Linking morphodynamics and directional persistence of T lymphocyte migration

Area of Science:

• Immunology
• Cell Biology
• Biophysics

Background:

• T cells are critical for adaptive immunity and require directed migration to antigen-presenting sites.
• T lymphocytes exhibit amoeboid movement, similar to neutrophils, with distinct F-actin and myosin II distribution.
• Understanding T cell migration dynamics is key to immune response and homing mechanisms.

Purpose of the Study:

• To investigate the mechanisms of T cell migration and reorientation.
• To analyze the role of membrane protrusion dynamics in T cell movement.
• To develop a model explaining T cell migration behaviors.

Main Methods:

• Total internal reflection fluorescence (TIRF) microscopy was used to observe T cell interactions.
• Analysis focused on cell contact areas with ICAM-1 and CXCL12/SDF-1.
• Quantitative analysis of protrusion bifurcation and cell turning events was performed.

Main Results:

• T cell migration and turning are mediated by bifurcation and lateral separation of membrane protrusions.
• A pivot mechanism involving protrusion cessation was identified for cell reorientation.
• Bifurcation frequency distribution suggests a spontaneous process, with waiting times influenced by pivot-side persistence.
• Protrusion switching correlates with persistent migration, while lack of switching is linked to cell turning.

Conclusions:

• T cell migration involves a complex interplay of protrusion dynamics and a pivot-based turning mechanism.
• The study provides insights into the stochastic nature of T cell movement and its regulation.
• A spatio-temporal stochastic model of F-actin dynamics is proposed to explain observed migration behaviors.