Figure 5

Phagocytosis of B. burgdorferi and inflammation in vivo during early infection are similar between MBL deficient mice and WT control. (A) Phagocytosis of B. burgdorferi by murine neutrophils in whole blood. Whole blood samples from five mice were subjected to FACS analysis after 5, 15 and 30 min of incubation at 37 °C with CFSE-labeled viable B. burgdorferi N40. Neutrophils were gated using rat-anti mouse Ly6 antibodies and the phagocytosis was calculated by the mean fluorescence x percentage of positive neutrophils (phagocytosis index). Samples kept on ice were used as baseline. (B) A second phagocytosis experiment was also performed with macrophages collected from peritoneal fluid from WT mice. Macrophages (50.000 per sample) were incubated with 10% WT serum or MBL deficient serum and B. burgdorferi N40 spirochetes (MOI:25). Phagocytosis of CFSE-labeled viable B. burgdorferi N40 by murine macrophages was determined by FACS analysis and expressed as phagocytosis index. Both the experiments in (A,B) are a representative of two independent experiments, samples were performed in triplicates. Bar or symbols represent the mean ± SEM (C). Inflammation based on scoring of H&E staining of skin 6 hours after inoculation of B. burgdorferi. WT: wildtype mouse, MBL −/−: MBL deficient mouse. Bb: experimental groups in which B. burgdorferi N40 was injected intradermally (10⁶ spirochetes per mice in 10 uL). PBS: control groups (n = 2) in which 10 uL PBS was injected intradermally. The experiment was performed twice. Error bars represent mean ± SEM.