An electron microscopic study of the surface structures and hemadsorption on chick embryo cells infected with rabies...

Characteristic alterations at the surface of chick embryo cells infected with the HF-TC strain of rabies virus and the binding sites of hemadsorption were studied employing both scanning and transmission electron microscopes. The initial alteration of the cell surface structure revealed by scanning electron microscopy was an appearance of elongated and reticulated microvilli on the 2nd day after virus inoculation. On the 3rd day, numerous bullet-shaped virions could be seen budding as single, tetrapod-like structures and as radial projections both from the perikarya and microvilli. Thereafter, elongation of microvilli, formation of numerous blebs in various sizes, disappearance of filopodia, and rounding up of infected cells were observed as characteristic cytopathic effects by rabies virus infection. The attachments of goose erythrocytes to the infected cells occured in two forms. The one was adsorption of erythrocytes to the cell surface involving microvilli and filopodia in the absence of detectable virus, and the other was adsorptio n of erythrocytes to the virus particles budding from cell surface. The former could be seen from the early stage of infection through the end of observation period, while the latter was observed only on and after the 3rd day after virus inoculation. These findings were also confirmed with transmission electron microscopy.