Abstract： Objective To detect the signal pathways through which IL-4 regulates expression of DC-SIGN in THP-1 cells.Methods We used phorbol 12-myristate 13-acetate(PMA) differentiated THP-1 cells as the in vitro model of monocyte/macrophage cells to study the signal pathways involved in IL-4 regulated expression of DC-SIGN.DC-SIGN mRNA expression was detected by RT-PCR.Cytoplasmic DC-SIGN protein was tested by Western blot.Flow cytometry was used to detect cell surface expression of DC-SIGN.Cytoplasm and nuclear protein of PMA stimulated THP-1 cells induced by IL-4 for 0,10,20,30,60 and 120 min was extracted and detected by Western blot for signal pathway signaling protein and phosphoprotein.Results We found that a high expression of DC-SIGN could be induced by IL-4 at the levels of mRNA and cell surface protein.Up-regulated expression of DC-SIGN was almost completely blocked by the specific inhibitor of ERK pathway,and partly reduced by the specific inhibitors of JAK-STAT and NF-κB pathways.The activation of the three signaling pathways was directly confirmed by testing the phosphorylation of protein kinase within the cytoplasm and nucleus over time.Conclusion Multiple signaling pathways are involved in IL-4 induced high expression of DC-SIGN on THP-1 cells,in which ERK pathway is the main signal pathway.