B/dbpAB + Cef2 + aT dbpAB + Cef2 + aT wk 6 0/2 4/4 3/4 0/8 0/8 0/8 0/8 wk 9 0/2 4/4 3/4 0/8 0/8 0/8 0/8 Ear 0/2 4/4 3/4 0/8 0/8 0/8 0/8 Culture

B/dbpAB + Cef2 + aT dbpAB + Cef2 + aT wk 6 0/2 4/4 3/4 0/8 0/8 0/8 0/8 wk 9 0/2 4/4 3/4 0/8 0/8 0/8 0/8 Ear 0/2 4/4 3/4 0/8 0/8 0/8 0/8 Culture at 15 wk Bladder 0/2 4/4 3/4 0/8 0/8 0/8 0/8 Joint 0/2 4/4 3/4 0/8 0/8 0/8 0/doi:10.1371/journal.pone.0121512.tPLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,8 /DbpA and B Promote Arthritis and Post-Treatment Persistence in MiceFig 3. IgG antibody levels in mouse serum samples. Antibody levels were measured using enzyme immunoassays with whole B. burgdorferi lysate as antigen. In panel A, the results are from Experiment II, in panel B from Experiment IV, and in panels C and D combined from Experiments II and III. The results in each panel are obtained from an individual analysis. Each symbol represents the result of one animal. Results are expressed as OD492 values and all samples were analysed in duplicate. The line indicates the mean of each group. Groups with the same letter do not differ at 5 level of probability (Tukey’s HSD test, panels A and B). * P 0.05, *** P 0.001. doi:10.1371/journal.pone.0121512.gsusceptibility testing indicated that both strains were equally susceptible to ceftriaxone with MIC of 0.064 g/ml. B. burgdorferi cultures of ear biopsy samples taken at 6 and 9 weeks of infection were negative in dbpAB/dbpAB and dbpAB infected mice suggesting clearance of spirochetemia (Table 2, groups 9 and 10). In parallel, the post mortem B. burgdorferi cultures of ear, bladder and joint tissues did not show growth, and, importantly, there was no measurable swelling in the tibiotarsal joints of the treated animals (Fig. 2B, groups 9 and 10). Immunosuppression of the mice with anti-TNF-alpha treatment (once a week during weeks 7 to 10) did not have any ABT-737 web effect on the culture results or on the arthritis development (Table 2 and Fig. 2B, groups 11 and 12).PLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,9 /DbpA and B Promote Arthritis and Post-Treatment Persistence in MiceTable 3. B. burgdorferi PCR results of Experiment II at 15 weeks of infection. flaB Group 6 7 8 9 10 11 12 Strain/treatment Uninfected dbpAB/dbpAB dbpAB dbpAB/dbpAB + Cef2 dbpAB + Cef2 dbpAB/dbpAB + Cef2 + aT dbpAB + Cef2 + aT Ear 0/2 3/4 0/4 0/8 0/8 0/8 0/8 Bladder 0/2 1/3a 0/4 0/8 0/8 0/8 0/8 Joint 0/2 4/4 2/4 5/8 0/8 8/8 0/8 Ear 0/2 2/4 1/4 0/8 0/8 0/8 0/8 ospA Bladder 0/2 4/4 0/4 0/8 0/8 0/8 0/8 Joint 0/2 4/4 3/4 8/8 0/8 8/8 0/a One sample not available for flaB PCR doi:10.1371/journal.pone.0121512.tFig 4. Bacterial load in joint samples. A 102 base pair fragment of ospA gene was amplified from the joint DNA samples. The minimal sensitivity of PCR was 40 bacterial cells. The results are expressed as the number of bacteria PX-478 site genomes per 100 ng of extracted DNA. Each symbol represents an individual animal and the samples were analysed in triplicate. In Experiment II, one joint sample of dbpAB infected mice was qPCR negative at 15 weeks of infection, in Experiment III five joint samples of dbpAB infected animals were qPCR negative at two weeks, and in Experiment IV three joint samples of dbpAB infected and ceftriaxone treated (at six weeks of infection) mice were qPCR negative at 15 weeks. The line indicates the median of positive results in each group. “Cef” Ceftriaxone treatment, “aT” anti-TNF-alpha treatment. ** P 0.01 doi:10.1371/journal.pone.0121512.gPLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,10 /DbpA and B