Neurofilaments of Kultschitsky cells in human lung.

The immunohistochemical localization of three triplet proteins of neurofilaments in normal Kultschitsky cells and tumourlets of the human lung has been studied using avidin-biotin-peroxidase complex (ABC) method. Kultschitsky cells and tumourlets have been stained with antisera against 68 K, 150 K and 200 K dalton components of the neurofilaments, respectively. Ultrastructural observations of human Kultschitsky cells have revealed the presence of bundles of intermediate filaments as well as microtubules and neurosecretory-type granules. In the tumourlets, similarly sized filaments were found, but were relatively scarce. Since intermediate filaments are thought to be specific to differentiated cells and neurofilament proteins are restricted to the neuronal tissues, we conclude that Kultschitsky cells of the lung are of neuronal nature.