Visualization of cell-cell interaction contacts-synapses and kinapses.

Area of Science:

• Immunology
• Cell Biology
• Biophysics

Background:

• T-cell activation depends on T-cell antigen receptor (TCR) and peptide-MHC interactions at the T-cell/APC interface.
• Immunological synapses, characterized by supramolecular activation clusters (SMACs), stabilize T-cell-APC interactions and facilitate directed secretion.
• Existing models of SMACs are re-evaluated as higher-order membrane-cytoskeleton domains analogous to those in amoeboid locomotion.

Purpose of the Study:

• To introduce the concept of a 'kinapse' (moving junction) to describe adhesive junctions formed during T-cell locomotion over APCs.
• To differentiate the roles of synapses and kinapses in distinct stages of T-cell priming.
• To highlight the challenges in visualizing these dynamic cellular structures in vitro and in vivo.

Main Methods:

• Conceptual framework development based on existing literature and cell motility models.
• Comparative analysis of immunological synapses and kinapses in T-cell function.
• Discussion of in vitro and in vivo visualization techniques and their limitations.

Main Results:

• Proposed that SMACs function similarly to membrane-cytoskeleton zones in cell locomotion.
• Defined kinapses as dynamic, moving junctions crucial for T-cell signaling during locomotion.
• Highlighted that both synapses and kinapses are essential for optimal T-cell effector functions through cyclical engagement.

Conclusions:

• T-cell-APC interactions are mediated by both stable synapses and dynamic kinapses.
• The cyclical interplay between synapses and kinapses is vital for effective T-cell priming and function.
• Further research is needed to overcome visualization challenges for these dynamic structures.