The intensity of immunostaining for the blood-brain barrier protein, PgP was significantly increased in endothelial monolayers co-cultured with astrocytes for 5 days (A; panel C) compared to monolayers cultured alone (A; panel A), represented graphically in B; P=0.0010; n=3 independent experiments). P-glycoprotein expression was not significantly altered in monolayers co-cultured with MoDC for 5 days (A; panel B) compared to monolayers cultured alone (A; panel A), represented graphically in B; P=0.254; n=3 independent experiments). Values obtained without the primary antibody have been subtracted in B. *P <0.05, **P<0.01, ***P<0.001.