The James Hogg iCAPTURE Centre, St. Paul's Hospital, Department of Medicine, University of British Columbia, Vancouver, B.C., Canada.
Int Arch Allergy Immunol. 2010;152(1):12-27. doi: 10.1159/000260079. Epub 2009 Nov 24.
Although the accepted paradigm is that the proteins stored in eosinophil crystalloid granules are translated from messenger RNA transcribed in the cell nucleus, recent ultrastructural evidence suggests that protein synthesis may also take place within eosinophilic granules.
We used 2 different methods to detect the presence of DNA and RNA in eosinophil secretory granules. Using bromodeoxyuridine, a thymidine analogue, and bromouridine, a uracil analogue, we labeled the DNA and RNA in eosinophils in vivo in rabbits. Immunoelectron microscopy to localize these molecules was performed on ultrathin sections of blood and bone marrow eosinophils using monoclonal anti-bromodeoxyuridine antibody with IgG as a control. The immunogold grain density was measured in each subcellular compartment within the eosinophils and analyzed using image analysis software. A combination of DNA/CD63 immunofluorescence staining and a fluorescently labeled molecular probe that stains RNA was used to examine the presence of DNA and RNA in the secretory granules of human blood eosinophils.
The mean density of bromodeoxyuridine-labeled DNA and bromouridine-labeled RNA immunogold grains in the secretory granules of blood and bone marrow eosinophils were significantly higher (p < 0.0005) than cytoplasmic or background staining. We also demonstrated the existence of DNA and RNA in the CD63-positive secretory granules of human peripheral blood eosinophils by means of immunofluorescent staining and a fluorescently labeled molecular probe.
These results provide evidence that eosinophil granules are the site of DNA and RNA synthesis and suggest the potential for a new role(s) for eosinophil-secretory granules.
尽管被广泛接受的观点认为，嗜酸性粒细胞晶状颗粒中储存的蛋白质是由细胞核中转录的信使 RNA 翻译而来的，但最近的超微结构证据表明，蛋白质合成也可能发生在嗜酸性粒细胞颗粒内。
我们使用了 2 种不同的方法来检测嗜酸性粒细胞分泌颗粒中 DNA 和 RNA 的存在。我们使用溴脱氧尿苷（一种胸苷类似物）和溴尿嘧啶（一种尿嘧啶类似物）标记了兔体内嗜酸性粒细胞中的 DNA 和 RNA。使用单克隆抗溴脱氧尿苷抗体（以 IgG 作为对照）对血液和骨髓嗜酸性粒细胞的超薄切片进行免疫电镜，以定位这些分子。在嗜酸性粒细胞的每个亚细胞区室中测量这些免疫电镜金颗粒的密度，并使用图像分析软件进行分析。我们还使用 DNA/CD63 免疫荧光染色和一种荧光标记的 RNA 分子探针来检测人血嗜酸性粒细胞分泌颗粒中 DNA 和 RNA 的存在。
血液和骨髓嗜酸性粒细胞分泌颗粒中溴脱氧尿苷标记的 DNA 和溴尿嘧啶标记的 RNA 免疫电镜金颗粒的平均密度明显高于细胞质或背景染色（p<0.0005）。我们还通过免疫荧光染色和荧光标记的 RNA 分子探针证明了人外周血嗜酸性粒细胞的 CD63 阳性分泌颗粒中存在 DNA 和 RNA。
这些结果提供了证据表明，嗜酸性粒细胞颗粒是 DNA 和 RNA 合成的场所，并提示了嗜酸性粒细胞分泌颗粒可能具有新的作用。
