In this study, we preliminarily investigated the mechanism of internalization of CCR9 on MOLT4 cell model (a human leukemia T-cell line, naturally expresses CCR9) and found that IL-2 upregulated the cell surface expression of IL-4Ralpha (CD124) greatly, whereas IL-4 had no significant influence on alpha (CD25) and beta subunits (CD122) of IL-2R.
Here, we report that IL-2-dependent ATL cell lines also express IL-4Ralpha and respond to IL-4, which was verified by the activation of cytoplasmic transcriptional activator Stat6 protein.
These results indicate the activation of IL-4/IL-4 receptor system in leukemic cells from some ATL patients and suggest the possible involvement of the system in the proliferation of leukemic cells and the leukemogenesis in ATL.