on monocyte transmigration through human choroid plexus papilloma cells (HIBCPP). HIBCPP were infected with N. meningitidis MC58 wild-type, its unencapsulated mutant MC58ΔsiaD or with the apathogenic strain α14 (multiplicity of infection = 10) for 2 h, or stimulated with TNFα (10 ng/ml) as described in Materials and methods. PMNs were applied 24 h after stimulation onto the basolateral side of the inverted HIBCPP culture (monocyte:HIBCPP ratio of 1:1). During the experiment the effect on barrier function of the HIBCPP layer was determined by transepithelial electrical resistance (TEER) (A) and dextran TexasRed flux (B). TEER values were measured before stimulation, 24 h thereafter and 4 hours after the monocyte TM period (A) (n = 5 in triplicate). Dextran TexasRed flux was measured in the basolateral-to-apical direction after the TM period of 4 h (B) (n = 5 in triplicate). In this experimental setting, monocyte chemoattractant protein (MCP) -1 (50 ng/ml) was used as chemoattranctant for the 2’,7’-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF)-labeled monocytes, which were applied to the basolateral side of the inverted transwell HIBCPP culture. The percentage of transmigrated monocytes was measured fluorometrically after 4 h of TM (n = 5 in triplicate). **
P <0.01 compared to corresponding control HIBCPP.