Kolb H, Wörz-Pagenstert U, Kleemann R, Rothe H, Rowsell P, Scott F W
Diabetes Research Institute, Heinrich-Heine-University of Düsseldorf, Germany.
Diabetologia. 1996 Dec;39(12):1448-54. doi: 10.1007/s001250050597.
In diabetes prone BB rat pancreas the Th1/ Th2 cytokine balance and the expression of inducible nitric oxide synthase (iNOS) was determined by mRNA analysis before and after the onset of insulitis. Specific mRNA was amplified by reverse transcriptase polymerase chain reaction, quantitated with radiolabelled probes by phosphoimaging and calibrated with the amount of co-amplified beta-actin mRNA. At 50 days of age, prior to recognizable insulitis, there was already significantly enhanced expression of both, Th1 and Th2 cytokines, and of iNOS mRNA, when compared to Wistar rat pancreas (p < 0.001). This supports the concept of an inconspicuous early phase of islet infiltration by single immunocytes, called single cell insulitis. At 70 days of age mononuclear infiltration of islets had begun and was associated with upregulation of interferon gamma (IFN gamma) and iNOS, but downregulation of interleukin-10 and transforming growth factor beta mRNA (p < 0.001). These findings correlate the onset of insulitis with a shift of the Th1/Th2 cytokine balance towards Th1 cell reactivity. Indeed there was a close correlation of the Th1/Th2 cytokine ratio but not of absolute IFN gamma mRNA levels with the insulitis score. Vaccination at day 50 with tetanus toxoid did not affect cytokine gene expression while diphtheria toxoid and even more strongly BCG administration induced a shift towards Th2 reactivity (p < 0.001) while iNOS mRNA was decreased (p < 0.01). Oral dosing with immunostimulatory components of Escherichia coli also changed the quality of inflammation. Oral lipopolysaccharide (LPS) from E. coli and OM-89, an endotoxin free extract containing immunostimulatory glycolipopeptides and heat shock protein (hsp) 65, both downregulated IFN gamma mRNA while only OM-89 in addition suppressed iNOS mRNA and enhanced Th2 cytokine gene expression (p < 0.001). We conclude that the onset of insulitis is associated with a shift towards Th1 cytokine and iNOS gene expression. Diphtheria toxoid and BCG vaccination stimulates Th2 reactivity but does not downregulate Th1. The latter can be achieved through oral administration of LPS or a glycopeptide fraction (OM-89) from E. coli.
在糖尿病易感BB大鼠胰腺中，通过mRNA分析在胰岛炎发作前后测定Th1/Th2细胞因子平衡以及诱导型一氧化氮合酶（iNOS）的表达。特异性mRNA通过逆转录聚合酶链反应进行扩增，用放射性标记探针通过磷成像进行定量，并以共扩增的β-肌动蛋白mRNA量进行校准。在50日龄时，在可识别的胰岛炎出现之前，与Wistar大鼠胰腺相比，Th1和Th2细胞因子以及iNOS mRNA的表达已经显著增强（p < 0.001）。这支持了单个免疫细胞对胰岛进行不明显早期浸润的概念，即单细胞胰岛炎。在70日龄时，胰岛的单核细胞浸润已经开始，并与干扰素γ（IFNγ）和iNOS的上调相关，但白细胞介素-10和转化生长因子β mRNA下调（p < 0.001）。这些发现将胰岛炎的发作与Th1/Th2细胞因子平衡向Th1细胞反应性的转变相关联。事实上，Th1/Th2细胞因子比率与胰岛炎评分密切相关，但绝对IFNγ mRNA水平与胰岛炎评分无关。在50日龄时用破伤风类毒素进行疫苗接种不影响细胞因子基因表达，而白喉类毒素以及更强的卡介苗接种诱导向Th2反应性的转变（p < 0.001），同时iNOS mRNA减少（p < 0.01）。口服大肠杆菌的免疫刺激成分也改变了炎症的性质。来自大肠杆菌的口服脂多糖（LPS）和OM-89，一种不含内毒素的提取物，含有免疫刺激糖脂肽和热休克蛋白（hsp）65，两者均下调IFNγ mRNA，而只有OM-89还抑制iNOS mRNA并增强Th2细胞因子基因表达（p < 0.001）。我们得出结论，胰岛炎的发作与向Th细胞因子和iNOS基因表达的转变相关。白喉类毒素和卡介苗接种刺激Th2反应性，但不下调Th1。后者可通过口服大肠杆菌的LPS或糖肽组分（OM-89）来实现。
