Lipopolysaccharide-binding protein inhibitory peptide inhibits the binding of LPS to U937 cells

AIM: To investigate the inhibitory effect of P12, a kind of lipopolysaccharide (LPS)-binding protein (LBP) inhibitory peptide, on the binding of LPS to macrophage in vitro. METHODS: Human monocyte-like cell line (U937 cells) was grown in RPMI-1640 and stimulated with PMA in order to induce their differentiation to macrophage stage. The relative affinity of P12 to LPS was determined by enzyme-linked immunosorbent assay (ELISA). The effects of P12 on the binding of LPS to U937 cells were determined by flow cytometry analysis. The production of tumor necrosis factor-alpha (TNF-α) was measured by ELISA. RESULTS: The relative binding activity of P12 to LPS was higher than that of LBP in the same mass concentration. P12 inhibited the binding of FITC-conjugated LPS (FITC-LPS) to U937 cells. The productions of TNF-α was also significantly suppressed by P12. CONCLUSION: The results suggest that blockage of LBP at the inflammatory sites might attenuate LPS-induced circulatory shock.