Sequence of Morphological Changes in Epithelial Cell Cultures Infected With Poliovirus

Abstract

The cytopathic changes induced by poliovirus in cell cultures, first described by Robbins, Enders, and Weller (1), have since been observed by many workers. The description of the morphological changes however, has been limited to the late stages in the swollen and rounded cells, when the changes were so pronounced that they could be detected in the unstained preparations. In a preliminary investigation, it was noted that virus production occurred several hours before the cytopathic effect could be detected in living cultures. The possibility was then considered that a finer cytological study might show changes in the early stages of the cycle of virus multiplication in cultured cells. The present paper reports such a study, in which the sequence of intracellular changes occurring in monolayer cultures of monkey kidney cells after infection with poliovirus, has been related to the growth cycle of the virus. As the experiments were designed to determine the temporal relationship existing between the morphological changes in the infected cells and the appearance of newly formed virus within the cells and in the culture fluid, two conditions had to be fulfilled. Firstly, the cells in the culture should be infected within a brief period; ideally, simultaneous infection of all cells should occur. Secondly, a large proportion of the available cells should be infected with the original inoculum, to insure that the changes observed were actually induced by the seed virus. Materials and MethodsSince the synthesis of poliovirus in monkey kidney cells in tissue culture is rapid (complete within 8 hours), a variable lag in the response of the cells, due to a delay in virus adsorption or other factors, could result in a wide variation in the morphological character° istics of the ceils at a given time.

GROWTH CHARACTERISTICS OF POLIOVIRUS IN HELA CELLS: NUCLEIC ACID METABOLISM

“…It will be noted that at the 7th hour, when 90 per cent of the total viral yield had been formed, only 1 per cent of the new virus was in the extra-cellular state. These data dearly indicate an intracellular phase in the development of poliovirus as has been reported by other investigators (13,14). Mature virus appears in the cytoplasm after the synthesis of RNA has begun.…”

A Phase Cinematography Study on Morphological Changes of FL‐Line Cells Following the Infection of Poliovirus

“…The vacuoles lay in a hyaline area in the vicinity of the nucleus, but migrated later, with intensive blebbing, toward the peripheral area of the cytoplasm. Lwoff et al [5] and Reissig et al [9] suggested that vacuolization and blebbing or bubbling play an important role in the possible mechanism of virus release by still living cells.…”

Vesicular Exocytosis of Foot-and-Mouth Disease Virus from Mammary Gland Secretory Epithelium of Infected Cows

“…The release of virus particles, free or present in membrane-limited vesicles, from viable cells in cell culture systems has been reported by a number of authors (Reissig et al, 1956;Melendez, 1959;Khera & Dhillon, 1962;Dunnebacke et al, 1969;Yilma et al, 1978 and co-workers (1978) proposed that the release of FMD virus from BK cell culture monolayers in 'cytoplasmic blebs' may be a general release mechanism for the picornavirus group. However, in the present study, FMD virus was observed not only in apparently normal bovine mammary gland cells in vivo, but also in intimate association with secretory cell release mechanisms for casein and lipid.…”