Differential immune cell dynamics in the CNS cause CD4+ T cell compartmentalization

Area of Science:

• Neuroimmunology
• Cellular Neuroscience

Background:

• Autoimmune central nervous system (CNS) inflammation involves perivascular lymphocyte cuffs, but their formation mechanisms remain unclear.
• Previous assumptions suggested limited lymphocyte motility in the CNS contributes to these structures.

Purpose of the Study:

• To investigate the dynamic nature of perivascular immune cells in the CNS during autoimmune inflammation.
• To elucidate the role of CXCR4 in regulating lymphocyte motility and perivascular cuff formation.

Main Methods:

• Intravital two-photon imaging of the brain in mice with experimental autoimmune encephalomyelitis.
• In vivo interference with CXCR4 signaling.

Main Results:

• Perivascular immune cells exhibit highly dynamic motility, refuting static cuff formation theories.
• Vessel-associated lymphocyte motility is actively promoted and can be inhibited by CXCR4 antagonism.
• CXCR4 antagonism disrupted dynamic vessel cuffs and led to tissue invasion.
• CXCR4-mediated motility was prominent in CD4(+) T cells along CNS vessels, unlike CD8(+) T cells.

Conclusions:

• Lymphocyte accumulation in perivascular cuffs is a dynamic process regulated by active motility.
• CXCR4 plays a critical role in mediating CD4(+) T cell motility within the CNS vasculature.
• Understanding this differential compartmentalization is key to comprehending CNS autoimmune diseases.