目的 :比较两型TNF α对单核细胞系U937细胞功能的影响 ,以探讨跨膜型TNF α在炎症中的作用。方法 :通过吞噬、RT PCR、Westernblot及FACS等方法 ,比较两型TNF α对U937细胞生物学功能 (包括吞噬、细胞因子mRNA、胞质IκB α及ICAM 1表达等 )的影响。结果 :分泌型TNF α可明显促进U937细胞吞噬功能 ,使TNF α、IL 1β及IL 8mRNA积累增加 ,促进胞质IκB α降解及提高黏附分子ICAM 1的表达 ;而跨膜型TNF α对上述U937细胞的生物学功能则无明显影响。当二者联用时 ,跨膜型TNF α与分泌型TNF α亦无协同作用。结论 :分泌型TNF α对U937细胞具有明显地激活作用 ;而跨膜型TNF α则无影响 ,提示两型TNF α在炎症过程中的作用不同。 Objective: To compare the effects of two types of TNFα on the function of monocytic cell line U937 in order to explore the role of transmembrane-type TNFα in inflammation. Methods: The effects of two types of TNFα on the biological functions of U937 cells including phagocytosis, cytokine mRNA, cytoplasmic IκBα and ICAM 1 expression were compared by phagocytosis, RT PCR, Western blot and FACS. Results: Secretion of TNFα significantly promoted the phagocytosis of U937 cells, increased the accumulation of TNFα, IL 1β and IL 8 mRNA, promoted the degradation of IκBα and increased the expression of ICAM 1. The biological function of cells has no significant effect. When the combination of the two, transmembrane TNFα and secreted TNFα no synergistic effect. CONCLUSION: Secreted TNFα can obviously activate U937 cells, while transmembrane TNFα has no effect, suggesting that TNFα plays different roles in inflammation.