肝癌细胞系(PLC/PRF/S)的免疫抑因子的分离及其特征

Isolation and characterization of an immunosuppressive factor from a hepatoceliular carcinom a cell line(PLC/PRF/5)

应用中和人肝癌细胞系(PLC/PRF/5)培养上清抑制NK 活性的单克隆抗体亲和层折从PLC/PRF/5细胞提取液中分离纯化免疫抑制因子。分离的免疫抑制因子电泳分析表明为42KD 的多肽,它抑制PHA 或IL-2刺激正常外周血单个核细胞的~3H 胸腺嘧啶掺入,这种抑制作用随免疫抑制因子浓度的增加(从17μg/ml 到140μg/ml)而增强(抑制率从10%到99%)。在培养中一定量的IL-2能部份或全部消除一定浓度的免疫抑制因子的抑制作用。这一免疫抑制因子还具有抑制PHA 诱导单个核细胞的IL-2表达和抑制NK 活性等生物学特征.

From the cell extract of a human hepatoceltular carcinoma cell line (PLC/PRF/5),an im- munosuppressive factor,a polypeptide with a relative molecular mass of 42 KD was isolated byaffinity chromotography with AH- Sepharose 4B coated with a monoclonal antibody whichraised against PLC/PRF/5 cells,and which can neutralize the inhibition of NK activity causedby superna tant of PLC/PRF/5 cell.The factor was characterized by PAGE electrophoresis andWestern Blot analysis.Biological assay showed that the factor isolated suppresses PHA—inducedor IL—2—stimulated ~3H—thymidine uptake of peripheral blood mononuclear ceils (PBM).This suppression was dosedependent,and ranged from 100% to 99% when the concentration ofthe factor varied from 17 μg/ml to 140μg/ml in culture media.However,the suppression of thefactor on PBM in response to IL—2 was decreased by increasing the dose of IL—2 in the cellculture.This factor also suppresses the expression of IL—2 by PHA—induced PBM,as well asthe NK activity of the peripheral blood lymphocytes.