The effect of IL-5 on eotaxin-stimulated chemotaxis of guinea pig bone marrow eosinophils. Bone marrow leukocytes were preincubated with IL-5 (3 nmol/L) or vehicle for 15 minutes at 37°C. (A) The effect of IL-5 (3 nmol/L, upper chamber) on bone marrow eosinophil chemotaxis induced by eotaxin (0 to 30 nmol/L, lower chamber). Data represent the number of eosinophils migrated after 1 hour, mean ± SEM of a single cell preparation performed in triplicate. (•), IL-5 3 nmol/L; (○), Vehicle. (B) The effect of IL-5 (3 nmol/L) and eotaxin (0.3 nmol/L) alone or in combination on the chemotaxis of bone marrow eosinophils (results from experiment shown in Fig 5A). Results represent the number of eosinophils migrated after 1 hour, mean ± SEM of a single cell preparation performed in triplicate. The results shown are representative of three identical experiments. Significant difference between IL-5 alone and vehicle indicated by †(P < .05), or between eotaxin together with IL-5 and IL-5 alone by *(P < .05).