FIG. 3.

Effects of LPS-37 on the phagocytosis of bacteria by U937 cells. A total of 5 × 10⁴ U937 cells/well were cultured in 96-well plates in the presence of cytochalasin D, LPS-37, or anti-TLR4 antibody for 1 h. The culture supernatant was then removed, and fluorescein isothiocyanate-labeled E. coli K-12 BioParticles were added at a dose of 5 × 10⁷/well. The cells were cultured for 2 h to phagocytose the E. coli particles and were then treated with trypan blue to quench the extracellular fluorescence. The intensity of the fluorescence associated with intracellular fluorescent particles was then measured with a microplate fluorometer. Intensity is presented as relative fluorescence units. The data presented represent the means from triplicate assays; the error bars indicate ranges and are representative of the results of three experiments. *, P < 0.05 compared to the results for the control, as determined by Student's t test; **, P < 0.01 compared to the results for the control, as determined by Student's t test.