Crocker P R, Freeman S, Gordon S, Kelm S
Imperial Cancer Research Fund Laboratories, University of Oxford, John Radcliffe Hospital, United Kingdom.
J Clin Invest. 1995 Feb;95(2):635-43. doi: 10.1172/JCI117708.
Sialoadhesin is a macrophage-restricted, sialic acid-dependent receptor of 185 kD that binds to the oligosaccharide sequence NeuAc alpha 2,3Gal on cell surface glycoconjugates. Recent cDNA cloning has shown that sialoadhesin is a new member of the immunoglobulin superfamily with sequence similarity to CD22, a sialic acid-dependent receptor of B lymphocytes. Sialoadhesin has been implicated in cellular interactions of stromal macrophages with developing myeloid cells. In this study, direct evidence for this interaction was obtained in cell-cell binding assays using both native and recombinant forms of the protein. In all assays, sialoadhesin exhibited specific, differential binding to various murine cell populations of hemopoietic origin. In rank order, sialoadhesin bound neutrophils > bone marrow cells = blood leukocytes > lymphocytes > thymocytes. Single-cell analyses confirmed that sialoadhesin selectively bound myeloid cells in complex cell mixtures obtained from the bone marrow and blood. In comparison, a recombinant Fc-chimeric form of murine CD22 showed high binding to B and T lymphocytes, but very low binding to immature and mature myeloid cells. These results are consistent with the notion that sialoadhesin in involved in interactions with granulocytes at different stages of their life histories.
唾液酸黏附素是一种仅在巨噬细胞表达的、依赖唾液酸的185kD受体，它能与细胞表面糖缀合物上的寡糖序列NeuAcα2,3Gal结合。最近的cDNA克隆研究表明，唾液酸黏附素是免疫球蛋白超家族的一个新成员，其序列与B淋巴细胞的唾液酸依赖性受体CD22相似。唾液酸黏附素参与了基质巨噬细胞与发育中的髓样细胞之间的细胞相互作用。在本研究中，通过使用天然和重组形式的蛋白质进行细胞间结合试验，获得了这种相互作用的直接证据。在所有试验中，唾液酸黏附素对各种造血来源的小鼠细胞群体表现出特异性的、差异性的结合。按结合程度排序，唾液酸黏附素与中性粒细胞的结合能力大于骨髓细胞=血液白细胞>淋巴细胞>胸腺细胞。单细胞分析证实，唾液酸黏附素在从骨髓和血液中获得的复杂细胞混合物中选择性地结合髓样细胞。相比之下，小鼠CD22的重组Fc嵌合形式对B和T淋巴细胞有高结合能力，但对未成熟和成熟髓样细胞的结合能力非常低。这些结果与唾液酸黏附素参与粒细胞在其生命历程不同阶段相互作用的观点一致。
