The human C3b receptor: function and role in human diseases.
The human C3b receptor: function and role in human diseases.
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人类 C3b 受体：在人类疾病中的功能和作用。
DOI：
10.1111/1523-1747.ep12876125
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Gigli,I
中科院分区：
文献类型：
--
作者：
Tausk,F;Gigli,I
人C3 b受体（CR 1）是一种多态性糖蛋白，其通过抑制C3和CS的活化来调节补体系统，通过其对它们的转化酶的作用，并作为因子I的辅因子介导C3 b降解为其无活性片段C3 bi并进一步降解为C3 d-g。后者则是白细胞上各自受体CR 3和CR2的配体。此外，红细胞上的CR 1赋予这些细胞将免疫复合物（IC）递送至网状内皮系统的能力，导致其从循环中清除。在吞噬细胞上，这种受体参与外来颗粒的内吞过程。不同个体红细胞CR 1表达（CR 1/E）存在广泛的遗传差异。患有IC水平升高的疾病的患者，如系统性红斑狼疮、麻风病和艾滋病，其CR 1/E显著降低，这可能导致清除率改变。这种减少似乎与疾病活动有关，CR 1/E损失的最可能部位是IC转移到巨噬细胞期间。健康的中性粒细胞对趋化肽的反应使其CR 1的表达增加十倍。艾滋病患者的中性粒细胞显示出对刺激的反应改变。这种缺陷可能与内吞作用有关。
The human C3b receptor (CR1) is a polymorphic glycoprotein which functions regulating the complement system by inhibiting the activation of C3 and CS, through its effect on their convertases, and serving as cofactor for factor I in mediating the degradation of C3b to its inactive fragment C3bi and further to C3d-g. The latter are then ligands for their respective receptors on leukocytes, CR3 and CR2. Additionally, CR1 on erythrocytes endows these cells with the capacity to deliver immune complexes (IC) to the reticuloendothelial system, resulting in their clearance from the circulation. On phagocytes, this receptor participates in the process of endocytosis of foreign particles. There is a wide inherited variation of CR1 expression on erythrocytes (CR1/E) of different individuals. Patients with diseases which feature elevated levels of IC, such as systemic lupus erythematosus, leprosy, and AIDS, have a marked decrease of CR1/E, which may result in an altered clearance. This reduction appears to be related to disease activity, and the most probable site for CR1/E loss is during the transfer of IC to macrophages. Healthy neutrophils increase tenfold their expression of CR1 in response to the effect of chemoattractant peptides. Neutrophils from patients with AIDS display an altered response to stimulation. This defect may be of relevance in the process of endocytosis.