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Phenotyping polarization dynamics of immune cells using a lipid droplet-cell pairing microfluidic platform
Léa Pinon1,2,3, Nicolas Ruyssen4, Judith Pineau2
1École Normale Supérieure, UMR 8640, Laboratoire PASTEUR, Département de Chimie, PSL Research University, Sorbonne Université, CNRS, 75005 Paris, France.
Insights
Researchers studied how B cells polarize intracellular components at the immune synapse. They found that antigen concentration and substrate rigidity significantly influence lysosome polarization dynamics.
Area of Science:
- Immunology
- Cell Biology
- Biophysics
Background:
- The immune synapse is crucial for lymphocyte function, involving intracellular component polarization.
- Surface properties of antigen-presenting cells influence synapse formation, but their effect on polarization is less understood.
Purpose of the Study:
- To investigate how surface properties of artificial antigen-presenting cells impact B cell polarization at the immune synapse.
- To quantify the effects of ligand concentration, surface fluidity, and substrate rigidity on lysosome polarization in B cells.
Main Methods:
- Utilized functional lipid droplets as tunable artificial antigen-presenting cells.
- Employed a microfluidic device for simultaneous observation of synchronized immune synapses and B cell polarization.
- Dynamically quantified lysosome polarization patterns in individual B cells.
Main Results:
- Lysosome polarization onset and kinetics are dependent on local antigen concentration at the immune synapse.
- Substrate rigidity was identified as a key factor influencing lysosome polarization.
- The experimental system allowed for fine phenotyping of B cell populations based on synaptic readouts.
Conclusions:
- Local antigen concentration and substrate rigidity are critical regulators of B cell immune synapse polarization.
- The developed system provides a novel platform for dissecting immune synapse dynamics and cell phenotyping.
Abstract:
The immune synapse is the tight contact zone between a lymphocyte and a cell presenting its cognate antigen. This structure serves as a signaling platform and entails a polarization of intracellular components necessary to the immunological function of the cell. While the surface properties of the presenting cell are known to control the formation of the synapse, their impact on polarization has not yet been studied. Using functional lipid droplets as tunable artificial presenting cells combined with a microfluidic pairing device, we simultaneously observe synchronized synapses and dynamically quantify polarization patterns of individual B cells. By assessing how ligand concentration, surface fluidity, and substrate rigidity impact lysosome polarization, we show that its onset and kinetics depend on the local antigen concentration at the synapse and on substrate rigidity. Our experimental system enables a fine phenotyping of monoclonal cell populations based on their synaptic readout.
