Remold-O'Donnell E, Lewandrowski K
J Immunol. 1982 Apr;128(4):1541-4.
The correlation between activation of macrophages and increased secretion of plasminogen activator suggests that macrophages are exposed to the protease plasmin. Incubation of 125I-labeled, caseinate-elicited guinea pig peritoneal macrophages with plasmin cleaves a surface protein, gp160, characterized previously by its sensitivity to trypsin. The gp160 fragments produced by plasmin (fr85 and fr71), which remain disulfide-bonded in the membrane, comigrate with the fragments produced by trypsin, indicating close or identical cleavage sites. No other detectable 125I-labeled surface component is cleaved by plasmin. Neither gp160 nor any other detectable 125I-labeled surface component was cleaved by a series of other proteases associated with inflammation including thrombin, collagenase, pancreatic elastase, leukocyte elastase, cathepsin G, and urokinase. Analysis with the use of homogeneous plasmin from guinea pig plasma shows that concentrations as low as 50 micrograms/ml cause measurable cleavage of gp160 in 30 min.
巨噬细胞的激活与纤溶酶原激活物分泌增加之间的相关性表明，巨噬细胞暴露于蛋白酶纤溶酶中。用纤溶酶孵育125I标记的、酪蛋白引发的豚鼠腹腔巨噬细胞会切割一种表面蛋白gp160，该蛋白先前因其对胰蛋白酶敏感而被鉴定。纤溶酶产生的gp160片段（fr85和fr71）在膜中保持二硫键结合，与胰蛋白酶产生的片段迁移情况相同，表明切割位点相近或相同。纤溶酶未切割其他可检测到的125I标记表面成分。gp160和其他任何可检测到的125I标记表面成分均未被一系列与炎症相关的其他蛋白酶切割，这些蛋白酶包括凝血酶、胶原酶、胰弹性蛋白酶、白细胞弹性蛋白酶、组织蛋白酶G和尿激酶。使用来自豚鼠血浆的纯纤溶酶进行分析表明，低至50微克/毫升的浓度在30分钟内就能引起可测量的gp160切割。
