促癌剂十四酰佛波乙酸酯(PMA)对细胞免疫的影响 Ⅳ.PMA对小鼠树突状细胞的影响

Effect of the Tumor Promoter Phorbol Myristate Acetate (PMA) on Cell-mediated Immunity Ⅳ. PMA-lnduced Modulation of Mouse DendriticCell Function

PMA是一种强促癌剂,对其促癌机理已有大量深入的研究.我们以往的工作表明,PMA对细胞免疫功能也有多方面的影响。其中,PMA对小鼠脾粘附细胞的免疫扶佐功能的抑制作用尤为明显.树突状细胞(deadritic cell,DC)是一类有很强免疫扶佐活性的细胞群。本文报道,从小鼠脾粘附细胞中分离纯化DC,观察经PMA预处理的DC在初级混合淋巴细胞反应(I°MLR)和氧化物刺激的淋巴细胞增殖反应中的免疫扶佐功能的改变.

In the present study we investigated the in vitro effects of the tumor promoter phorbol myristate acetate (PMA) on the accessory function of mouse spleen dendritic cells (DC) in mitogenesis. The effects of the PMA, a protein kinase C (PKC) activator, depended on dose. If pretreated with<50 ng/ml of PMA for 3 h, DC activity was enhanced by about two-fold; whereas ≥200 ng/ml of PMA decreased DC activity with an inhibition rate about 50%(in early response DC activity showed a moderate increase). Our results indicate that the function of DC, a potent accessory population, can be further enhanced by a low dose of PMA. This is circumstantial evidence that DC activity can be up-regulatal via PKC activation. That a high dose of PMA inhibits DC activity might be a mechanism by which PMA promotes carcino-genesis.