Weber Martin S, Starck Michaela, Wagenpfeil Stefan, Meinl Edgar, Hohlfeld Reinhard, Farina Cinthia
Institute for Clinical Neuroimmunology, Marchioninistrasse 15, D-81377 Munich, Germany.
Brain. 2004 Jun;127(Pt 6):1370-8. doi: 10.1093/brain/awh163. Epub 2004 Apr 16.
It is widely assumed that glatiramer acetate (GA), an approved agent for the immunomodulatory treatment of multiple sclerosis, acts primarily as an antigen for T lymphocytes. Recent studies, however, indicated that in vitro, GA directly inhibits dendritic cells, a rare but potent type of professional antigen-presenting cell (APC). To investigate whether these in vitro observations are relevant to the actions of GA in vivo, we studied the effects of GA on monocytes, the major type of circulating APC. In a first series of experiments, we investigated the effects of GA on monocyte reactivity in vitro. Monocytes were stimulated with ligands for Toll-like receptor (TLR)-2 (peptidoglycan and lipoteichoic acid), TLR-4 [lipopolysaccharide (LPS)] and TLR-5 (flagellin), as well as two proinflammatory cytokines (interferon-gamma and granulocyte-monocyte colony-stimulating factor). Monocyte activation was measured by induction of the surface markers signalling lymphocytic activation molecule (SLAM), CD25 and CD69 (detected by cytofluorometry), and by production of monocyte-derived tumour necrosis factor (TNF)-alpha (detected by enzyme-linked immunospot assay). GA had a broad inhibitory effect on all measures of monocyte reactivity, regardless of which stimulator was used. It is unlikely that this reflects a simple toxic effect, because monocyte viability and CD14 expression were unaffected. In a second series of experiments, we investigated the properties of monocytes cultured ex vivo from eight GA-treated multiple sclerosis patients, eight untreated multiple sclerosis patients and eight healthy subjects. We found that LPS-induced SLAM expression and TNF-alpha production were significantly reduced in monocytes from GA-treated patients compared with controls. These results demonstrate for the first time that GA inhibits monocyte reactivity in vitro and in vivo, significantly extending the current concept of the mechanism of action of GA.
人们普遍认为，醋酸格拉替雷（GA）作为一种已获批准用于多发性硬化症免疫调节治疗的药物，主要作为T淋巴细胞的抗原发挥作用。然而，最近的研究表明，在体外，GA可直接抑制树突状细胞，这是一种罕见但强大的专职抗原呈递细胞（APC）。为了研究这些体外观察结果是否与GA在体内的作用相关，我们研究了GA对单核细胞（循环APC的主要类型）的影响。在第一系列实验中，我们研究了GA对体外单核细胞反应性的影响。用Toll样受体（TLR）-2（肽聚糖和脂磷壁酸）、TLR-4[脂多糖（LPS）]和TLR-5（鞭毛蛋白）的配体以及两种促炎细胞因子（干扰素-γ和粒细胞-单核细胞集落刺激因子）刺激单核细胞。通过诱导表面标志物信号淋巴细胞激活分子（SLAM）、CD25和CD69（通过细胞荧光测定法检测）以及单核细胞衍生的肿瘤坏死因子（TNF）-α的产生（通过酶联免疫斑点测定法检测）来测量单核细胞活化。无论使用哪种刺激物，GA对单核细胞反应性的所有指标都有广泛的抑制作用。这不太可能反映一种简单的毒性作用，因为单核细胞活力和CD14表达未受影响。在第二系列实验中，我们研究了从八名接受GA治疗的多发性硬化症患者、八名未治疗的多发性硬化症患者和八名健康受试者体外培养的单核细胞的特性。我们发现，与对照组相比，GA治疗患者的单核细胞中LPS诱导的SLAM表达和TNF-α产生显著降低。这些结果首次证明GA在体外和体内均抑制单核细胞反应性，显著扩展了目前关于GA作用机制的概念。
