<i>B. burgdorferi</i> infection in WT, tPA −/− and PAI-1 −/− mice.

Note. C57BL/6 WT, tPA and PAI-1 knock-out mice (6–8 per group) were inoculated with B. burgdorferi strain B31 or sham and sacrificed two weeks later. #Plasminogen activator (PA) activity was measured in citrate plasma using amidolytic assays and expressed as a percentage. ##B. burgdorferi numbers were determined by quantitative PCR and expressed as described in Figures 2 and 3. $In addition, an in vitro phagocytosis assay was performed using naive mice (n = 6–8 per group) as described in Figure 2. Whole blood was incubated with viable CFSE-labeled B. burgdorferi for 60 minutes at 37 or 4°C as a control and phagocytosis was depicted as the phagocytosis index as described in Figure 2. a,cPA activity was significantly lower in tPA knock-out mice compared to WT controls, regardless whether mice were inoculated with B. burgdorferi or sham, p<0,0001. b,dPA activity was significantly higher in PAI-1 knock-out mice compared to WT controls, regardless whether mice were inoculated with B. burgdorferi or sham, p<0,0001. Results represent the mean±SEM. Non-parametric statistical tests were used to analyze the differences between the groups. A p-value<0,05 was considered statistically significant.