific cell types and/or induction of specific immune responses [1]
natural killer (NK) cells interact with dendritic cells (DC), a critical cell type that regulates adaptive immunity [8,9]
DC produce a number of chemokines to induce NK-cell migrations [10,11]

Summary

Introduction

Regulation of immune cell migrations to proper microenvironments is critical for development of specific cell types and/or induction of specific immune responses [1]. NK cells interact with dendritic cells (DC), a critical cell type that regulates adaptive immunity [8,9]. There are, limitations of the Y-shaped microfluidic devices It includes the requirement of external syringe pumps for chemical flow infusion, relatively low throughput, and the difficulty in configuring different cell types together in the device to facilitate cell–cell interaction studies. The inability to control the initial start positions of cells on a defined gradient profile result in NK cells having a slightly different chemical concentration at their initial positions. The latter might affect analyses of cell migrations in weak chemotactic conditions. We report our recent technical development of two novel microfluidic devices (D3-Chip, T2-Chip) to further advance studies of NK-cell migrations and their interactions with dendritic cells in vitro

Materials and Methods

Microfluidic Device Preparation

Cell Migration and Cell–Cell Interaction Experiments

Data Analysis

Results

The Use of a Novel T2-Chip to Further Examine NK–DC Interactions