Figure 11
(A) Endotoxin recovery between native serum, lipoprotein-depleted and lipoprotein-enriched serum in dependence of anticoagulation. Native serum, lipoprotein-enriched and -depleted serum was spiked with heparin (10 IU/mL), citrate (9 mM) or ringer solution for volume compensation in samples without anticoagulation. Endotoxin recovery of 5 ng/mL LPS (E. coli) was determined in the different serum samples. Mean ± standard deviation of three independent experiments are shown. The bars marked with * show a significantly (p < 0.05) difference in endotoxin activity compared to serum without anticoagulants. (B) Monocyte stimulation experiment with LPS, which was incubated in different plasma fractions. LPS was incubated in native serum, lipoprotein-enriched serum and lipoprotein-depleted serum for 24 h. Freshly collected serum blood was spiked (1 ng/mL) with these differently pre-incubated endotoxins. After 4 h incubation at 37 °C the serum levels of TNF-α, IL-1β, IL-6 and IL-8 were determined to test the biological activity of the different pre-incubated endotoxins.
