Thrombin-derived peptides modulate the cytokine response to LPS in vitro. (A and B) Measurement of nitrite release of RAW 264.7 macrophages stimulated with 10 ng/ml E. coli or P. aeruginosa LPS in combination with the indicated concentrations of GKY25 and HVF18 (n = 3). (C and D) RAW 264.7 cells were stimulated with 10 ng/ml E. coli LPS and cytokines were analysed in the cell supernatants (n = 3). (E and F) Human blood was treated with 10 ng/ml E. coli LPS alone, or with LPS and GKY25 (E) or HVF18 (F). After 6 h of incubation TNF-α was determined in plasma by ELISA (n = 3). (G) Binding of GKY25 and WFF25 to 125I -labeled E. coli LPS using a slot blot assay. (H) Stimulation of RAW 264.7 cells by LPS and the effects of peptides. Left panel: LPS was incubated with GKY25 or WFF25, followed by addition of serum and incubation with the cells. Right panel: Standard procedure as in A. Peptides were added to cells pre-incubated briefly with LPS in <t>DMEM</t> with 10% <t>FBS</t> (n = 3).