Recognition and quantitation of herpesvirus particles in human vesicular lesions

Herpesvirus particles from crude vesicular fluid of a patient were stained with uranyl acetate and potassium phosphotungstate, and then were identified and counted by electron microscopy. Virus was seen and quantitated in all the samples taken from five vesicles. Specimens from human lesions can be prepared and examined within 3 hours, permitting rapid presumptive identification of herpesvirus.

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.

Variation of herpes simplex virus in persistently infected tissue cultures

Hinze, Harry C. (University of Wisconsin, Madison), and Duard L. Walker. Variation of herpes simplex virus in persistently infected tissue cultures. J. Bacteriol. 82:498-504. 1961.-Cultures of human conjunctiva, HeLa, and KB cells infected with herpes simplex virus (HF strain) were cultured for prolonged periods in medium containing low levels of antibody. After continuous culture of the infected cell lines for 6 months, two major changes were noted in the character of the virus present in the cultures. These changes consisted of an alteration in the type of cytopathic effect produced by the virus and marked loss of virulence for mice. Further study of the virus from the cultures revealed that it was still antigenically similar to the original strain of herpes virus. It was found that the variant produced an altered, proliferative type of cytopathic effect only in the presence of herpes antibody. The variant multiplied more slowly in human conjunctiva cells in culture than did the parent virus, and the variant had lost practically all capacity for multiplication in the brain of mice.

On the role of ribonucleic acid in animal virus synthesis. II. Studies with ribonuclease

Ribonuclease is a highly active inhibitor of vaccinia virus multiplication in vitro in the chorioallantoic membrane removed from embryonated chicken eggs. It is also a highly active inhibitor of pock formation by vaccinia and herpes simplex viruses on the chorioallantoic membrane in vivo. Marked inhibitory effects were obtained with 12.5 µg. of RNase. However, complete inhibition was not obtained with several hundred micrograms of the enzyme. RNase caused no inactivation of the infectivity of vaccinia virus particles but it had a marked inhibitory effect on multiplication of this virus when administered many hours after infection of host cells had occurred. RNase also failed to inactivate the infectivity of herpes simplex virus particles. The results obtained indicate that ribonucleic acid is necessary for the multiplication of two DNA-containing viruses; i.e., vaccinia and herpes simplex.

Observations on the fine structure of mature herpes simplex virus and on the composition of its nucleoid

The fine structure and composition of mature herpes virus have been investigated in thin sections by electron microscopy. The virus was grown in cultured HeLa cells and was collected with them. Tests for the biological activity of the infected cultures were included in the first half of the work. Preparations were fixed with both osmium and permanganate, and were embedded either in methacrylate or in aquon, a water-miscible fraction of a commercially available epoxy resin. In further experiments material fixed with permanganate was subjected to the action of specific nucleases or control medium before embedding. All the preparations showed numerous uniform particles around and between the cells and this was paralleled by considerable biological activity where tests were made on samples of the culture fluids. Mature herpes virus has been found to be round and to measure, when dehydration shrinkage is avoided, about 165 mmicro in diameter. The particle contained an eccentric round-ended rod-shaped, electron-opaque nucleoid lying in an inner zone of low density. A dense outer zone or viroplasm surrounded this, no membrane being present between the two zones. After permanganate fixation the particle was found to have an outer limiting membrane showing a triple-layered structure morphologically indistinguishable from that of the plasma membrane of the HeLa cells. The results of the digestion experiments show that herpes virus contains nucleic acid of deoxyribose type and that this is localized in the dense nucleoid. Both the findings and the methods used are discussed.

Nutritional requirements for the production of herpes simplex virus. I. Influence of glucose and glutamine of herpes simplex virus production by HeLa cells

Lewis, Vester J., Jr. (University of Oklahoma School of Medicine, Oklahoma City) and L. Vernon Scott. Nutritional requirements for the production of herpes simplex virus. I. Influence of glucose and glutamine on herpes simplex virus production by HeLa cells. J. Bacteriol. 83:475-482. 1962.-The importance of glucose and glutamine in herpes simplex virus production by HeLa cells was evaluated by variation of the composition of Eagle's basal medium. Simultaneous omission of glucose and glutamine from the serum-containing medium resulted in marked curtailment of viral synthesis. The effect was attributable neither to decreased survival time of infectious particles or of cells, nor to decreased rate of viral adsorption or penetration in the presence of the deficient medium. Therefore, the effect was probably on intracellular viral replication.When the requirements for glucose and glutamine were determined separately, it was found that viral production was reduced in glucose-deficient medium. In contrast, a medium which was complete except for restriction of the glutamine content to that occurring naturally in the serum component supported significantly greater viral multiplication than did the complete medium. Limited viral replication occurred with medium which lacked both glutamine and serum. Viral multiplication in the presence of serum-free medium was stimulated by the addition of glutamine.

Observations on the mode of release of herpes virus from infected HeLa cells

The development of a well adapted strain of herpes virus has been studied in HeLa cells using thin sectioning techniques for electron microscopy. Particular attention was directed to events in the cytoplasm and certain new features were observed. Profuse immature particles with a nucleoid and single limiting membrane were present in the nuclei of infected cells, often in crystalline array; morphologically indistinguishable immature particles were also found very frequently in the cytoplasm. Cells with such particles were intact and well preserved, and contained smooth vacuoles apparently derived from the Golgi component of the endoplasmic reticulum. The cytoplasmic particles escaped from the cells by bulging out as buds through the cell membrane or through that of the cytoplasmic vacuoles until they were attached only by a pedicle and then became free. During this process the particles were gradually enclosed by the membrane through which they passed and carried a coat of it with them as they matured. After permanganate fixation the triple-layered structure of the cell membrane and vacuolar membranes was evident and was identical with that of the outer coat of the mature virus. These findings are discussed both in relation to different types of virus structure and to function in the endoplasmic reticulum and cell membrane.