Fig. 1From: TNF-α Opens a Paracellular Route for HIV-1 Invasion across the Blood-Brain Barrier Blood-brain-barrier model (A) Design of the bilayer model with brain neural microvascular endothelial cells (BMVEC), fibronectin or collagen I-fibronectin matrix, membrane, and astrocytes. (B, C) Transmission electron microscopy of a vertical cross section across the endothelial layer showing cells in close apposition (×3000 and ×6800, respectively). (D) Fusion of cell membranes between adjoining cells resembling zonula adhaerens (×22,000).Back to article page