Bodmer J L, Dean R T
Biosci Rep. 1983 Nov;3(11):1053-61. doi: 10.1007/BF01121032.
We have previously shown that several agents which interfere with binding of ligands to the mannose-glycoprotein receptor on macrophages can inhibit zymosan-induced lysosomal enzyme secretion. Here we show that mannose only reduces the association of zymosan with macrophages during the first hour of exposure; after longer periods of uptake no effect is detectable. We have previously shown that mannose reduces surface binding of zymosan, probably by interfering selectively with binding to the mannose receptor. The present inhibition of association of zymosan with macrophages during short exposures can be entirely explained by this reduction of binding. Macrophages must therefore internalize zymosan at sites in addition to the mannose receptor. In contrast to macrophages the murine macrophage-like cell line P388D1 is lacking the mannose-glycoprotein receptor. Accordingly we find that binding of zymosan to P388D1 is much slighter than to macrophages and is unaffected by mannose or mannose-6-phosphate. The spontaneous lysosomal enzyme secretion of P388D1 is also unaffected by mannose. The data on macrophages confirm our previous suggestion that agents interfering with the mannose receptor inhibit the induction of lysosomal enzyme secretion by acting directly on the receptor. The data on P388D1 cells support this assertion by excluding effects at later steps in the secretory pathway.
我们之前已经表明，几种干扰配体与巨噬细胞上甘露糖 - 糖蛋白受体结合的试剂可以抑制酵母聚糖诱导的溶酶体酶分泌。在此我们表明，甘露糖仅在暴露的第一个小时内减少酵母聚糖与巨噬细胞的结合；在较长时间的摄取后，未检测到影响。我们之前已经表明，甘露糖可能通过选择性干扰与甘露糖受体的结合来减少酵母聚糖的表面结合。在短时间暴露期间酵母聚糖与巨噬细胞结合的目前抑制作用可以完全由这种结合减少来解释。因此，巨噬细胞必须在除甘露糖受体之外的位点内化酵母聚糖。与巨噬细胞相反，小鼠巨噬细胞样细胞系P388D1缺乏甘露糖 - 糖蛋白受体。因此我们发现，酵母聚糖与P388D1的结合比与巨噬细胞的结合要轻得多，并且不受甘露糖或甘露糖 - 6 - 磷酸的影响。P388D1的自发溶酶体酶分泌也不受甘露糖的影响。关于巨噬细胞的数据证实了我们之前的建议，即干扰甘露糖受体的试剂通过直接作用于受体来抑制溶酶体酶分泌的诱导。关于P388D1细胞的数据通过排除分泌途径后期步骤的影响来支持这一断言。
