Figure 2.
Eotaxin-3 is a CCR2 antagonist on monocytes. (A) Changes of [Ca++]i in fura-2–loaded cells sequentially stimulated with eotaxin-3 and MCP-1 at 90-second intervals were monitored. (B) The rate of [Ca++]i rise (% fura saturation/second) induced by MCP-1 was set to 100% and the rate after eotaxin-3 prestimulation was calculated. The results of 1 of 3 independent experiments are shown. (C) MCP-1 (•) or eotaxin-3 (▴)–induced N-acetyl-β-d-glucosaminidase release was assessed in cells treated with cytochalasin-B. Mean values (± SD) of 3 experiments performed with monocytes from different donors are shown. (D) Inhibition of MCP-1–induced N-acetyl-β-d-glucosaminidase release by eotaxin-3 was detected in monocytes sequentially stimulated with increasing concentrations of eotaxin-3 and 10 nM MCP-1. Mean values (± SD) of 3 experiments performed with monocytes from different donors are shown. (E) Monocyte chemotaxis induced by MCP-1 (10 nM) or MCP-1 (10 nM) plus eotaxin-3 (1 μM) was evaluated in Boyden microchambers. Chemotaxis index (mean ± SD) of 3 experiments performed with monocytes from different donors is shown. (F) Eotaxin-3 inhibits MCP-1–induced CCR2 internalization. The histograms represent CCR2 expression on unstimulated cells (dark-filled), cells stimulated with MCP-1 (10 nM; thin line), and cells sequentially stimulated with eotaxin-3 (1 μM) and MCP-1 (10 nM). One representative of 3 experiments performed with monocytes from different donors is shown.