IDENTIFICATION AND CHARACTERIZATION OF MATERIALS SECRETED BY CLARA CELLS

细支气管Clara细胞的功能尚不清楚， 一般认为该细胞是分泌性的。 使用模型 系统，在这个实验室开发的，我们已经确定了一个低 分子量蛋白（Mr 12，500）作为主要分泌蛋白 Clara细胞 我们还发现了 兔肺灌洗液中的蛋白质， 开发了一种简单的分离方法 抗血清 针对高度纯化的Clara细胞（纯度 大于90%）已被用于定位Clara细胞分泌 嗜锇细胞质颗粒内的CCSP蛋白（CCSP） 细支气管Clara细胞显示了 颗粒与低分子量蛋白质的分泌 应该主要通过一个受调控的途径发生。 但我们 一直无法证明调节途径，我们现在 得出结论，大多数分泌通过组成性途径发生， 包括分泌颗粒。 CCSP抗血清的应用 我们已经证明了一种免疫原性相似的 在假孕兔子宫分泌物中的蛋白质。 我们有 还从子宫分泌物中分离出子宫珠蛋白， 抗体表明CCSP和子宫珠蛋白是 免疫化学相似的蛋白质。 这些初步数据表明 细支气管Clara细胞的主要分泌蛋白， 兔可以是子宫珠蛋白。 今后的研究将力求 建立CCSP与子宫珠蛋白的关系， 这些低分子量分泌的细胞外功能 proteins.

The functions of the bronchiolar Clara cell are not known although it is generally believed that the cell is secretory. Using a model system, developed in this laboratory, we have identified a low molecular weight protein (Mr 12,500) as the major protein secreted by Clara cells. We have also identified the major secretory protein in pulmonary lavage effluents from the lungs of rabbits and developed a simple procedure for its isolation. Antiserum developed in goats against highly purified Clara cells (purity greater than 90%) has been used to localize Clara cell secretory proteins (CCSP) within the osmiophilic cytoplasmic granules of bronchiolar Clara cells indicating the storage nature of the granules and that secretion of the low molecular weight protein should occur primarily through a regulated pathway. However, we have been unable to demonstrate the regulated pathway and we now conclude that most secretion occurs via a constitutive pathway not involving the secretory granules at all. Using antiserum to CCSP we have demonstrated the presence of an immunogenically similar protein in uterine secretions from pseudopregnant rabbits. We have also isolated uteroglobin from uterine secretions, and with antibodies demonstrated that CCSP and uteroglobin are immunochemically similar proteins. These preliminary data indicate that the major secretory protein of the bronchiolar Clara cells of the rabbit may be uteroglobin. Future studies will seek to establish the relationship of CCSP to uteroglobin and focus on the extracellular function of these low molecular weight secretory proteins.