Nadziejko C, Finkelstein I, Balmes J R
Institute of Environmental Medicine, New York University Medical Center, Tuxedo 10987, USA.
Am J Respir Crit Care Med. 1995 Nov;152(5 Pt 1):1592-8. doi: 10.1164/ajrccm.152.5.7582300.
Secretory leukocyte protease inhibitor (SLPI) and elafin are structurally similar, low-molecular-weight antiproteases produced in the lung. We have developed a simple method for distinguishing the antiprotease activities of SLPI and elafin in lung lavage fluid from those of alpha 1-antitrypsin (alpha 1-AT) that is based on the resistance of the low-molecular-weight antiproteases to inactivation by cetyltrimethylammonium bromide. In a study of 23 healthy, nonsmoking volunteers, we found that the low-molecular-weight antiproteases accounted for 22 +/- 2% (mean +/- SEM, n = 23) of the total neutrophil elastase-inhibitory capacity of human bronchoalveolar lavage fluid (BALF). Elafin activity was below the limit of detection. SLPI activity (as measured by inhibition of alpha-chymotrypsin) accounted for 72 +/- 4% (mean +/- SEM, n = 23) of the low-molecular-weight antiprotease activity in BALF. Measurements of SLPI in the lavage fluid samples by enzyme-linked immunosorbent assay (ELISA) agreed closely with values obtained by measuring the activity of this inhibitor. The activity of the low-molecular-weight antiproteases decreased significantly (p < 0.05), from 9.0 +/- 0.8 to 7.0 +/- 0.6 pmol of neutrophil elastase inhibited per mL (mean +/- SEM, n = 23), following acute ozone exposure.
分泌型白细胞蛋白酶抑制剂（SLPI）和弹性蛋白酶抑制因子在结构上相似，是在肺中产生的低分子量抗蛋白酶。我们开发了一种简单的方法，基于低分子量抗蛋白酶对十六烷基三甲基溴化铵失活的抗性，来区分肺灌洗液中SLPI和弹性蛋白酶抑制因子的抗蛋白酶活性与α1-抗胰蛋白酶（α1-AT）的抗蛋白酶活性。在一项对23名健康非吸烟志愿者的研究中，我们发现低分子量抗蛋白酶占人支气管肺泡灌洗液（BALF）总中性粒细胞弹性蛋白酶抑制能力的22±2%（平均值±标准误，n = 23）。弹性蛋白酶抑制因子的活性低于检测限。SLPI活性（通过抑制α-糜蛋白酶来测量）占BALF中低分子量抗蛋白酶活性的72±4%（平均值±标准误，n = 23）。通过酶联免疫吸附测定（ELISA）对灌洗液样本中的SLPI进行测量，其结果与通过测量该抑制剂活性获得的值密切相符。急性臭氧暴露后，低分子量抗蛋白酶的活性显著降低（p < 0.05），从每毫升抑制9.0±0.8皮摩尔中性粒细胞弹性蛋白酶降至7.0±0.6皮摩尔（平均值±标准误，n = 23）。
