Measles virus: study of induced transfer of biological properties. II. Fluorescence studies on rescue of neurotropic strain in cell culture.

HeLa cells are non-permissive for the neurotropic suckling mouse strain of measles virus (MMV), but are permissive for cell-adapted Edmonston strain of measles virus (EDm). Fluorescence and electron microscopy demonstrated no membrane fluorescence and no membrane associated viral components, as well as characteristic lack of nuclear antigen after MMV infection of HeLa cells. This appearance differs markedly from the membrane, cytoplasmic and nuclear fluorescence after Edm infection of HeLa cells. Fluorescence microscopy demonstrates fusion of the two dissimilar syncytia after mixed infection. This suggests Edm envelopment of MMV nucleocapsids may be the means of MMV rescue in this system.