Figure 4.
Endocytosis-independent induction of pro-inflammatory cytokines. THP-1 cells (2 × 105 cells/500 μl) were cultured in the presence of 1.0 μm cytochalasin D or 100 nm bafilomycin A1 for 1 hr, and treated with 50 μl of living or heat-killed Mycoplasma pneumoniae (OD595 = 0.1). After 6 hr incubation, amounts of tumour necrosis factor-α (TNF-α) (a) and interleukin-1β (IL-1β) (b) in culture medium were measured by ELISA. Cells were harvested and the induction levels of pro-IL-1β precursor were determined by Western blotting (c). All values represent the means and SD of three assays. An asterisk indicates that the P-value is < 0.01 for a comparison with PBS treatment by multiple comparison.