Figure 1
Effect of LPS on IL-8 release by adherent (monocytes) and non-adherent (lymphocytes) cells. Freshly isolated human PBMC (~1.0 × 106 total cells/well, ~100,000 monocytes), as well as adherent and non-adherent cell fractions from the same donor, were prepared as described in Methods in 200 μl of incubation buffer, 100 ng/ml of LBP, and the indicated concentration of endotoxin. Cultures were then incubated at 37°C for 6 h. At the end of the incubation period, cells were pelleted, and buffer samples were frozen at -20°C for subsequent IL-8 analysis by ELISA. Data are expressed as the mean ± S.E.M. of triplicate samples; error bars for some conditions were so small they are obscured by the symbols. **p < 0.001 for total PBMC and non-adherent cells relative to the no LPS control, and in comparison with adherent cells. Similar results were seen in 3 independent experiments and in a parallel series of experiments with N. meningitidis LOS (data not shown).