Fig. (4) (A) Time course of LPS-induced TNF-α production. THP-1 cells were treated with various LPS concentrations for 5, 17 and 24 hr. At the end of various time points, TNF-α production was measured in THP-1 cells using a homogenous HTRF-based TNF-α assay. Data are from a single experiment performed in quadruplicate, representative of several experiments. (B) Optimization of cell density. THP-1 cells were dispensed at 2k, 3k and 4k per well. After incubated with LPS for 17 hr, TNF-α production in the cells was measured. Data are from a single experiment performed in quadruplicate.