Figure 4
Effect of LBP on endotoxin-induced superoxide production by PBMC. (A) Freshly isolated human PBMC (~1.0 × 106 total cells/well, 100,000 monocytes) were placed on ice in individual wells of a 96-well white Optiplate in a total volume of 200 μl of incubation buffer containing 0.1 mM lucigenin, 100 ng/ml of LBP, and the indicated concentration of endotoxin. (B) PBMC were prepared under the same conditions with and without 100 ng/ml LBP and the indicated concentration of endotoxin. The plates were then placed in the luminometer and two-sec readings were taken at 37°C every 2 min for 180 min. The resulting readings in relative light units (LU) were summed to provide a measure of activity. Data are expressed as total LU (in thousands) per 100,000 monocytes and represent the mean ± S.E.M. of 4 replicate samples; error bars for some conditions were so small they are obscured by the symbols. (A) **p < 0.001 relative to the no LPS control. (B) *p < 0.05, **p < 0.001 for the 100 ng/ml LBP values relative to the no LBP values at the same LPS concentration. Similar results were seen in 3 independent experiments, and in a parallel series of experiments with N. meningitidis LOS (not shown).