, 1989) and for recombinant protein expression as described previously (Jamet et al., 2009). Human umbilical vein endothelial cells (HUVECs) (promoCell) were grown in Endo-SFM supplemented with 10% heat-inactivated foetal calf serum (FCS),

heparin (0.5 IU mL−1) and endothelial cell growth supplement (1.25 μg mL−1) (Sigma) overnight at 37 °C in a humidified incubator under 5% CO2. HEC-1B is a human endometrial adenocarcinoma selleck screening library cell line and was grown in Dulbecco’s modified Eagle’s medium with Glutamax (Life Technologies) supplemented with 10% heat-inactivated FCS for 2–3 days. Cell monolayers were infected as described previously (Jamet et al., 2009). Adherent bacteria were harvested at various time points. Mutants disrupted for NMA1805 and NMA1806 were constructed by gene

replacement. The 5′ and 3′ ends of the NMA1805 gene were PCR amplified from N. meningitidis using pairs of primers NMA1805-Up-Sac/NMA1805-Up-Bam and NMA1805-Down-Bam/NMA1805-Down, respectively (Table 1). The 5′ and 3′ ends of the NMA1806 gene were PCR amplified using pairs of primers NMA1806-Up-Sac/NMA1806-Up-Bam and NMA1806-Down-Bam/NMA1806-Down, respectively (Table 1). The PCR products were cloned into TOPO cloning vector (Invitrogen). A chloramphenicol-resistance cassette or a kanamycin-resistance cassette was then inserted as a BamHI DNA fragment. The linearized resulting plasmids were transformed into N. meningitidis, as described Natural Product Library cell assay previously (Pelicic et al., 2000). The transformants were selected in the presence of kanamycin and chloramphenicol. The allele exchange was confirmed by DNA sequencing (data not shown). To complement the 8013NMA1803 mutant, the wild-type NMA1803 gene was amplified using primers NMA1803cF and NMA1803cR, Oxymatrine which contained overhangs with restriction sites for PacI (Table 1). This PCR fragment was restricted with PacI and cloned into PacI-cut pGCC4 vector, adjacent to lacIOP regulatory sequences (Mehr et al., 2000). This placed NMA1803 under the transcriptional control of an isopropyl-β-d-thiogalactopyranoside-inducible

promoter within a DNA fragment corresponding to an intragenic region of the gonococcal chromosome conserved in N. meningitidis. The NMA1803ind allele was then introduced into the chromosome of an 8013NMA1803 mutant by homologous recombination. Total RNA isolation and real-time RT-PCR were performed as described previously (Morelle et al., 2003; Yasukawa et al., 2006). The aphA3 gene, which encodes the kanamycin resistance or the NMA0159 gene, which was shown not to be differentially expressed upon contact with host cells, was used as an internal reference. The β-galactosidase activity was measured as described previously (Miller, 1972), from bacteria grown in an infection medium and harvested after 1 and 4 h of adhesion to HUVECs. Briefly, the number of CFUs of cell-associated bacteria and of bacteria grown in infection medium was determined by plating serial dilutions on GCB plates.