REGULATION OF CYTOKINE PRODUCTION BY IL-10 IN ENDOTOXIN-STIMULATED MONOCYTES

细菌内毒素，脂多糖(LPS)，诱导表达 人类单核细胞中的多种早期反应基因，包括 促炎细胞因子：肿瘤坏死因子-a、白介素1b和白介素6。IL-10的表达 在单核细胞中也是内毒素诱导的，相对于肿瘤坏死因子-α的诱导是延迟的， IL-1b和IL-6。IL-10反馈抑制这些细胞因子的表达， 以及IL-10本身，从而提供了一种有效的机制 控制单核细胞中细胞因子的产生。Th1型淋巴因子， 干扰素-g显著上调人肿瘤坏死因子-a的产生 单核细胞。在这个项目中，我们正在研究干扰素-g的作用。 内毒素刺激单核细胞表达IL-10的研究我们还在研究 干扰素-g刺激后IL-10与肿瘤坏死因子-α水平的关系 细胞。内毒素刺激诱导细胞因子快速有序表达 MRNA.稳定状态下，肿瘤坏死因子-α的mRNA水平迅速升高，达到最高水平 水平在刺激后2-3小时，然后急剧下降。IL-1b和 IL-6mRNA水平在内毒素刺激后也显著升高， 但下降速度慢于肿瘤坏死因子-α。下调肿瘤坏死因子-α的基因表达， IL-1b和IL-6与IL-1b和IL-6呈延迟性和渐进性升高相一致 10m RNA水平。此外，内源性IL-10的中和作用 抗IL-10抗体延长肿瘤坏死因子-αmRNA的表达，并显著 增加肿瘤坏死因子的产生。干扰素-γ抑制IL-10mRNA的表达 内毒素刺激单核细胞，并在一定剂量下减少IL-10的净产生- 依赖的态度。IL-10mRNA水平的降低与 肿瘤坏死因子-αm RNA的大小和持续时间均显著增加 表情。因此，干扰素-g诱导的肿瘤坏死因子-α的产生增强 单核细胞与抑制内源性IL-10的表达有关。在……里面 在未来的实验中，我们将尝试通过以下方式定义分子机制 IL-10下调细胞因子的产生，特别是肿瘤坏死因子-α，在 内毒素刺激单核细胞。

The bacterial endotoxin, lipopolysaccharide (LPS), induces expression of multiple early response genes in human monocytes, including the proinflammatory cytokines TNF-a, IL-1b and IL-6. IL-10 expression, which is also LPS-inducible in monocytes, is delayed relative to that of TNF-a, IL-1b and IL-6. IL-10 feedback inhibits expression of these cytokines, as well as IL-10 itself, thereby providing an efficient mechanism for controlling cytokine production in monocytes. The Th1-type lymphokine, interferon-g (IFN-g), markedly upregulates TNF-a production in human monocytes. In this project, we are investigating the effects of IFN-g on IL-10 expression in LPS-stimulated monocytes. We are also examining the relationship between between IL-10 and TNF-a levels in IFN-g-primed cells. LPS stimulation induces rapid and ordered expression of cytokine mRNA. Steady-state mRNA levels for TNF-a increase rapidly, reach maximum levels by 2-3 hr post stimulation, and then decline sharply. IL-1b and IL-6 mRNA levels also increase markedly following stimulation with LPS, but decrease more slowly than TNF-a. Downregulation of mRNA for TNF-a, IL-1b and IL-6 coincides with a delayed amd more gradual increase in IL- 10 mRNA levels. Furthermore, neutralization of endogenous IL-10 with anti-IL-10 antibody prolongs TNF-a mRNA expression, and significantly increases TNF production. IFN-g inhibited expression of IL-10 mRNA in LPS-stimulated monocytes, and decreased net IL-10 production in a dose- dependent manner. The reduction in IL-10 mRNA levels was associated with a marked increase in both the magnitude and duration of TNF-a mRNA expression. Thus, potentiation of TNF-a production in IFN-g-primed monocytes is coupled to inhibition of endogenous IL-10 expression. In future experiments, we will attempt to define the molecular mechanism by which IL-10 downregulates cytokine production, particularly TNF-a, in LPS-stimulated monocytes.