Analysis of Lymphocyte Extravasation Using an In Vitro Model of the Human Blood-brain Barrier

Area of Science:

• Neuroimmunology
• Cell Biology
• Biomedical Engineering

Background:

• Lymphocyte extravasation into the central nervous system (CNS) is crucial for immune surveillance but can be altered in disease.
• Understanding lymphocyte migration into the CNS is vital for diagnosing and treating inflammatory CNS conditions.

Purpose of the Study:

• To develop and validate an in vitro model of the human blood-brain barrier (BBB) for studying lymphocyte extravasation.
• To enable the investigation of rare lymphocyte subsets and the impact of various factors on CNS immune cell trafficking.

Main Methods:

• An in vitro model using human brain microvascular endothelial cells (HBMEC) cultured on transwell inserts to simulate the BBB endothelium.
• Validation of barrier integrity through immunohistochemistry for zonula occludens, transendothelial electrical resistance (TEER) measurements, and Evans blue permeation assays.
• Application of the model to study the diapedesis of specific lymphocyte subsets, including NK cells, and the effects of cellular interactions, cytokines, chemokines, and therapeutic interventions.

Main Results:

• The developed in vitro model successfully mimics the human BBB.
• The model allows for the detailed analysis of lymphocyte extravasation, including rare subsets like CD56brightCD16dim/- NK cells.
• The system is capable of assessing the influence of inflammatory stimuli and treatments on both lymphocyte migration and endothelial barrier function.

Conclusions:

• The established in vitro BBB model provides a valuable tool for studying lymphocyte trafficking in the CNS.
• This model facilitates research into the mechanisms of inflammatory CNS diseases and the evaluation of potential therapeutic strategies.
• The model's versatility allows for comprehensive analysis of factors influencing immune cell entry into the CNS and BBB integrity.