Mahnke K, Becher E, Ricciardi-Castagnoli P, Luger T A, Schwarz T, Grabbe S
Ludwig Boltzmann Institute for Cell Biology and Immunobiology of the Skin, Department of Dermatology, University of Münster, Germany.
Adv Exp Med Biol. 1997;417:145-59. doi: 10.1007/978-1-4757-9966-8_25.
The CD14 surface molecule is predominantly expressed by cells of myeloid origin and regarded as a specific marker for macrophages (M phi). Thus, in human mononuclear cell preparations, CD14 expression is a widely used parameter to distinguish M phi from dendritic cells (DC). Since a murine homologue of CD14 was recently identified, this study investigated expression of CD14 by murine M phi and DC. Flow cytometry with a monoclonal antibody directed against murine CD14 revealed that bone marrow-derived DC express CD14 to various extents during differentiation. Functionally, CD14high and CD14low DC did not differ significantly in their capacity to present alloantigen, protein antigen or immunogenic peptide. Furthermore, surface expression of CD14 could be modulated by interleukin (IL)-4 and LPS. Incubation of bone marrow-derived DC with IL-4 (100 U/ml) resulted in downregulation of CD14 surface expression, whereas exposure of BmDC to LPS (1 microgram/ml) led to upregulation of CD14. After blockage of CD14 molecules by incubation of DC with anti-CD14 antibodies, downregulation of LPS triggered IL-1 release could be detected. In addition, other M phi markers such as CD11b, F4/80, BM8, and ER-TR9, are also expressed on DC. Therefore, we conclude that CD14, like other M phi markers, is expressed on murine DC during maturation. Thus, M phi and DC cannot be distinguished by flow cytometry using these markers. Moreover, CD14 may be involved in mediating LPS-induced activation of murine DC.
CD14表面分子主要由髓系来源的细胞表达，被视为巨噬细胞（M phi）的特异性标志物。因此，在人单核细胞制剂中，CD14表达是区分M phi与树突状细胞（DC）的广泛使用的参数。由于最近鉴定出了CD14的鼠同源物，本研究调查了鼠M phi和DC中CD14的表达。用针对鼠CD14的单克隆抗体进行流式细胞术分析显示，骨髓来源的DC在分化过程中不同程度地表达CD14。在功能上，CD14高表达和低表达的DC在呈递同种异体抗原、蛋白质抗原或免疫原性肽的能力上没有显著差异。此外，CD14的表面表达可被白细胞介素（IL）-4和脂多糖（LPS）调节。用IL-4（100 U/ml）孵育骨髓来源的DC导致CD14表面表达下调，而将骨髓来源的DC暴露于LPS（1微克/毫升）导致CD14上调。在用抗CD14抗体孵育DC阻断CD14分子后，可检测到LPS触发的IL-1释放下调。此外，其他M phi标志物如CD11b、F4/80、BM8和ER-TR9也在DC上表达。因此，我们得出结论，CD14与其他M phi标志物一样，在鼠DC成熟过程中表达。因此，不能使用这些标志物通过流式细胞术区分M phi和DC。此外，CD14可能参与介导LPS诱导的鼠DC活化。
