Objective:To clarify whether IL-10 enhanced the M2 phenotype induced by IL-4.Methods:M-CSF induced bone marrow-derived macrophages ( BMDMs) were generated from C57BL/6J mice bone marrow cells.The RNA transcriptional profile was e-valuated using the Mouse Whole Genome.We performed in vitro eosinophil migration assay and in vivo macrophage transfer.Results:The results showed that IL-10 enhanced gene expression of M2a markers induced by IL-4 in M-CSF-induced BMDMs.Moreover,IL-4 and IL-10 synergistically induced CCL24 ( Eotaxin-2) production.Enhanced CCL24 expression was also observed in GM-CSF-induced BMDMs and zymosan-elicited,thioglycolate-elicited and naive peritoneal macrophages.CCL24 was a CCR3 agonist and an eosinophil chemoattractant.In vitro,IL-4+IL-10-stimulated macrophages produced a large amount of CCL24 and increased eosinophil migration, which was inhibited by anti-CCL24 antibody.IL-4+IL-10-stimulated ( but not IL-4 or IL-10 alone) macrophages transferred into the peritoneumof C57BL/6J mice increased eosinophil infiltration into the peritoneal cavity.Conclusion:These results demonstrate that IL-4+IL-10-simulated macrophages have enhanced M2a macrophage-related gene expression,CCL24 production and eosinophil infiltration-inducing activity,thereby suggesting theircontribution to eosinophil-related diseases.