Isolation and characterization of beta-glucan receptors on human mononuclear phagocytes.
Isolation and characterization of beta-glucan receptors on human mononuclear phagocytes.
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DOI：
10.1084/jem.173.6.1511
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发表时间：
1991-06-01
期刊：
影响因子：
--
通讯作者：
Kay J
中科院分区：
文献类型：
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作者：
Czop JK;Kay J
对酵母和真菌碳水化合物聚合物具有配体特异性的β-葡聚糖受体已被研究为人单核细胞的吞噬受体。为了表征其结构，使用人U937细胞和识别单核细胞β-葡聚糖受体表位的兔IgG抗Id进行了结合研究。未刺激的U937细胞特异性结合大量的抗Id，但几乎没有对照抗同种型。饱和时，每个U937细胞结合的抗Id分子数为2.6 x 10（6），表观Ka为1.9 x 10（7）M-1。来自表面放射性碘标记的U937细胞的去污剂裂解物的免疫沉淀物仅含有两种对抗Id具有抗原特异性的膜蛋白，一种具有180 kD的分子量，另一种具有160 kD的分子量。这两种蛋白质的二硫键连接，并提出，减少后，作为五个多肽的95，88，60，27，和20 kD。未标记的U937细胞的洗涤剂裂解物，通过亲和层析纯化的抗Id-琼脂糖凝胶，产生了相同的两个非还原蛋白质和5个还原产物的板凝胶染色考马斯蓝。在用抗Id探测的Western印迹中，最具免疫反应性的非还原和还原亲和纯化产物分别为160和20 kD分子。二维凝胶的免疫印迹显示180和160 kD蛋白通过与20 kD多肽的二硫键连接表达共同的表位。通过免疫印迹分析，U937细胞葡聚糖结合蛋白从洗涤剂裂解物中含有两个细胞蛋白抗原的抗Id是无法区分的亲和纯化的分子的大小和亚基组成。通过免疫印迹分析对去污剂溶解的人单核细胞亲和纯化蛋白进行了研究，发现其与U937细胞β-葡聚糖受体相同。它们由两个二硫键连接的蛋白质组成，分子量为180和160 kD，并且与抗Id表位共同具有20 kD多肽。
beta-glucan receptors, with ligand specificity for yeast and fungal carbohydrate polymers, have been studied as phagocytic receptors of human monocytes. To characterize their structure, binding studies were carried out with human U937 cells and a rabbit IgG anti-Id that recognizes epitopes on monocyte beta-glucan receptors. Unstimulated U937 cells specifically bound large amounts of the anti-Id, but almost none of the control anti-isotype. At saturation, the number of anti-Id molecules bound per U937 cell was 2.6 x 10(6) with an apparent Ka of 1.9 x 10(7) M-1. Immunoprecipitates from detergent lysates of surface- radioiodinated U937 cells contained only two membrane proteins with antigenic specificity for the anti-Id, one having a mol wt of 180 kD and the other 160 kD. Both proteins were disulfide-linked and presented, after reduction, as five polypeptides of 95, 88, 60, 27, and 20 kD. Detergent lysates of unlabeled U937 cells, purified by affinity chromatography on anti-Id-Sepharose, yielded the same two nonreduced proteins and five reduction products in slab gels stained with Coomassie blue. In Western blots probed with the anti-Id, the most immunoreactive nonreduced and reduced affinity-purified products were the 160 and 20 kD molecules, respectively. Immunoblots of two- dimensional gels showed the 180 and 160 kD proteins to express a common epitope through disulfide linkage to the 20 kD polypeptide. By immunoblot analysis, U937 cell glucan-binding proteins from detergent lysates contained two cell proteins antigenic for the anti-Id that were indistinguishable from affinity-purified molecules in size and subunit composition. Studies of affinity-purified proteins from detergent lysed human monocytes were characterized by immunoblot analysis and found to be identical to U937 cell beta-glucan receptors. They consisted of two disulfide-linked proteins, with mol wt of 180 and 160 kD, and had in common a 20 kD polypeptide with the anti-Id epitope.