An In Vitro Model for Studying Pathogen Crossing of the Blood-Brain Barrier and Brain Cell Infection

Take an in vitro blood-brain barrier, or BBB, model comprising two compartments separated by a porous membrane.

The upper or luminal compartment contains microvascular endothelial cells. These cells express tight junctions, mimicking the blood-brain barrier endothelium that limits the passage of cells and molecules.          

The lower or abluminal compartment contains neurons, astrocytes, and microglia, representing the brain parenchyma.

Introduce a neurotropic virus into the luminal compartment to simulate a blood-borne infection and incubate.

The virus is endocytosed by the endothelial cells, undergoes intracellular trafficking within vesicles, and is released on the abluminal side.

Post-incubation, remove the upper chamber. Sample the medium from the abluminal side to assess the viral quantity, confirming the successful crossing of the endothelial layer.

Add fresh medium and incubate again.           

The virus enters the neural cells via endocytosis, replicates, and releases viral progeny.

Quantify the increased extracellular viral load to confirm viral neuroinvasion and replication.