The effect of IV eotaxin on blood and bone marrow eosinophil numbers. After injection of eotaxin, circulating eosinophil numbers were determined at multiple time points over a 2-hour period. Femoral marrow eosinophil numbers were determined after 2 hours. (A) Kinetics of blood eosinophilia induced by eotaxin (1 nmol/kg). Results show the number of eosinophils per milliliter of blood at each time point, mean ± SEM (n = 4 animals). Eotaxin stimulated a significant *(P < .05) or **(P < .01) blood eosinophilia after 15 minutes compared with the vehicle-injected group. (•), Eotaxin 1 nmol/kg; (○), Vehicle. (B) Femoral marrow eosinophil numbers. Results show the total number of morphologically mature eosinophils in femoral bone marrow in one femur 2 hours after injection of eotaxin (1 nmol/kg) or vehicle, mean ± SEM, (n = 4 animals). A significant difference between eotaxin- and vehicle-injected groups is shown by *(P < .05).