Promote Arthritis and Post-Treatment Persistence in MiceTaken together, the above results.B/dbpAB + Cef2 + aT dbpAB + Cef2 + aT wk 6 0/2 4/4 3/4 0/8 0/8 0/8 0/8 wk 9 0/2 4/4 3/4 0/8 0/8 0/8 0/8 Ear 0/2 4/4 3/4 0/8 0/8 0/8 0/8 Culture at 15 wk Bladder 0/2 4/4 3/4 0/8 0/8 0/8 0/8 Joint 0/2 4/4 3/4 0/8 0/8 0/8 0/doi:10.1371/journal.pone.0121512.tPLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,8 /DbpA and B Promote Arthritis and Post-Treatment Persistence in MiceFig 3. IgG antibody levels in mouse serum samples. Antibody levels were measured using enzyme immunoassays with whole B. burgdorferi lysate as antigen. In panel A, the results are from Experiment II, in panel B from Experiment IV, and in panels C and D combined from Experiments II and III. The results in each panel are obtained from an individual analysis. Each symbol represents the result of one animal. Results are expressed as OD492 values and all samples were analysed in duplicate. The line indicates the mean of each group. Groups with the same letter do not differ at 5 level of probability (Tukey’s HSD test, panels A and B). * P 0.05, *** P 0.001. doi:10.1371/journal.pone.0121512.gsusceptibility testing indicated that both strains were equally susceptible to ceftriaxone with MIC of 0.064 g/ml. B. burgdorferi cultures of ear biopsy samples taken at 6 and 9 weeks of infection were negative in dbpAB/dbpAB and dbpAB infected mice suggesting clearance of spirochetemia (Table 2, groups 9 and 10). In parallel, the post mortem B. burgdorferi cultures of ear, bladder and joint tissues did not show growth, and, importantly, there was no measurable swelling in the tibiotarsal joints of the treated animals (Fig. 2B, groups 9 and 10). Immunosuppression of the mice with anti-TNF-alpha treatment (once a week during weeks 7 to 10) did not have any effect on the culture results or on the arthritis development (Table 2 and Fig. 2B, groups 11 and 12).PLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,9 /DbpA and B Promote Arthritis and Post-Treatment Persistence in MiceTable 3. B. burgdorferi PCR results of Experiment II at 15 weeks of infection. flaB Group 6 7 8 9 10 11 12 Strain/treatment Uninfected dbpAB/dbpAB dbpAB dbpAB/dbpAB + Cef2 dbpAB + Cef2 dbpAB/dbpAB + Cef2 + aT dbpAB + Cef2 + aT Ear 0/2 3/4 0/4 0/8 0/8 0/8 0/8 Bladder 0/2 1/3a 0/4 0/8 0/8 0/8 0/8 Joint 0/2 4/4 2/4 5/8 0/8 8/8 0/8 Ear 0/2 2/4 1/4 0/8 0/8 0/8 0/8 ospA Bladder 0/2 4/4 0/4 0/8 0/8 0/8 0/8 Joint 0/2 4/4 3/4 8/8 0/8 8/8 0/a One sample not available for flaB PCR doi:10.1371/journal.pone.0121512.tFig 4. Bacterial load in joint samples. A 102 base pair fragment of ospA gene was amplified from the joint DNA samples. The minimal sensitivity of PCR was 40 bacterial cells. The results are expressed as the number of bacteria genomes per 100 ng of extracted DNA. Each symbol represents an individual animal and the samples were analysed in triplicate. In Experiment II, one joint sample of dbpAB infected mice was qPCR negative at 15 weeks of infection, in Experiment III five joint samples of dbpAB infected animals were qPCR negative at two weeks, and in Experiment IV three joint samples of dbpAB infected and ceftriaxone treated (at six weeks of infection) mice were qPCR negative at 15 weeks. The line indicates the median of positive results in each group. “Cef” Ceftriaxone treatment, “aT” anti-TNF-alpha treatment. ** P 0.01 doi:10.1371/journal.pone.0121512.gPLOS ONE | DOI:10.1371/journal.pone.0121512 March 27,10 /DbpA and B Promote Arthritis and Post-Treatment Persistence in MiceTaken together, the above results.