After three washes with phosphate-buffered saline (PBS) (supplemented

with.15 M NaCl, 0.03 M phosphate, 0.02% sodium azide, pH 7.2), 0.05% Tween 20. The proteins bound to the cells were eluted by incubation with 0.1 M glycine-HCl, pH 2.0, for 15 min. Cells were removed by centrifugation at 14,000 × g for 20 min at 4°C, and supernatants were then analysed by Western blotting. Protease degradation assay To characterize protease-susceptibility of CFH and FHL-1 binding proteins of B. garinii ST4 PBi, cells were treated with two different proteases as described previously [34]. Briefly, spirochetes were grown to mid-log phase, sedimented by centrifugation at 5,000 × g for 30 min, washed twice with cold PBS containing 5 mM MgCl2 (PBS-Mg), and resuspended in 100 μl PBS-Mg. To the Borrelia cell suspension (at a concentration of 108 in a final volume of 0.5 ml), proteinase K

or trypsin selleckchem was added to a final concentration of 12,5 μg/ml to 100 μg/ml. Following incubation for 1 hour at room temperature, proteolytic degradation with proteinase K or trypsin was terminated by the SCH727965 addition of 5 μl of phenylmethylsulfonyl fluoride or by the addition of 5 μl of phenylmethylsulfonyl fluoride and 5 μl of 4-(2-aminoethyl)-benzenesulfonyl fluoride, respectively. Borrelia were then gently washed twice with PBS-Mg, resuspended in 20 μl PBS-Mg, and lysed by sonication five times using a Branson B-12 sonifier (Heinemann, Schwäbisch Gmünd, Germany). Equal volumes of Borrelia lysates were subjected to Tris/Tricine SDS-PAGE, and proteins were transferred to nitrocellulose membranes as described previously [16]. Susceptibility of proteins to proteolytic degradation was assessed by Western or ligand affinity blotting with the appropriate monoclonal or polyclonal antibodies, learn more followed by incubation with a horseradish peroxidase-conjugated IgG antibody, and then visualized by the addition of 3, 3′, 5, 5′-tetramethylbenzidine.

PCR cloning, expression and purification of recombinant CspA orthologous proteins Sequences of genes encoding for CspA B31 and orthologs from B. garinii ST4 PBi were obtained from genbank (NC_006129 and NC_001857). Primers were designed using primer3 (MIT) and listed in table 2. Amplification reactions were performed in a 50 μl final volume, containing 25 μl IQ Supermix (Bio-Rad, Veenendaal, The Netherlands), 15 pmol forward primer, 15 pmol reverse primer, and 10 μl of a DNA isolate of cultured B31 or PBi. Following an enzyme activation step for 3 min at 95°C, amplification comprised 50 cycles of 30 s at 95°C, 30 s at 55°C and 30 s at 72°C. Genes lacking their leader sequences were ligated in frame into the pGEX-5X3 vector (Amersham Bioscience, Freiburg, Germany). The ligation mixtures were used to transform Escherichia coli MC1061.