Weber C, Aepfelbacher M, Haag H, Ziegler-Heitbrock H W, Weber P C
Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, University of Munich, FRG.
Eur J Immunol. 1993 Apr;23(4):852-9. doi: 10.1002/eji.1830230413.
Human Mono Mac 6 cells exhibit characteristics of mature blood monocytes. Treatment of these cells with human recombinant human tumor necrosis factor (TNF) resulted in an increase in phagocytosis and phorbol myristate acetate-stimulated superoxide anion production at 12 h and growth retardation occurring at 24 h. Moreover, TNF induced a moderate increase of CD14 surface antigen expression, used as a phenotypic marker of monocyte/macrophage differentiation. Platelet-activating factor (PAF) stimulated a rapid rise in cytosolic free Ca++ ([Ca++]i) of 308 +/- 93 nM in TNF-treated cells compared to untreated cells (33 +/- 8 nM, n = 4). The effect of TNF was dose and time dependent, evident after 12 h and maximal at 48 h. The enhanced PAF-induced [Ca++]i rise was inhibited by the PAF receptor antagonist L-659,989 and EGTA, indicating receptor-dependent Ca++ influx. Furthermore, L-659,989 and PAF inhibited specific 3H-labeled PAF binding in TNF-treated, but not in untreated cells. Consistently, PAF stimulated arachidonic acid release only in TNF-treated cells. Preincubation of cells with anti-TNF monoclonal antibodies abolished TNF-induced effects, but failed to block lipopolysaccharide (LPS) effects. Distinct mechanisms of action by LPS were reflected by the different ability to induce surface antigen expression. In conclusion, the enhancement of PAF responses by TNF, associated with functional characteristics of differentiation in Mono Mac 6 cells, may represent a specific mechanism of cooperative interaction between PAF and TNF in inflammation, sepsis, immunoregulation and atherogenesis.
人单核巨噬细胞6细胞表现出成熟血液单核细胞的特征。用人重组人肿瘤坏死因子（TNF）处理这些细胞，导致12小时时吞噬作用增加，佛波酯肉豆蔻酸酯刺激的超氧阴离子产生增加，24小时时出现生长迟缓。此外，TNF诱导CD14表面抗原表达适度增加，CD14用作单核细胞/巨噬细胞分化的表型标志物。与未处理的细胞（33±8 nM，n = 4）相比，血小板活化因子（PAF）刺激TNF处理的细胞中胞质游离Ca++（[Ca++]i）迅速升高至308±93 nM。TNF的作用呈剂量和时间依赖性，12小时后明显，48小时时达到最大值。PAF受体拮抗剂L-659,989和EGTA抑制了PAF诱导的[Ca++]i升高增强，表明受体依赖性Ca++内流。此外，L-659,989和PAF抑制了TNF处理的细胞中特异性3H标记的PAF结合，但未处理的细胞中未出现这种情况。一致地，PAF仅在TNF处理的细胞中刺激花生四烯酸释放。用抗TNF单克隆抗体预孵育细胞消除了TNF诱导的效应，但未能阻断脂多糖（LPS）的效应。LPS诱导表面抗原表达的不同能力反映了其不同的作用机制。总之，TNF增强PAF反应，与单核巨噬细胞6细胞的分化功能特征相关，可能代表了PAF和TNF在炎症、脓毒症、免疫调节和动脉粥样硬化发生中协同相互作用的一种特定机制。
