FIBRONECTIN-MEDIATED BINDING AND PHAGOCYTOSIS OF POLYSTYRENE LATEX BEADS BY BABY HAMSTER-KIDNEY CELLS
FIBRONECTIN-MEDIATED BINDING AND PHAGOCYTOSIS OF POLYSTYRENE LATEX BEADS BY BABY HAMSTER-KIDNEY CELLS
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DOI：
10.1083/jcb.97.5.1515
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发表时间：
1983-01-01
影响因子：
7.8
通讯作者：
GRINNELL, F
中科院分区：
文献类型：
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作者：
MCABEE, DD;GRINNELL, F
研究了纤维连接蛋白（pFN）包被的乳胶珠与幼仓鼠肾（BHK）细胞的结合和吞噬作用，结果表明，乳胶珠的结合和吞噬作用与纤维连接蛋白浓度和乳胶珠直径有关。将细胞与放射性pFN包被的珠一起孵育，并将总珠结合（摄入的细胞表面）测量为与细胞相关的总放射性。在结合的珠粒中，那些也被吞噬的珠粒的区别在于它们对通过胰蛋白酶处理从细胞释放的不敏感性。在连续温育中，pFN包被的珠与细胞的结合发生在4 ℃。C或37 ° C。C，但仅在37 ℃下观察到吞噬作用。C.此外，3H-pFN从摄入的珠粒中的降解发生在37 ℃。C，如三氯乙酸可溶性放射性释放到孵育培养基中所示。当珠上的纤连蛋白密度变化时，在4 ° C下结合。在37 ℃下，发现C具有相同的剂量-反应依赖性，这表明允许珠结合的pFN密度足以发生吞噬作用。摄取的最大结合的纤连蛋白密度为. apprx。250 ng pFN/cm 2。当用类似密度的pFN包被的各种大小的珠（0.085 - 1.091 μ m）与细胞在4 ℃温育时，C，未观察到结合随珠粒尺寸的变化。在这些条件下，pFN的绝对量在1.091 μ m珠上的15，000个分子的范围内。< 100 molecules on the 0.085-.mu.m beads to >控制BHK细胞对乳胶珠的纤连蛋白介导的结合的关键参数是珠上pFN分子的间距。对于发生多价相互作用而言最佳的细胞表面上的pFN受体之间的间距为18 nM。当比较各种大小的珠粒的吞噬作用时，发现最大的珠粒比最小的珠粒吞噬作用稍好（2倍）。这发生在细胞与珠子的连续孵育中以及珠子与细胞预结合时。分析0.085 μ M pFN包被的珠与细胞结合的动力学常数。似乎有. apprx。62，000个结合位点，Kd为4.03 × 106。10-9 M.假设二价相互作用，计算出BHK细胞具有120，000个pFN受体/细胞，pFN与其受体之间的结合亲和力为apx。6倍。10-5 M.
The binding and phagocytosis of fibronectin (pFN)-coated latex beads by baby hamster kidney (BHK) cells was studied as a function of fibronectin concentration and bead diameter. Cells were incubated with radioactive pFN-coated beads, and total bead binding (cell surface of ingested) was measured as total radioactivity associated with the cells. Of the bound beads, those that also were phagocytosed were distinguished by their insensitivity to release from the cells by trypsin treatment. In continuous incubations, binding of pFN-coated beads to cells occurred at 4.degree. C or 37.degree. C, but phagocytosis was observed only at 37.degree. C. In addition, degradation of 3H-pFN from ingested beads occurred at 37.degree. C, as shown by the release of trichloroacetic acid-soluble radioactivity into the incubation medium. When the fibronectin density on the beads was varied, binding at 4.degree. C and ingestion at 37.degree. C were found to have the same dose-response dependencies, which indicated that pFN densities that permitted bead binding were sufficient for phagocytosis to occur. The fibronectin density for maximal binding of ingestion was .apprx. 250 ng pFN/cm2. When various sized beads (0.085-1.091 .mu.m), coated with similar densities of pFN, were incubated with cells at 4.degree. C, no variation in binding as a function of bead size was observed. Under these conditions, the absolute amount of pFN ranged from < 100 molecules on the 0.085-.mu.m beads to > 15,000 molecules on the 1.091-.mu.m beads. The critical parameter controlling fibronectin-mediated binding of latex beads by BHK cells is the spacing of the pFN molecules on the beads. The spacing between pFN receptors on the cell surface that is optimal for multivalent interactions to occur is .apprx. 18 nM. When phagocytosis of various sized beads was compared, it was found that the largest beads were phagocytosed slightly better (2-fold) than the smallest beads. This occurred both in continuous incubations of cells with beads and when the beads were prebound to the cells. The kinetic constants for the binding of 0.085 .mu.M pFN-coated beads to the cells were analyzed. There appeared to be .apprx. 62,000 binding sites and the Kd was 4.03 .times. 10-9 M. Assuming bivalent interaction, it was calculated that BHK cells have .apprx. 120,000 pFN receptors/cell and the binding affinity between pFN and its receptor is .apprx. 6 .times. 10-5 M.