S19 ribosomal protein cross-linked dimer causes monocyte-predominant infiltration by means of molecular mimicry to complement C5a.
S19 ribosomal protein cross-linked dimer causes monocyte-predominant infiltration by means of molecular mimicry to complement C5a.
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S19核糖体蛋白交联二聚体通过分子模拟的方式引起单核细胞为主的浸润以补充C5a。
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
Tetsuro Yamamoto
中科院分区：
文献类型：
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作者：
Hiroshi Nishiura;Y. Shibuya;Tetsuro Yamamoto
S19核糖体蛋白是蛋白质生产机器核糖体的组成部分。当重组S19蛋白通过血浆转氨酶（凝血因子XIIIa）分子间交联时，这种同源二聚体新表现出单核细胞趋化活性。这种效应对单核细胞是特异性的。S19蛋白同源二聚体与补体衍生趋化因子组分5a（C5 a）具有相同的免疫反应性。用抗C5 a受体抗体或用合成的C5 a受体拮抗剂预处理的单核细胞对该同二聚体的趋化性反应较差。这些数据表明，S19蛋白同源二聚体具有与C5 a在免疫表位和受体配体方面相似的三维结构，尽管它们的一级结构之间的同源性仅为4%。相反，S19蛋白同源二聚体不吸引多形核白细胞。此外，同二聚体抑制多形核白细胞的趋化反应C5 a在体外和体内作为受体拮抗剂。此外，S19蛋白同二聚体竞争性抑制放射性标记的C5 a与多形核白细胞的结合。S19蛋白同二聚体在白细胞趋化性中具有这些相反的作用，似乎在慢性炎症中诱导单核细胞/巨噬细胞占主导地位的浸润。
S19 ribosomal protein is a component of the protein-producing machinery, ribosome. When recombinant S19 proteins were cross-linked intermolecularly by plasma transglutaminase (coagulation factor XIIIa), this homodimer newly exhibited monocyte chemotactic activity. This effect was specific to monocytes. The S19 protein homodimer shared the immunoreactivity with the complement-derived chemotactic factor, component 5a (C5a). Monocytes pretreated with an anti-C5a receptor antibody or with a synthetic C5a receptor antagonist responded poorly in chemotaxis to this homodimer. These data indicate that the S19 protein homodimer possesses a 3-dimensional structure similar to C5a in terms of the immunologic epitope and the receptor ligand, although homology between their primary structures is only 4%. In contrast, the S19 protein homodimer did not attract polymorphonuclear leukocytes. In addition, the homodimer inhibited a chemotactic response of polymorphonuclear leukocytes to C5a in vitro and in vivo as a receptor antagonist. Furthermore, the S19 protein homodimer competitively inhibited the binding of radiolabeled C5a to polymorphonuclear leukocytes. The S19 protein homodimer with these opposite effects in the leukocyte chemotaxis seems to induce the monocyte/macrophage predominant infiltration in chronic inflammation.