Rat murine chimeric TNF-alpha antibody of IgG2ak isotype (Centocor, Malvern, PA, USA) was administered once a week 10 mg/kg intraperitoneally for four weeks. The development of joint manifestations was monitored as described above. The mice were killed at 15 weeks of infection. Tissue samples from ear, bladder and hind tibiotarsal joint were collected for culture and PCR analyses. Blood was collected for serology, and one tibiotarsal joint for histology. In experiment III, eight dbpAB/dbpAB (group 14), eight dbpAB (group 15) ABT-737 mechanism of action infected animals, and four uninfected control (group 13) animals were killed at two weeks of infection. Samples from ear, bladder and hind tibiotarsal joint were collected for culture. One hind tibiotarsal joint was collected for PCR analysis of B. burgdorferi tissue load, and blood was collected for serology. In experiment IV, eight animals we infected with dbpAB/dbpAB (groups 17 and 19) and eight animals with dbpAB (groups 18 and 20). Four uninfected animals (group 16) were negative controls. Eight animals (groups 19 and 20) were treated with ceftriaxone at six weeks. The development of joint manifestations was monitored as explained above. The mice were killed at 15 weeks of infection. Tissue samples from ear, bladder and hind tibiotarsal joint were collected for culture and PCR analyses. Blood was collected for serology.PLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,3 /DbpA and B Promote Arthritis and Post-Treatment Persistence in MiceFig 1. Design of the mouse experiments. In Experiment I, four dbpAB/dbpAB (group 2), eight dbpAB/ dbpA (group 3), eight dbpAB/dbpB (group 4), two dbpAB (group 5) infected animals and two uninfected control animals (group 1) were killed at seven weeks of infection. In Experiment II, 16 infected animals (groups 4 and 5) were treated with ceftriaxone and 16 (groups 6 and 7) with ceftriaxone and anti-TNF-alpha. The ceftriaxone treatment was started at two weeks (25 mg/kg twice a day for 5 days) and the anti-TNF-alpha treatment at seven weeks of infection (10 mg/kg once a week for 4 weeks). Ear biopsy samples were collected at 6 and 9 weeks of infection to monitor the dissemination of the infection. In Experiment III, mice were killed at two weeks to study infection kinetics and bacterial load in joints. In Experiment IV, eight infected animals were treated with ceftriaxone at six weeks of infection (groups 14 and 15). doi:10.1371/journal.pone.0121512.gPreparation and B. burgdorferi culture of tissue samplesIn experiments II, the infection status of the mice was assessed by culturing ear biopsy samples at 6 and 9 weeks of infection. Ear, bladder and hind tibiotarsal joint samples were collected at seven weeks (experiments I), at 15 weeks (experiments II and IV), or at 2 weeks (experiment III) of the infection. All instruments were Grazoprevir price disinfected in ethanol between the dissections of the different samples. The tissue samples were grown in BSK II medium supplemented withPLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,4 /DbpA and B Promote Arthritis and Post-Treatment Persistence in Micephosphomycin (50 g/ml; Sigma-Aldrich) and rifampin (100 g/ml; Sigma-Aldrich) at 33 for a maximum of 6 weeks.DNA extraction and PCR analysisEar, bladder and joint tissue samples were stored at -20 before the DNA extraction. Tissue samples were incubated with proteinase-K (275 g/ml, Promega, Madison, WI, USA) at 56 for overnight before the DNA was extracted using NucliSENS easyMAG kit (Biom ieux, M.Rat murine chimeric TNF-alpha antibody of IgG2ak isotype (Centocor, Malvern, PA, USA) was administered once a week 10 mg/kg intraperitoneally for four weeks. The development of joint manifestations was monitored as described above. The mice were killed at 15 weeks of infection. Tissue samples from ear, bladder and hind tibiotarsal joint were collected for culture and PCR analyses. Blood was collected for serology, and one tibiotarsal joint for histology. In experiment III, eight dbpAB/dbpAB (group 14), eight dbpAB (group 15) infected animals, and four uninfected control (group 13) animals were killed at two weeks of infection. Samples from ear, bladder and hind tibiotarsal joint were collected for culture. One hind tibiotarsal joint was collected for PCR analysis of B. burgdorferi tissue load, and blood was collected for serology. In experiment IV, eight animals we infected with dbpAB/dbpAB (groups 17 and 19) and eight animals with dbpAB (groups 18 and 20). Four uninfected animals (group 16) were negative controls. Eight animals (groups 19 and 20) were treated with ceftriaxone at six weeks. The development of joint manifestations was monitored as explained above. The mice were killed at 15 weeks of infection. Tissue samples from ear, bladder and hind tibiotarsal joint were collected for culture and PCR analyses. Blood was collected for serology.PLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,3 /DbpA and B Promote Arthritis and Post-Treatment Persistence in MiceFig 1. Design of the mouse experiments. In Experiment I, four dbpAB/dbpAB (group 2), eight dbpAB/ dbpA (group 3), eight dbpAB/dbpB (group 4), two dbpAB (group 5) infected animals and two uninfected control animals (group 1) were killed at seven weeks of infection. In Experiment II, 16 infected animals (groups 4 and 5) were treated with ceftriaxone and 16 (groups 6 and 7) with ceftriaxone and anti-TNF-alpha. The ceftriaxone treatment was started at two weeks (25 mg/kg twice a day for 5 days) and the anti-TNF-alpha treatment at seven weeks of infection (10 mg/kg once a week for 4 weeks). Ear biopsy samples were collected at 6 and 9 weeks of infection to monitor the dissemination of the infection. In Experiment III, mice were killed at two weeks to study infection kinetics and bacterial load in joints. In Experiment IV, eight infected animals were treated with ceftriaxone at six weeks of infection (groups 14 and 15). doi:10.1371/journal.pone.0121512.gPreparation and B. burgdorferi culture of tissue samplesIn experiments II, the infection status of the mice was assessed by culturing ear biopsy samples at 6 and 9 weeks of infection. Ear, bladder and hind tibiotarsal joint samples were collected at seven weeks (experiments I), at 15 weeks (experiments II and IV), or at 2 weeks (experiment III) of the infection. All instruments were disinfected in ethanol between the dissections of the different samples. The tissue samples were grown in BSK II medium supplemented withPLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,4 /DbpA and B Promote Arthritis and Post-Treatment Persistence in Micephosphomycin (50 g/ml; Sigma-Aldrich) and rifampin (100 g/ml; Sigma-Aldrich) at 33 for a maximum of 6 weeks.DNA extraction and PCR analysisEar, bladder and joint tissue samples were stored at -20 before the DNA extraction. Tissue samples were incubated with proteinase-K (275 g/ml, Promega, Madison, WI, USA) at 56 for overnight before the DNA was extracted using NucliSENS easyMAG kit (Biom ieux, M.