Dynamic Mitochondrial Migratory Features Associated with Calcium Responses during T Cell Antigen Recognition.

Area of Science:

• Immunology
• Cell Biology
• Systems Biology

Background:

• T cell receptors (TCRs) recognize peptide-MHC complexes with high specificity.
• The link between TCR structural recognition and distinct T cell effector functions is not fully understood.
• Mitochondrial dynamics and calcium signaling are implicated in T cell activation.

Purpose of the Study:

• To investigate the role of mitochondrial positioning and calcium responses in T cell antigen recognition.
• To develop a quantitative method for analyzing T cell signaling and organelle dynamics.
• To understand how antigen potency influences T cell responses at the single-cell level.

Main Methods:

• Engineered a microfluidic system for synchronized cell-cell pairing and real-time imaging.
• Developed image-derived metrics to quantify calcium responses and mitochondria movement.
• Utilized altered peptide ligands and a T cell hybridoma line from experimental autoimmune encephalomyelitis models.
• Applied partial least squares regression to model T cell responses.

Main Results:

• Antigen potency modulates calcium response at the single-cell level.
• Mitochondrial positioning is a strong predictor of calcium response in T cells.
• T cell mitochondria exhibit rapid directional changes upon antigen exposure, moving away from the immunological synapse.
• Quantification of mitochondria movement as a dynamic process reconciles conflicting prior reports.

Conclusions:

• Mitochondrial positioning and calcium signaling are critical for T cell antigen recognition.
• The developed methodology provides a powerful tool for studying immune cell interactions.
• This approach can be extended to investigate other immune cell types and signaling phenomena.