Figure 5.

NBD peptide blocks pro-inflammatory cytokine production by human macrophages in vitro and rheumatoid arthritis (RA) synovial biopsies ex vivo. (a) NBD peptide blocks interleukin (IL)-1-β-induced tumor necrosis factor (TNF)-α production by human macrophages in vitro. Macrophages were pre-incubated with either NBD or mutant NBD (MUT) peptide at a concentration of 50 μM for 2 hours. Subsequently, cells were stimulated with IL-1-β (2.5 ng/ml). After 24 hours, supernatants were collected, and TNF-α levels were measured by sandwich enzyme-linked immunosorbent assay (ELISA). Data are representative of three independent experiments performed in triplicates and are expressed as mean ± standard error of the mean (SEM) (*p < 0.01). (b) NBD peptide blocks TNF-α-induced IL-6 production of RA synovial biopsies ex vivo. Synovial biopsies were cultured with TNF-α (10 ng/ml) in the presence or absence of NBD peptides (100 μM). After 7 days, supernatants were collected and IL-6 levels were measured by sandwich ELISA and corrected for weight of the biopsy. Data are representative of three independent experiments performed in triplicates and are expressed as mean ± SEM (*p < 0.01).