Fine structure of the alveolar macrophage of the cat and modifications of its cytoplasmic components during phagocytosis

摘要

AbstractThe alveolar macrophage of the cat shares some features with the alveolar macrophages of ordinary laboratory mammals and man, mainly a voluminous Golgi zone exhibiting evidence of secretory activity. The very numerous typical lysosomes appear to be a secretory end product. They increase in size by a fusion process. At some stage of this process dense periodic structures, crystal‐like, become visible in intermediate size lysosomes, which later form heterogeneous crystal‐like granules characteristic of the cat's alveolar macrophage.The crystal‐like granules are bounded by a unit‐membrane pattern and contain a dense periodic parallel lamellar material (crystal‐like) mixed with fluffy amorphous substance and surrounded by a clear homogeneous material. Based on its structure as observed at a high magnification, and its behavior during phagocytosis, this crystal‐like material appears to be composed of lipid.Intra‐pulmonary injection of red blood cells was carried out in order to observe the fate of the crystal‐like granules during phagocytosis as compared to that of typical lysosomes. Like typical lysosomes the crystal‐like granules become reduced in number and undergo incorporation to the phagocytic vacuoles, demonstrating their