During inflammatory processes Eotaxin stimulates the production of myeloid progenitors in the BM. Mice were sensitized with intraperitoneal OVA on day 0 followed by exposure to aerosolized OVA on day 8 and on days 15 through 21 (A). In a murine model of lung allergic inflammation, administration of neutralizing antibodies to Eotaxin (◊) prevented the increase in the number of granulocyte-macrophage colony-forming units (GM-CFU/BM) in the BM during the inflammatory phase between days 15 and 21 (⧫)22 (B). In vivo administration of Eotaxin increased the number of GM-CFU present in the BM (C). The increase in the number of blood neutrophils in the blood of OVA-treated mice is shown in (D). Each point is the mean of three determinations ± standard deviation (SD). For each panel the significance of differences between treated and untreated groups of mice were determined by a standard Student's t-test.