Figure 6.

Factor H-related (FHR)-B enhances complement activation on human umbilical vein endothelial cell (HUVEC)-derived extracellular matrix (ECM). HUVEC cells were cultured on gelatin-coated 96-well tissue culture plates for 7 days. After removal of the cells, the cell-derived ECM was blocked, washed and incubated with 5% mouse serum in Dulbecco’s phosphate-buffered saline (DPBS)⁺⁺ (A) or in DPBS containing 5 mM Mg²⁺-EGTA (B) for 30 min at 37°C with 5 and 10 µg/mL FHR-B or 10 µg/mL human serum albumin (HSA) as control. As an additional negative control, serum diluted in 20 mM EDTA buffer was used to block complement activation. Complement activation was detected by measuring C3-deposition using horseradish peroxidase (HRP)-conjugated mouse C3-specific antibody. Data are mean absorbance values + SD derived from three independent experiments. *p < 0.05, ***p < 0.001, one-way ANOVA.