Department of Veterans Affairs Medical Center, VA Medical Center/Research Service, 1310 24th Ave,, South, Nashville TN 37212, USA.
BMC Immunol. 2012 Sep 12;13:51. doi: 10.1186/1471-2172-13-51.
The mannose receptor is the best described member of the type I transmembrane C-type lectins; however much remains unanswered about the biology of the receptor. One difficulty has been the inability to consistently express high levels of a functional full length mannose receptor cDNA in mammalian cells. Another difficulty has been the lack of a human macrophage cell line expressing a fully functional receptor. Commonly used human macrophage cell lines such as U937, THP-1, Mono-Mac and HL60 do not express the mannose receptor. We have developed a macrophage hybridoma cell line (43MR cells) created by fusion of U937 cells with primary human monocyte-derived macrophages, resulting in a non-adherent cell line expressing several properties of primary macrophages. The purpose of this study was to identify and select mannose receptor-expressing cells using fluorescence-activated cell sorting and to characterize the expression and function of the receptor.
In the current study we show that the mannose receptor found on this novel cell has endocytic characteristics consistent with and similar to the mannose receptor found on the surface of monocyte-derived human macrophages and rat bone marrow-derived macrophages. In addition, we demonstrate that these cells engage and internalize pathogen particles such as S. aureus and C. albicans. We further establish the transfectability of these cells via the introduction of a plasmid expressing influenza A hemagglutinin.
The 43MR cell line represents the first naturally expressed MR-positive cell line derived from a human macrophage background. This cell line provides an important cell model for other researchers for the study of human MR biology and host-pathogen interactions.
甘露糖受体是 I 型跨膜 C 型凝集素中描述得最好的成员；然而，关于该受体的生物学仍有许多未解之谜。其中一个困难是，无法在哺乳动物细胞中始终如一地表达高水平的功能性全长甘露糖受体 cDNA。另一个困难是缺乏表达完全功能性受体的人巨噬细胞系。常用的人巨噬细胞系，如 U937、THP-1、Mono-Mac 和 HL60，并不表达甘露糖受体。我们已经开发了一种巨噬细胞杂交瘤细胞系（43MR 细胞），该细胞系是通过 U937 细胞与原代人单核细胞衍生的巨噬细胞融合而成的，产生了一种非贴壁细胞系，表达了原代巨噬细胞的几种特性。本研究的目的是使用荧光激活细胞分选来鉴定和选择表达甘露糖受体的细胞，并表征受体的表达和功能。
在本研究中，我们表明，这种新型细胞上发现的甘露糖受体具有与单核细胞衍生的人巨噬细胞和大鼠骨髓衍生的巨噬细胞表面发现的甘露糖受体一致的内吞特性。此外，我们证明这些细胞能够结合并内化病原体颗粒，如金黄色葡萄球菌和白色念珠菌。我们进一步通过引入表达流感 A 血凝素的质粒来证明这些细胞的可转染性。
43MR 细胞系代表了第一个源自人巨噬细胞背景的天然表达 MR 阳性细胞系。该细胞系为其他研究人员研究人类 MR 生物学和宿主-病原体相互作用提供了重要的细胞模型。
