Fig 2: The role of B cells in B. burgdorferi control.(A) Schematic representation of the experimental strategy. B cells were depleted with a human CD20-specific antibody (a-CD20) injected 2 days before (d-2), at the day of infection (d0) and 4 and 7 days after infection with B. burgdorferi. PBS injection served as a control. (B) Shown is the percentage (mean +/- SEM) of human B cells (CD19+) among human leukocytes (CD45+) in the peripheral blood of humanized mice injected with PBS or a CD20-specific antibody in the absence (not infected) or presence (infected) of an infection with B. burgdorferi. Shown is one representative out of two independent experiments with six mice per group. (C–F) Depicted are the serum IgM levels (C), the B. burgdorferi- (D), glucose 6-phosphate isomerase (GPI)- (E), and double-stranded DNA (dsDNA)-specific (F) IgM responses (mean+/-SEM) in infected humanized mice treated with PBS or a CD20-specific antibody as determined by ELISA. Shown is one out of two independent experiments with n = 6 mice per group. A two-way Anova with Tukey’s or Sidak’s multiple comparison test was used for statistical evaluation. *p<0.05, **p<0.01, ns = not significant. (G) Shown is the joint thickness (mean+/-SEM) of the right and left hind ankle joint of humanized mice infected with B. burgdorferi and treated with PBS or a CD20-specific antibody (anti-CD20) during the first 7 days. A two-way Anova with Tukey’s multiple comparison test was used for statistical evaluation. n = 6–10 mice per group. *p<0.05. Shown is one representative out of three independent experiments.