Role of JAK2 signal transductional pathway in activation and survival of human peripheral eosinophils by interferon-gamma (IFN-γ)

The purpose of this study was to determine whether the JAK pathway is involved in eosinophil activation and survival through IFN-γ receptor signalling in human peripheral eosinophils. Eosinophils were purified from the blood of six atopic disease patients by anti-CD16 magnetic bead-negative selection. IFN-γ significantly up-regulated survival and CD69 expression in 24–48 h cultured eosinophils. Further, IFN-γ induced tyrosine phosphorylation of JAK2 in eosinophils, as indicated by Western blot analysis. Finally, the specific JAK2 inhibitor AG-490 inhibited the tyrosine phosphorylation of JAK2, IFN-γ-induced survival and CD69 expression in eosinophils. In conclusion, these results indicate that IFN-γ induces eosinophil survival and CD69 expression through the activation of JAK2 in peripheral eosinophils, suggesting that JAK2 may play a significant role in eosinophil regulation by IFN-γ–IFN-γR interaction.