Gessani S, Testa U, Varano B, Di Marzio P, Borghi P, Conti L, Barberi T, Tritarelli E, Martucci R, Seripa D
Department of Virology, Istituto Superiore di Sanità, Rome, Italy.
J Immunol. 1993 Oct 1;151(7):3758-66.
In vitro cultivated human monocytes isolated from normal peripheral blood show a time-dependent differentiation into macrophages characterized by an increased expression of transferrin receptors, CD11/CD18, and CD14 Ag. We measured the secretion of TNF-alpha and IL-6 in freshly isolated monocytes and in differentiated macrophages after LPS treatment. Differentiated macrophages produced significantly higher amounts of TNF-alpha and IL-6 than freshly isolated monocytes. This increased secretion was not a result of an enhanced accumulation of TNF-alpha and IL-6 mRNA, as comparative levels of these transcripts were found in both cell types after LPS treatment. Furthermore, LPS did not induce an antiviral state to VSV3 in monocytes, but it reduced by 3 to 5 log10 the virus yield in differentiated macrophages. The addition of antibodies to IFN-beta completely inhibited the LPS-induced antiviral state to VSV, but antibodies to IFN-alpha, TNF-alpha, or IL-6 were ineffective. A marked accumulation of IFN-beta mRNA was found in both cell types after LPS treatment. Binding experiments with FITC-LPS revealed a slightly higher overall binding affinity for LPS in freshly explanted monocytes as compared with differentiated macrophages, even though the maximal binding was higher in macrophages. In both cell types, the LPS binding was partially inhibited by antibodies to CD14. These results demonstrate that: 1) in vitro differentiation of human monocytes to macrophages leads to an enhanced LPS response in terms of (a) progressive increase of IL-6/TNF-alpha production and (b) acquisition of an IFN-beta mediated antiviral state; 2) this enhanced response to LPS, largely CD14-independent, is not linked to any increased accumulation of cytokine mRNA, but is probably a result of an increased synthesis and/or secretion of these cytokines.
从正常外周血中分离出的体外培养的人单核细胞显示出随时间依赖的向巨噬细胞的分化，其特征为转铁蛋白受体、CD11/CD18和CD14抗原的表达增加。我们测量了脂多糖（LPS）处理后新鲜分离的单核细胞和分化巨噬细胞中肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）的分泌情况。分化的巨噬细胞产生的TNF-α和IL-6量明显高于新鲜分离的单核细胞。这种分泌增加并非TNF-α和IL-6 mRNA积累增强的结果，因为在LPS处理后的两种细胞类型中发现这些转录本的相对水平是相同的。此外，LPS并未在单核细胞中诱导针对水疱性口炎病毒（VSV3）的抗病毒状态，但它使分化巨噬细胞中的病毒产量降低了3至5个对数10。添加抗干扰素-β（IFN-β）抗体完全抑制了LPS诱导的针对VSV的抗病毒状态，但抗IFN-α、TNF-α或IL-6抗体则无效。LPS处理后在两种细胞类型中均发现IFN-β mRNA有明显积累。用异硫氰酸荧光素（FITC）标记的LPS进行的结合实验表明，与分化的巨噬细胞相比，新鲜分离的单核细胞对LPS的总体结合亲和力略高，尽管巨噬细胞中的最大结合量更高。在两种细胞类型中，LPS结合均被抗CD14抗体部分抑制。这些结果表明：1）人单核细胞在体外分化为巨噬细胞导致LPS反应增强，表现为（a）IL-6/TNF-α产生的逐渐增加和（b）获得IFN-β介导的抗病毒状态；2）这种对LPS的增强反应在很大程度上不依赖于CD14，与细胞因子mRNA的任何增加积累无关，但可能是这些细胞因子合成和/或分泌增加的结果。
