IDENTIFICATION AND CHARACTERIZATION OF MATERIALS SECRETED BY CLARA CELLS

细支气管Clara细胞的功能尚不清楚， 对许多物种的形态学研究导致了这样的假设 细胞是分泌性的 本研究的目的是 阐明Clara细胞的分泌性质，鉴定和表征 这些分泌物并决定其细胞外功能。 使用 模型系统，在这个实验室开发，涉及分离和纯化 在Clara细胞中，我们已经鉴定了一种低分子量蛋白（12 Kd）， 这些细胞分泌的主要蛋白质。 使用抗血清制备， 我们已经证明这种低分子量蛋白质 存在于肺细胞外膜中， 10%的总蛋白由肺上皮分泌。 我们有 分离并纯化了这种低分子量蛋白质， 细胞外衬里，分析其氨基酸组成， 一般电泳性能。 这种蛋白质似乎由一种 主要和五个次要异构体。 该蛋白具有较弱的抑制活性 抗人PMN弹性蛋白酶和木瓜蛋白酶。 这些研究表明， 分子量的蛋白质作为克拉拉细胞的主要分泌产物。

The functions of the bronchiolar Clara cell are not known although numerous morphological investigations in many species have led to the hypothesis that the cell is secretory. The objectives of this research are to elucidate the secretory nature of the Clara cell, identify and characterize those secretions and determine their extracellular functions. Using a model system, developed in this laboratory, involving isolated and purified Clara cells, we have identified a low molecular weight protein (12 Kd) as the major protein secreted by those cells. Using antisera prepared against this low molecular weight protein we have demonstrated that it is also present in the pulmonary extracellular lining accounting for approximately 10% of the total proteins secreted by the pulmonary epithelium. We have isolated and purified this low molecular weight protein from the extracellular lining, analyzed it for its amino acid composition and general electrophoretic properties. The protein appears to consist of one major and five minor isoforms. The protein has weak inhibitory activity against human PMN elastase and papain. These studies identify the low molecular weight protein as a major secretory product of the Clara cell.