Crocker P R, Gordon S
J Exp Med. 1986 Dec 1;164(6):1862-75. doi: 10.1084/jem.164.6.1862.
We describe a novel hemagglutinin which is differentially expressed on murine stromal tissue macrophages. Resident bone marrow macrophages (RBMM), which are physically associated with immature, proliferating hematopoietic cells in vivo, formed striking rosettes with unopsonized sheep erythrocytes (E) in vitro, unlike resident peritoneal macrophages (RPM). Binding of E was macrophage (M phi) specific, not accompanied by ingestion and independent of temperature (0-37 degrees C), divalent cations, and the metabolic inhibitors azide and iodoacetate. Pretreatment of RBMM with trypsin prevented rosette formation, but neuraminidase enhanced it. Conversely, binding was virtually abrogated if E were pretreated with neuraminidase, whereas trypsin pretreatment of the ligand resulted in a slight enhancement. The lectin-like nature of the E receptor (SER), with specificity for sialylated glycoconjugates, was consistent with the inhibition of binding we saw with neuraminyllactose or the ganglioside GD1a (50% inhibition at 5-10 mM and 11 microM, respectively). Expression of SER on freshly isolated RBMM was heterogeneous and exhibited a striking inverse correlation with expression of Ia antigens. During cultivation in 10% FCS, levels of SER on RBMM declined with a half-life of approximately 24 h. Other cell surface changes induced by cultivation included a transient increase in expression of Ia antigen and acquisition of Mac-1. To determine whether SER was expressed on other stromal M phi populations, adherent cells were isolated from various tissues by collagenase digestion or lavage. Binding of E was highest on RBMM and lymph node stromal M phi, at intermediate levels on Kupffer cells and splenic stromal M phi, but was low or undetectable on blood monocytes and thymic, peritoneal, pleural, and bronchoalveolar M phi. SER therefore appeared to be expressed on certain M phi populations embedded in solid tissues but was largely absent from M phi recoverable by lavage. Its absence from monocytes implies that SER is acquired by M phi after entering tissues where it may perform adhesive functions. In bone marrow, SER on RBMM could interact with an appropriate sialylated ligand on murine hematopoietic cells, and could influence their rate of growth and differentiation.
我们描述了一种新型血凝素，它在小鼠基质组织巨噬细胞上呈差异表达。驻留骨髓巨噬细胞（RBMM）在体内与未成熟、增殖的造血细胞存在物理关联，与驻留腹膜巨噬细胞（RPM）不同，它在体外能与未调理的绵羊红细胞（E）形成明显的玫瑰花结。E的结合具有巨噬细胞（M phi）特异性，不伴有摄取现象，且与温度（0 - 37摄氏度）、二价阳离子以及代谢抑制剂叠氮化物和碘乙酸盐无关。用胰蛋白酶预处理RBMM可阻止玫瑰花结形成，但神经氨酸酶可增强其形成。相反，如果用神经氨酸酶预处理E，结合几乎被消除，而对配体进行胰蛋白酶预处理则会导致轻微增强。E受体（SER）的凝集素样性质，对唾液酸化糖缀合物具有特异性，这与我们观察到的神经氨酸乳糖或神经节苷脂GD1a对结合的抑制作用一致（分别在5 - 10 mM和11 microM时抑制50%）。新鲜分离的RBMM上SER的表达是异质性的，并且与Ia抗原的表达呈显著负相关。在10%胎牛血清中培养期间，RBMM上SER的水平以约24小时的半衰期下降。培养诱导的其他细胞表面变化包括Ia抗原表达的短暂增加和Mac - 1的获得。为了确定SER是否在其他基质M phi群体上表达，通过胶原酶消化或灌洗从各种组织中分离贴壁细胞。E的结合在RBMM和淋巴结基质M phi上最高，在库普弗细胞和脾基质M phi上处于中等水平，但在血液单核细胞以及胸腺、腹膜、胸膜和支气管肺泡M phi上较低或检测不到。因此，SER似乎在某些嵌入实体组织的M phi群体上表达，但通过灌洗回收的M phi中基本不存在。单核细胞中不存在SER意味着SER是M phi进入组织后获得的，在组织中它可能发挥黏附功能。在骨髓中，RBMM上的SER可与小鼠造血细胞上合适的唾液酸化配体相互作用，并可能影响其生长和分化速率。
