Golden-Mason L, Kelly A M, Traynor O, McEntee G, Kelly J, Hegarty J E, O'Farrelly C
Education & Research Centre, St. Vincent's University Hospital, Dublin, Ireland.
Cytokine. 2001 May 7;14(3):143-51. doi: 10.1006/cyto.2001.0852.
Interleukin-7 (IL-7) has been shown to play an essential role in T-cell development. Recombinase-activating gene (RAG)-1, RAG-2 and pre-TCR-alpha expression in the normal adult human liver (AHL), together with the presence of lymphoid-haematopoietic progenitors, is strong evidence that the AHL supports T cell maturation. We investigated IL-7 mRNA and protein levels in order to determine whether AHL could support T lymphocyte differentiation. Biopsies were snap frozen, powdered, and RNA/protein extracted. Reverse transcriptase polymerase chain reaction was used to detect IL-7 using primers that amplified 620 base pair (bp) fragments and other smaller transcripts. A sandwich enzyme-linked immunosorbent assay was developed to quantify IL-7 protein in homogenates. The anatomic distribution of IL-7-secreting cells was determined by immunohistochemistry. IL-7-specific product (620 bp) was detected in nine of ten samples, with six also positive for a smaller splice-variant (488 bp). Levels of the 620 bp product were 2.5 times greater than the 488 bp fragment. IL-7 protein was detected in all samples (range 18.47-76.93 pg/100 mg tissue). Immunohistochemistry demonstrated IL-7 protein in discrete cells of lymphoid morphology, widely distributed throughout the parenchyma and within portal tracts. Large populations of innate T cells are found in normal AHL, some of which may differentiate locally. The presence of IL-7 RNA and protein throughout normal hepatic tissue provides evidence that the normal AHL is a suitable microenvironment for T cell differentiation.
白细胞介素-7（IL-7）已被证明在T细胞发育中起关键作用。正常成人肝脏（AHL）中重组激活基因（RAG）-1、RAG-2和前T细胞受体α（pre-TCR-α）的表达，以及淋巴造血祖细胞的存在，有力地证明了AHL支持T细胞成熟。我们研究了IL-7的mRNA和蛋白水平，以确定AHL是否能支持T淋巴细胞分化。活检组织经速冻、研磨成粉后提取RNA/蛋白。使用能扩增620个碱基对（bp）片段及其他较小转录本的引物，通过逆转录聚合酶链反应检测IL-7。开发了一种夹心酶联免疫吸附测定法来定量匀浆中的IL-7蛋白。通过免疫组织化学确定分泌IL-7细胞的解剖分布。在十个样本中的九个样本中检测到了IL-7特异性产物（620 bp），其中六个样本对一个较小的剪接变体（488 bp）也呈阳性。620 bp产物的水平比488 bp片段高2.5倍。在所有样本中均检测到IL-7蛋白（范围为18.47 - 76.93 pg/100 mg组织）。免疫组织化学显示，在整个实质和门管区内广泛分布的具有淋巴细胞形态的离散细胞中存在IL-7蛋白。在正常AHL中发现大量先天性T细胞，其中一些可能在局部发生分化。正常肝组织中存在IL-7 RNA和蛋白，这证明正常AHL是T细胞分化的合适微环境。
