Monitoring T cell-dendritic cell interactions in vivo by intercellular enzymatic labelling
Giulia Pasqual1, Aleksey Chudnovskiy1, Jeroen M J Tas1
1Laboratory of Lymphocyte Dynamics, The Rockefeller University, 1230 York Avenue, New York, New York, USA.
Insights
A new method called LIPSTIC uses bacterial sortase A to label cell-cell interactions in vivo, enabling the study of receptor-ligand dynamics in immune cell partnerships. This technique reveals distinct stages of dendritic cell and T cell interactions during immune responses.
Area of Science:
- Cellular biology
- Immunology
- Molecular biology
Background:
- Cell-cell interactions are crucial for biological processes like immunity and development.
- Intravital microscopy visualizes cell dynamics but doesn't identify specific receptor-ligand interactions or allow cell isolation.
- Existing methods lack the ability to directly measure receptor-ligand interactions and quantify intercellular communication in vivo.
Purpose of the Study:
- To develop a novel method for identifying and analyzing receptor-ligand interactions between cells in living organisms.
- To characterize the distinct modalities of dendritic cell and CD4+ T cell interactions during T cell priming in vivo.
- To provide a flexible tool for quantifying intercellular communication across various biological fields.
Main Methods:
- Bacterial sortase A-mediated cell labelling across immune cell synapses.
- Generation of a detectable signal for ex vivo flow cytometry analysis.
- Application of the 'Labelling Immune Partnerships by SorTagging Intercellular Contacts' (LIPSTIC) approach.
Main Results:
- LIPSTIC successfully labels 'kiss-and-run' interactions between immune cells in vivo.
- Identified two distinct interaction modalities between dendritic cells and CD4+ T cells during T cell priming.
- Demonstrated that early interactions involve cognate CD40-CD40L binding, while later interactions are non-cognate.
Conclusions:
- LIPSTIC enables direct measurement of dynamic cell-cell interactions both in vitro and in vivo.
- The method facilitates the identification of specific receptor-ligand pairs involved in intercellular communication.
- LIPSTIC's flexibility makes it applicable to diverse fields requiring quantification of cell communication.
Abstract:
Interactions between different cell types are essential for multiple biological processes, including immunity, embryonic development and neuronal signalling. Although the dynamics of cell-cell interactions can be monitored in vivo by intravital microscopy, this approach does not provide any information on the receptors and ligands involved or enable the isolation of interacting cells for downstream analysis. Here we describe a complementary approach that uses bacterial sortase A-mediated cell labelling across synapses of immune cells to identify receptor-ligand interactions between cells in living mice, by generating a signal that can subsequently be detected ex vivo by flow cytometry. We call this approach for the labelling of 'kiss-and-run' interactions between immune cells 'Labelling Immune Partnerships by SorTagging Intercellular Contacts' (LIPSTIC). Using LIPSTIC, we show that interactions between dendritic cells and CD4+ T cells during T-cell priming in vivo occur in two distinct modalities: an early, cognate stage, during which CD40-CD40L interactions occur specifically between T cells and antigen-loaded dendritic cells; and a later, non-cognate stage during which these interactions no longer require prior engagement of the T-cell receptor. Therefore, LIPSTIC enables the direct measurement of dynamic cell-cell interactions both in vitro and in vivo. Given its flexibility for use with different receptor-ligand pairs and a range of detectable labels, we expect that this approach will be of use to any field of biology requiring quantification of intercellular communication.
