Electron Microscopic Studies of Rubella Virus

SUMMARY Electron microscopy of BHK-21 and BS-C-1 cells infected with rubella virus revealed spherical particles measuring 50 to 85 nm. in diameter and some elongated forms, predominantly in the budding stage, up to 240 nm. in length. The sequential steps in the development of the virion, beginning with the initial budding stage to the completion of the mature form, were studied. In addition, ferritin-labelled rubella antibodies were used to tag virus particles in various stages of maturation. Surface membranes of infected cells which had undergone antigenic changes without morphological alteration were also tagged; presumably such areas are the sites of haemadsorption of pigeon red blood cells to a seemingly normal-appearing cell membrane. Haemadsorption with and without virus particles functioning as bridges between cells is illustrated.