Visualization of Egypt 101 virus in the mouse's brain and in cultured human carcinoma cells by means of fluorescent antibody.

The antigens of the Egypt virus have been detected by means of the fluorescent antibody technique in the neurons of the brain and spinal cord, in both sensory and motor areas, of infected mice. The antigens have also been observed in infected human epidermoid carcinoma cells in culture. In both cases the antigens occurred in the cytoplasm of the cells exclusively. In the early stages of infection the antigen was localized about the nucleus of the human cultured cells. In some cases the staining of the antigens produced a sponge-like effect, probably because of the numerous vacuoles of lipid material. The antigens were observed in the protoplasmic connections between cells and they probably served as a main route of spread of the agent in these human cell cultures. The number of cells initially infected and showing antigen was proportional to the amount of virus added, and titration with one substrain of cells proved much more sensitive than intracerebral titration in the mouse.