Figure 6

Immunohistochemical characterization of the cellular extravasates. Anti-human CD8 antibody was used to identify TALL-104 cells within the cellular extravasates. A-D) Negligible amounts of CD8 positive cells were detected in the perivascular space when BBB was not breached (see also Figures 2 and 4). Arrowheads in B and H show examples of the rare extravasated cells. (E-G) Note that CD8 immunoreactivity was mostly confined in the intravascular space. I-P) Brain sections obtained from successful BBBD procedures display elevated anti-CD8 immunoreactivity in correspondence of perivascular aggregates of cells (arrowheads). See also Figure 3 and 5.