FIG 1.

Carrier isolates and strain 8013/clone12 are less invasive than meningococcal disease isolates in epithelial host cells. Adhesion to and invasion of N. meningitidis into Detroit 562 and NP69 cells were assessed over a 6 h infection period. (A and B) Adherence to (A) and invasion of (B) both cell lines of serogroup B strain MC58 (■) and unencapsulated strain MC58 siaD (□) were determined by gentamicin protection assays at the time intervals indicated. Both cell lines were infected at an MOI of 30. (C and D) Adherence to (C) and invasion of (D) serogroup C disease isolate N. meningitidis 8013/clone12 and two serogroup B carrier isolates α711 and α4 (MOI 30) were determined by gentamicin protection assays at 6 h p.i. and are represented as relative data compared to MC58. The data show mean values ± the standard deviation (SD) of three independent experiments conducted in duplicate. *, P < 0.05.