Electron microscopic observations on the development of herpes simplex virus.

Study of the J.M. strain of herpes simplex virus in human amnionic and HeLa cell tissue cultures revealed the presence of intranuclear crystals composed of viral particles with a single membrane enclosing a central body. Randomly dispersed virus with double coats was seen in the nuclear matrix and between multiple membranes at the nuclear periphery. The majority of intracytoplasmic viral particles were within walled vacuoles. It is suggested that this strain of virus differentiates and frequently crystallizes at template sites which are characterized by aggregates of granules near the nuclear margin; that particles, either singly or occasionally in small groups, become enclosed by a second peripheral membrane while still within the nucleus; that the virus can pass into the cytoplasm through reduplications of the nuclear membrane which are deposited behind the virus in such a manner as to prevent rupture of the nucleus; that most of the intracytoplasmic virus is contained within sacks formed by nuclear membranes; and that rupture of these sacks at the cell surface results in extrusion of virus without disruption of the cell. No evidence was obtained to support the hypothesis that virus develops in the cytoplasm. Examination of the H.R. and C.G. strains of herpes simplex virus in identical cell lines grown under similar conditions failed to show viral crystals, but reduplication of the nuclear membranes was evident. Study of the J.M. strain in cells of chicken embryo chorioallantoic membranes indicated that the basic mechanisms of viral development and release did not differ from those operating in HeLa and human amnionic cells.