OBJECTIVETo express and purify recombinant human interleukin-35[IL-35-IgG1 (Fc) in eukaryotic expression system and to study the interaction of IL-35 with gp130 protein.

METHODSA mammalian expression vector, pSTEP2-IL35-LFc, was constructed and transfected into HEK293T cells. Then rhIL-35-IgG1 (Fc) was expressed and purified with protein A affinity chromatography, and was examined with SDS-PAGE and Western blot analysis. The binding of IL-35 to its receptor gp130 was investigated using enzyme-linked immunosorbent assay (ELISA). The biological effect of IL-35 on gp130 was explored in M1 myeloid leukemia cells.

RESULTSrhIL-35-Fc with high purity on reduced SDS-PAGE was obtained. ELISA confirmed that IL-35-Fc was bound to gp130 and neutralized the function of gp130 in M1 myeloid leukemic cells.

CONCLUSIONSHigh-purity and biologically active rhIL-35-Fc protein successfully produced in this study. IL-35 binds to gp130 and neutralizes its activity of in M1 myeloid leukemic cells.