Electron Microscopy of Hela Cells Infected With Adenoviruses

Abstract

HeLa cells were infected with adenoviruses (types 1–4) and sectioned for electron microscopy after intervals of 20 to 48 hours. Clusters of virus-like particles were found within the nuclei of infected cultures but not in those of uninfected controls. The particles were often arranged in rows as if in crystalline formation. Maximal diameter of particles was approximately 65 mµ, and internal bodies were demonstrated. Lesions of infected cells included target-like structures of the nuclear membrane, large nuclear vacuoles (type 2), and increased numbers of large irregular electron-dense granules in the cytoplasm 48 hours after infection. Examination of infected cultures by light microscopy, using the Feulgen reaction, showed intranuclear inclusion bodies and a cytopathogenic effect consisting of clumping of cells without pyknosis of nuclei. A lipide stain showed numerous cytoplasmic granules that were not identical with the large, irregular, electron-dense granules of the cytoplasm. Practically all the cells showed the viral cytopathogenic effect, but only a minority of cells were found to contain virus-like particles or intranuclear inclusion bodies.

Observations on the Fine Structure of Type 5 Adenovirus

“…The size of the virus particle reported here agrees well with all previous findings (1)(2)(3)(4)(5) in which material has been examined without air drying and possible accompanying distortion, and the diameter of the inner body or nucleoid also shows good agreement. The apparent structural differentiation observed here in the nucleoid has not previously been described; although so far no information is available concerning the significance of this finding, it is tempting to regard it as a reflection of the presence of more than one component within this region of the viru~ FIc.…”

“…Since the first observation with the electron microscope of intranuclear virus-like particles in sections of tissue culture cells infected with adenovirus (1), numerous later studies of similar material have established certain morphological features of this agent (2)(3)(4)(5). The particles have been reported to be round or ellipsoid and an inner body and outer limiting membrane have been described (3)(4)(5).…”

“…The particles have been reported to be round or ellipsoid and an inner body and outer limiting membrane have been described (3)(4)(5). On the other hand particles dried from suspension and examined as whole mounts appeared polyhedral in shape (6,7), but some workers consider that this may merely represent an artefact caused by the drying (5).…”

The Occurrence of Intranuclear Crystals in Living HeLa Cells Infected with Adenoviruses

“…These findings confirm observations reported by other investigators (2)(3)(4)(5). In order to exclude the possibility that the crystals might have resulted from fixation or other processes involved in preparing the material for light and electron microscope studies, living cultures were examined under the phase and interference microscopes.…”

Newly Recognized Respiratory Tract Viruses

“…Increase in titer of extracellular virus occurs significantly later, and throughout the course of infection the titer of virus in the cells is higher than that in the culture medium (82). In contrast to morphologic evidence of viral replication in the nucleus (46,47,48), differ ential centrifugation studies indicate that the majority of infectious virus is in the cytoplasm [Denny, Boyer & Ginsberg (84)]. …”