Abstract
Successive cellular changes leading to damage induced in human epithelial FL-line cells by poliovirus infection were followed by means of phase cinematography and described on the basis of tine records of living cells and fixed-stained specimens. The first visible change appeared as acidophilic inclusions in nuclei of stained specimens as early as 5 hours after infection. Following distortion of the nucleus, a marked increase in basophilia and the appearance of α paranuclear mass were noted in the cytoplasm. With the development of this mass, the nucleus located in the peripheral area of the cell became intensively wrinkled and distorted. Then several vacuoles appeared in the cytoplasm, and a marked blebbing of the cell surface followed, resulting in shrinkage of the cell. The cell damage was characterized morphologically 20 to 24 hours after infection by an eosinophilic cytoplasmic mass, severe distortion of the nucleus and fragmentation of nuclear material leading to pycnotic degeneration of nuclei. The nucleoli and acidophilic intranuclear inclusions remained unchanged during the course of pycnotic degeneration of cells. Degenerative changes leading to cell damage proceeded rather slowly in infected cells.
