Mortezagholi Sahar, Mahmoudi Ahmad-Reza, Shojaeian Sorour, Vafaei Sedigheh, Soltanghoraei Haleh, Bayat Ali-Ahmad, Shokri Fazel, Ghods Roya, Zarnani Amir-Hassan
Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.
Cell Tissue Res. 2023 Oct;394(1):177-188. doi: 10.1007/s00441-023-03817-y. Epub 2023 Aug 3.
Here, retrotransposon-like 1 (RTL1) is introduced as a marker for circulating and tissue neutrophils, tissue macrophages, and tumor-associated macrophages (TAM) and neutrophils (TAN). Anti-RTL1 polyclonal and monoclonal antibodies were produced, and their reactivity was examined by Western blotting (WB), ELISA, and immunostaining of human normal and cancer tissues. The reactivity of the anti-RTL1 antibodies with peripheral blood leukocytes and a panel of hematopoietic cell lines was examined. The generated antibodies specifically detected RTL1 in the WB of the placenta and U937 cells. The polyclonal antibody showed excellent reactivity with tissue-resident macrophages, Hofbauer cells, alveolar and splenic macrophages, Kupffer cells, and inflammatory cells in the tonsil, appendix, and gallbladder. In vitro GM-CSF-differentiated macrophages also showed a high level of intracellular RTL1 expression. TAM and TAN also showed excellent reactivity with this antibody. Almost all circulating granulocytes but not lymphocytes or monocytes expressed RTL1 at their surface. Serial sections of the appendix stained with CD15 and RTL1 and placenta stained with CD68 and RTL1 showed a considerable overlap in RTL1 expression in CD15 granulocytes and CD68 macrophages. A small percentage of myelomonocytic cell lines was positive for surface RTL1, while promyelocytic, monocytic, megaloblastic, and lymphoblastic cell lines were negative. Endothelial cells of normal and cancer tissues highly expressed RTL1. RTL1 could be considered a new marker for different normal tissue macrophages, TAM, circulating and tissue neutrophils, and TAN.
在此，逆转录转座子样1（RTL1）被引入作为循环和组织中性粒细胞、组织巨噬细胞以及肿瘤相关巨噬细胞（TAM）和中性粒细胞（TAN）的标志物。制备了抗RTL1多克隆抗体和单克隆抗体，并通过蛋白质免疫印迹法（WB）、酶联免疫吸附测定（ELISA）以及对人正常组织和癌组织进行免疫染色来检测它们的反应性。检测了抗RTL1抗体与外周血白细胞及一组造血细胞系的反应性。所产生的抗体在胎盘和U937细胞的WB中能特异性检测到RTL1。多克隆抗体与组织驻留巨噬细胞、霍夫鲍尔细胞、肺泡巨噬细胞、脾巨噬细胞、库普弗细胞以及扁桃体、阑尾和胆囊中的炎性细胞表现出良好的反应性。体外经粒细胞-巨噬细胞集落刺激因子（GM-CSF）分化的巨噬细胞也显示出高水平的细胞内RTL1表达。TAM和TAN与该抗体也表现出良好的反应性。几乎所有循环粒细胞而非淋巴细胞或单核细胞在其表面表达RTL1。用CD15和RTL1染色的阑尾连续切片以及用CD68和RTL1染色的胎盘显示，CD15粒细胞和CD68巨噬细胞中RTL1表达有相当程度的重叠。一小部分骨髓单核细胞系表面RTL1呈阳性，而早幼粒细胞系、单核细胞系、巨幼细胞系和淋巴细胞系呈阴性。正常组织和癌组织的内皮细胞高度表达RTL1。RTL1可被视为不同正常组织巨噬细胞、TAM、循环和组织中性粒细胞以及TAN的一种新标志物。
