FIG. 5.

Protease pretreatment eliminates the association of serotype 1 with brain microvascular endothelial cells. (A) Distribution of radioactivity in the three compartments (upper, monolayer, and lower) of large (12-mm) transwell chambers with BMEC barriers inoculated with serotype 1, shown as mean of n = 3 replicates. The mean (SD) percentage of radioactivity associated with the BMEC monolayer was 16 (8.7), 14 (5.3), and 30 (1.8) after 3, 7, and 24 h of incubation, respectively. (B) The effects of pretreating the BMEC monolayer with proteinase K are shown, illustrating that pretreatment completely eliminated the association with serotype 1 even after 24 h of incubation.