Zeller J M, Sullivan B L
Department of Medical Nursing, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612.
J Leukoc Biol. 1992 Oct;52(4):449-55. doi: 10.1002/jlb.52.4.449.
The acute phase protein, C-reactive protein (CRP), when heat-aggregated (Agg-CRP), potentiates immunoglobulin G (IgG) Fc receptor-mediated luminol-enhanced chemiluminescence (CL) in human monocytes and neutrophils. Luminol-CL is a sensitive measure of phagocyte respiratory burst activity; however, the nature of oxidative products contributing to the light emission and their site of generation remain incompletely defined. To more precisely describe the oxidative burst of monocytes and neutrophils to Agg-CRP, superoxide anion release was measured by cytochrome c reduction. In addition, the extracellular release of hydrogen peroxide was distinguished from hydrogen peroxide generation using a phenol red oxidation assay. Finally, a flow cytometric determination of dichlorofluorescein (DCFH) oxidation was employed as an index of intracellular peroxide production. Although Agg-CRP alone did not stimulate hydrogen peroxide generation by either monocytes or neutrophils, it significantly enhanced hydrogen peroxide generation in response to heat-aggregated IgG (Agg-IgG). In contrast, Agg-CRP did not enhance the extracellular release of either hydrogen peroxide or superoxide anion from Agg-IgG-stimulated cells. The capacity of Agg-CRP to enhance selectively intracellular oxidative product generation was confirmed when measuring DCFH oxidation in Agg-IgG-stimulated cells. To evaluate whether this selective enhancement of intracellular oxidative events could be attributed, at least in part, to a scavenging effect of Agg-CRP, a cell-free oxygen radical-generating system was employed. Agg-CRP did not significantly diminish the lucigenin-amplified CL response induced by the xanthine/xanthine oxidase reaction. These results indicate that although Agg-CRP enhances the intracellular generation of reactive oxygen intermediates by monocytes and neutrophils, extracellular release of those products is not influenced by cell interaction with Agg-CRP. It is tempting to speculate that CRP can selectively boost the microbicidal activities of monocytes and neutrophils within an inflammatory site by amplifying the intracellular generation of reactive oxygen products without increasing damage to surrounding normal tissues.
急性期蛋白C反应蛋白（CRP）经热聚集后（Agg-CRP），可增强人单核细胞和中性粒细胞中免疫球蛋白G（IgG）Fc受体介导的鲁米诺增强化学发光（CL）。鲁米诺-CL是吞噬细胞呼吸爆发活性的一种敏感检测方法；然而，导致发光的氧化产物的性质及其产生部位仍未完全明确。为了更精确地描述单核细胞和中性粒细胞对Agg-CRP的氧化爆发，通过细胞色素c还原法测定超氧阴离子释放。此外，使用酚红氧化试验区分过氧化氢的细胞外释放和产生。最后，采用流式细胞术测定二氯荧光素（DCFH）氧化作为细胞内过氧化物产生的指标。尽管单独的Agg-CRP不会刺激单核细胞或中性粒细胞产生过氧化氢，但它能显著增强对热聚集IgG（Agg-IgG）的过氧化氢产生。相比之下，Agg-CRP不会增强Agg-IgG刺激细胞的过氧化氢或超氧阴离子的细胞外释放。在测量Agg-IgG刺激细胞中的DCFH氧化时，证实了Agg-CRP选择性增强细胞内氧化产物产生的能力。为了评估这种细胞内氧化事件的选择性增强是否至少部分归因于Agg-CRP的清除作用，采用了无细胞氧自由基产生系统。Agg-CRP不会显著降低黄嘌呤/黄嘌呤氧化酶反应诱导的光泽精放大的CL反应。这些结果表明，尽管Agg-CRP增强了单核细胞和中性粒细胞细胞内活性氧中间体的产生，但这些产物的细胞外释放不受细胞与Agg-CRP相互作用的影响。很诱人推测，CRP可以通过放大细胞内活性氧产物的产生而不增加对周围正常组织的损伤，从而选择性地增强炎症部位单核细胞和中性粒细胞的杀菌活性。
