Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
Centre de Recherche en Transplantation et Immunologie UMR 1064, INSERM, Université de Nantes, Nantes, France.
Front Immunol. 2019 May 10;10:1060. doi: 10.3389/fimmu.2019.01060. eCollection 2019.
Dendritic cell activating receptor-1 (DCAR1) is a cell-surface receptor encoded by the Antigen Presenting Lectin-like gene Complex (APLEC). We generated a mouse monoclonal antibody against rat DCAR1, and used this to characterize receptor expression and function. Rat DCAR1 was expressed on minor subsets of myeloid cells in lymphoid tissue, but was uniformly expressed at a high level by eosinophils, and at a low level by neutrophils. It was expressed by eosinophils in the peritoneal cavity and the lamina propria of the gut, and by subsets of macrophages or dendritic cells at these sites. Polarization of peritoneal macrophages showed that DCAR1 expression was absent on M1 macrophages, and increased on M2 macrophages. DCAR1 could be expressed as a homodimer and its associated with the activating adaptor protein FcεRIγ. This association allowed efficient phagocytosis of antibody-coated beads. Additionally, cross-linking of DCAR1 on the surface of rat eosinophils lead to production of reactive oxygen species. These data show that DCAR1 is an activating receptor. Its expression on M2 macrophages and eosinophils suggests that it may play a role in the immune response to parasites.
树突状细胞激活受体-1（DCAR1）是由抗原呈递凝集素样基因复合物（APLEC）编码的细胞表面受体。我们生成了一种针对大鼠 DCAR1 的小鼠单克隆抗体，并利用该抗体来鉴定受体的表达和功能。大鼠 DCAR1 表达在淋巴组织中髓样细胞的少数亚群上，但在嗜酸性粒细胞中高水平表达，在中性粒细胞中低水平表达。它在腹腔和肠道固有层中的嗜酸性粒细胞中表达，并在这些部位的巨噬细胞或树突状细胞亚群中表达。腹腔巨噬细胞的极化表明，M1 巨噬细胞上没有 DCAR1 的表达，而 M2 巨噬细胞上的表达增加。DCAR1 可以作为同源二聚体表达，并与激活衔接蛋白 FcεRIγ 相关联。这种关联允许抗体包被的珠粒的有效吞噬作用。此外，大鼠嗜酸性粒细胞表面的 DCAR1 交联导致活性氧物质的产生。这些数据表明，DCAR1 是一种激活受体。它在 M2 巨噬细胞和嗜酸性粒细胞上的表达表明，它可能在寄生虫免疫反应中发挥作用。
