The results of this investigation led us to conclude that E5564 has a remarkable LPS inhibitory activity manifested via down-regulation of the intracellular generation of pro-inflammatory cytokines IL-6 and TNF-alpha in human monocytes.

The ORL-1 receptor is expressed by all subtypes of leukocytes. The function of this receptor is not the modulation of cytokine production and requires further studies.

In this ex vivo laboratory study, we investigated the effects of drotrecogin alfa (activated) (DA(a)), a recombinant form of human activated protein C, on the intracellular expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha on lipopolysaccharide (LPS)-stimulated human monocytes in a whole blood system. Whole blood samples from 10 healthy volunteers were stimulated with LPS (0.2 ng/mL) and incubated with 0.01, 0.1, 1, 10, and 100 nM of (final concentration) DA(a) for 3 h at 37 degrees C and 5% CO2. Intracellular expression of IL-6 and TNF-alpha was assessed by flow cytometry. Our investigation showed that DA(a), at any of the concentrations tested, did not affect intracellular IL-6 and TNF-alpha production in LPS-stimulated human monocytes after 3 h of incubation. The results of this investigation led us to conclude that any antiinflammatory activity of DA(a), if present, does not occur via detectible decreases in the production of proinflammatory cytokines IL-6 and TNF-alpha in human monocytes.