Hughes D A, Fraser I P, Gordon S
Sir William Dunn School of Pathology, Oxford.
Eur J Immunol. 1995 Feb;25(2):466-73. doi: 10.1002/eji.1830250224.
Macrophage scavenger receptors are trimeric integral membrane glycoproteins which have been implicated in various macrophage functions including uptake of oxidized lipoprotein and the serum-dependent, divalent cation-independent adhesion of macrophages to tissue culture-treated plastic. In this study we have used a recently defined monoclonal antibody (2F8) which recognizes murine macrophage scavenger receptor, to explore its expression in lymphoid and non-lymphoid organs of the normal adult. Scavenger receptor was detected in the red pulp and marginal zone of normal adult mouse spleen, medulla of the thymus and subcapsular region of lymph nodes. Kupffer cells in the liver, alveolar macrophages in the lung and lamina propria macrophages in the gut all reacted with 2F8 monoclonal antibody. The antigen was not detected on any non-macrophage cells, with the exception of sinusoidal endothelial cells in the liver. In the spleen, lymph node and liver, scavenger receptor antigen expression was associated specifically with phagocytic cells which had taken up colloidal carbon. To examine macrophage adhesion in a context relevant to the interactions occurring within lymphoid and non-lymphoid organs, and the contribution of macrophage scavenger receptor to this adhesion, we designed an assay of macrophage adhesion to frozen tissue sections. Adhesion to most tissues was high and uniform in the absence of any chelating agents. The chelation of Ca2+ and Mg2+ revealed specific patterns of macrophage adhesion in lymphoid and non-lymphoid organs which was completely inhibited by 2F8. The ability of this antibody to block the EDTA-resistant adhesion correlated with tissue expression of the antigen in some tissues. Unlike adhesion to tissue culture-treated plastic, macrophage scavenger receptor-dependent adhesion of macrophages to frozen tissue sections did not exhibit an absolute requirement for exogenous fetal bovine serum indicating the presence of an endogenous ligand for scavenger receptor within the tissues. We propose that macrophage scavenger receptor is a candidate homing or retention molecule for macrophage localization within ligand-rich tissues.
巨噬细胞清道夫受体是三聚体整合膜糖蛋白，与多种巨噬细胞功能有关，包括摄取氧化脂蛋白以及巨噬细胞对经组织培养处理的塑料的血清依赖性、二价阳离子非依赖性黏附。在本研究中，我们使用了一种最近鉴定的识别小鼠巨噬细胞清道夫受体的单克隆抗体（2F8），以探究其在正常成年动物淋巴器官和非淋巴器官中的表达情况。在正常成年小鼠脾脏的红髓和边缘区、胸腺髓质以及淋巴结的被膜下区域检测到了清道夫受体。肝脏中的库普弗细胞、肺中的肺泡巨噬细胞以及肠道固有层巨噬细胞均与2F8单克隆抗体发生反应。除肝脏的窦状内皮细胞外，在任何非巨噬细胞上均未检测到该抗原。在脾脏、淋巴结和肝脏中，清道夫受体抗原表达与摄取了胶体碳的吞噬细胞特异性相关。为了在与淋巴器官和非淋巴器官内发生的相互作用相关的背景下研究巨噬细胞黏附以及巨噬细胞清道夫受体对这种黏附的作用，我们设计了一种巨噬细胞对冷冻组织切片黏附的检测方法。在没有任何螯合剂的情况下，对大多数组织的黏附率高且均匀。Ca2+和Mg2+的螯合揭示了淋巴器官和非淋巴器官中巨噬细胞黏附的特定模式，而这种模式被2F8完全抑制。该抗体阻断EDTA抗性黏附的能力与某些组织中抗原的组织表达相关。与对经组织培养处理的塑料的黏附不同，巨噬细胞对冷冻组织切片的清道夫受体依赖性黏附对外源胎牛血清没有绝对需求，这表明组织内存在清道夫受体的内源性配体。我们提出巨噬细胞清道夫受体是巨噬细胞在富含配体组织中定位的归巢或滞留分子的候选者。
