In situ electron microscopical observation of cells infected with herpes simplex virus

Transport and release of herpes simplex virus (HSV) in an African green monkey kidney cell line (CV-1) was followed by electron microscopy for up to 24 h p.i. Transmission electron microscopy and scanning electron microscopy were employed. For the former approach, electron microscopical autoradiography of whole cultured cells and in situ thin section techniques were used. The following new observations were made. (1) Except in peripheral parts of the cells, where the cytoplasmic membrane could make a ruffling movement relatively freely, virus particles were found only on the dorsal surface of the cell and not on the surface facing the substratum. By observation of thin section in situ, it was confirmed that the virus particles within intracytoplasmic vacuoles were apparently released by a reverse phagocytic process from the cell surface adjacent to microvillus projections. (2) Progeny virus particles in the nucleus moved to the cell surface within 2 h after maturation.