Fig. 4.

Monocyte chemotactic activity in supernatants of endothelial cells. Monolayers of endothelial cells were stimulated with 100 U/ml recombinant human IL-β, or incubated with 5 × 10⁷ strain 42D or with 1 × 10⁷ strain CAPD for 60 min at 37°C. After washing and lysostaphin treatment, the endothelial cells were subsequently cultured. At different time points, culture supernatants were harvested and tested for chemotactic activity towards human monocytes. A representative experiment is shown. Data are expressed as the ratio between the number of migrated monocytes towards culture supernatant of infected or IL-1-β-stimulated endothelial cells and the number of migrated monocytes towards culture supernatant of untreated endothelial cells. Chemotaxis was tested in the presence (□) or absence (▪) of neutralizing anti-MCP-1 antibody.