FIG. 6.

(A) Adhesion of pilE::ermC and Δopc::cat mutants with NIID280 (ST-2032) and H44/76 (ST-32) genetic backgrounds to HBMEC. Mean CFU of adherent bacteria per 10⁴ cells of HBMEC in at least three experiments are shown, and error bars represent the standard errors of the means. *, P < 0.01; **, P < 0.05; ***, P < 0.06; and #, P > 0.1 (compared to the isogenic wild-type strain). (B) Western blotting for LptA, PilC, Opc, Opa, and pilin proteins. Bacterial extracts equivalent to an OD₆₀₀ of 0.05 (for LptA and PilC), 0.01 (for Opc and Opa), or 0.0025 (for pilin) were analyzed by Western blotting. Lane 1, HT1125 (ST-2032 wild type); lane 2, HT1222 (ST-2032 ΔlptA); lane 3, HT1034 (ST-32 wild type); lane 4, HT1243 (ST-32 ΔlptA). The pilC1 mutant (HT1178, lane 5), the pilC2 mutant (HT1182, lane 6), and the double mutant (HT1186, lane 7) were used only as controls for anti-PilC rabbit serum. (C) Transmission electron micrographs showing piliation of meningococcal strain HT1125 and the ΔlptA mutant HT1222 and of meningococcal strain HT1034 and the ΔlptA mutant HT1243. Bars, 200 nm.