A collagen-based microwell migration assay to study NK-target cell interactions.

Area of Science:

• Immunology
• Cell Biology
• Biophysics

Background:

• Natural killer (NK) cell function in tissues relies on migration through the extracellular matrix (ECM).
• Existing 2D imaging methods fail to replicate in vivo microenvironmental cues affecting NK cell migration and cytotoxicity.
• Understanding NK cell migration in a 3D context is crucial for studying their role in immunity.

Purpose of the Study:

• To develop and validate a novel 3D microwell assay for long-term imaging and tracking of NK cell migration within an ECM-like matrix.
• To investigate the heterogeneity of NK cell motility and migration patterns in a 3D microenvironment.
• To provide a complementary tool for in vivo imaging to study NK cell behavior.

Main Methods:

• Development of a microwell assay enabling long-term imaging of small, defined NK cell populations.
• Incorporation of an interstitial ECM-like matrix to mimic the in vivo microenvironment.
• Long-term imaging and tracking of NK cell-target cell interactions within a confined 3D volume.

Main Results:

• Observed significant heterogeneity in NK cell motility, with some cells exhibiting slow movement and confinement, while others moved more freely.
• Identified transient variations in motility, characterized by alternating periods of migration arrest and active movement in the majority of NK cells.
• Demonstrated the capability of the assay to capture complex migratory behaviors not apparent in 2D models.

Conclusions:

• The developed 3D microwell assay accurately reflects the complex migratory behavior of NK cells within an ECM.
• The findings highlight significant heterogeneity in NK cell migration, impacting their cytotoxic functions.
• This assay serves as a valuable tool to complement in vivo studies of human NK cell migration and cytotoxicity.