Figure 1

Effects of N. meningitidis on polymorphonuclear neutrophil (PMN) transmigration (TM) 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 Material and methods. PMNs were applied 24 h after stimulation onto the basolateral side of the inverted HIBCPP culture (PMN:HIBCPP ratio of 10:1). 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 h after the PMN TM period (A) (n = 9 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 IL-8 (10 ng/ml) was used as chemoattractant, which was applied to the basolateral side of the inverted transwell HIBCPP culture. The percentage of transmigrated PMNs was measured fluorometrically after 4 h of TM (n = 3 in triplicate). ^** P <0.01 compared to corresponding control HIBCPP.