Eotaxin-3 is a repulsive factor for human monocytes. (A) Monocyte chemotaxis was evaluated in 24-transwell chambers. Cells were preincubated with or without 1 μM eotaxin-3, and migration induced by MCP-1 (10 nM) was assessed. Data are expressed as chemotaxis index (mean ± SD) of 8 experiments performed with monocytes from different donors. (B) Inhibition of the repulsive effect of eotaxin-3 by MCP-1 and truncated analogs of MCP-1 and RANTES was assessed in Boyden microchambers. Cells were preincubated with 1 μM eotaxin-3 and 1 μM of the following chemokines: MCP-1, MCP-1 (9-76) and RANTES (9-68) as indicated. Data are expressed as chemotaxis index (mean ± SD) of 3 experiments performed with monocytes from different donors. Differences that are statistically significance are indicated. (C) Inhibition of the repulsive effect of eotaxin-3 (filled bars) and of the synergistic effect of opposing gradients of MCP-1 and eotaxin-3 (hatched bars), by the Gαi inhibitor B pertussis toxin, and the tyrosine kinase inhibitor genistein. Migration of untreated cells = 100%. Percent of migration ± SD of 5 experiments performed with monocytes from different donors. Statistically significant differences (P < .01) between untreated and monocytes treated with B pertussis toxin or genistein are indicated with an asterisk.
