Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA.
J Immunol. 2011 Oct 1;187(7):3483-7. doi: 10.4049/jimmunol.1101549. Epub 2011 Aug 24.
Reportedly, CD300f negatively regulates interactions between dendritic and T cells and acts as an anti-inflammatory molecule in a multiple sclerosis mouse model. We found that a CD300f/Fc chimeric protein specifically binds to apoptotic/dead splenocytes and to apoptotic cells from starved or irradiated lymphocytic cell lines, an observation extended to insect cells. CD300f also binds PMA/ionomycin-activated splenocytes and Ag-stimulated T cells, an interaction inhibited by Annexin V. By ELISA, cosedimentation, and surface plasmon resonance using phospholipid-containing liposomes, we show that CD300f preferentially binds phosphatidylserine and requires a metal ion. Exogenous expression of CD300f in cell lines results in enhanced phagocytosis of apoptotic cells. We conclude that expression of CD300f conveys additional capacity to recognize phosphatidylserine to myeloid cells. The result of this recognition may vary with the overall qualitative and quantitative receptor content, as well as signaling capacity of the expressing effector cell, but enhanced phagocytosis is one measurable outcome.
据报道，CD300f 负调节树突状细胞与 T 细胞之间的相互作用，并在多发性硬化症小鼠模型中作为抗炎分子发挥作用。我们发现，CD300f/Fc 嵌合蛋白特异性结合凋亡/死亡的脾细胞，以及饥饿或辐照的淋巴细胞系中的凋亡细胞，这一观察结果扩展到了昆虫细胞。CD300f 还结合 PMA/离子霉素激活的脾细胞和 Ag 刺激的 T 细胞，这种相互作用被 Annexin V 抑制。通过 ELISA、共沉淀和使用含有磷脂的脂质体的表面等离子体共振，我们表明 CD300f 优先结合磷脂酰丝氨酸并需要金属离子。在细胞系中外源性表达 CD300f 导致对凋亡细胞的吞噬作用增强。我们得出结论，CD300f 的表达赋予髓样细胞识别磷脂酰丝氨酸的额外能力。这种识别的结果可能因表达效应细胞的整体定性和定量受体含量以及信号转导能力而异，但增强的吞噬作用是一个可衡量的结果。
