Binding of the Streptococcus gordonii DL1 surface protein Hsa to the host cell membrane glycoproteins CD11b, CD43, and CD50
Binding of the Streptococcus gordonii DL1 surface protein Hsa to the host cell membrane glycoproteins CD11b, CD43, and CD50
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DOI：
10.1128/iai.00238-08
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发表时间：
2008-10-01
影响因子：
3.1
通讯作者：
Konishi, Kiyoshi
中科院分区：
文献类型：
--
作者：
Urano-Tashiro, Yumiko;Yajima, Ayako;Konishi, Kiyoshi
感染性心内膜炎常归因于口腔链球菌。尽管链球菌和吞噬细胞之间的相互作用被认为是非常重要的，但是其发病机制尚不清楚。Hsa是戈登链球菌高度表达的表面成分，具有唾液酸结合活性，可导致体内感染性心内膜炎。在本研究中，我们发现，S。戈登氏菌DL1结合分化成单核细胞、粒细胞和巨噬细胞的HL-60细胞。使用谷胱甘肽S-转移酶（GST）融合到NR2结构域，这是唾液酸结合区的Hsa，我们证实，Hsa NR2结构域也结合分化的HL-60细胞。为了鉴定分化的HL-60细胞表面上的哪些唾液酸糖蛋白是Hsa的受体，通过细菌覆盖和远蛋白质印迹法评估了内在膜蛋白。S.戈登氏菌DL1粘附于100 - 150-kDa的蛋白质，该反应被神经氨酸酶处理消除。这些唾液酸糖蛋白通过GST下拉试验和与每种特异性单克隆抗体的免疫沉淀鉴定为CD 11b、CD 43和CD 50。这些数据表明S. gordonii DL 1 Hsa特异性结合三种糖蛋白作为受体，这种相互作用可能是口腔链球菌感染性心内膜炎的初始细菌结合步骤。
Infective endocarditis is frequently attributed to oral streptococci. The mechanisms of pathogenesis, however, are not well understood, although interaction between streptococci and phagocytes are thought to be very important. A highly expressed surface component of Streptococcus gordonii, Hsa, which has sialic acid-binding activity, contributes to infective endocarditis in vivo. In the present study, we found that S. gordonii DL1 binds to HL-60 cells differentiated into monocytes, granulocytes, and macrophages. Using a glutathione S-transferase (GST) fusion to the NR2 domain, which is the sialic acid-binding region of Hsa, we confirmed that the Hsa NR2 domain also binds to differentiated HL-60 cells. To identify which sialoglycoproteins on the surface of differentiated HL-60 cells are receptors for Hsa, intrinsic membrane proteins were assessed by bacterial overlay and far-Western blotting. S. gordonii DL1 adhered to 100- to 150-kDa proteins, a reaction that was abolished by neuraminidase treatment. These sialoglycoproteins were identified as CD11b, CD43, and CD50 by GST pull-down assay and immunoprecipitation with each specific monoclonal antibody. These data suggest that S. gordonii DL1 Hsa specifically binds to three glycoproteins as receptors and that this interaction may be the initial bacterial binding step in infective endocarditis by oral streptococci.