Filamentous structures of type 2 Herpesvirus hominis infection of the chorioallantoic membrane

Similarities and Differences in the Development of Laboratory Strains and Freshly Isolated Strains of Herpes Simplex Virus in HEp-2 Cells: Electron Microscopy

HEp-2 cells infected with two laboratory strains (mP and MP) and two freshly isolated strains (F and G) of herpes simplex virus were fixed at intervals between 4 and 50 hr postinfection and sectioned, and were then examined with the electron microscope. These studies revealed the following. (i) All four strains caused identical segregation of nucleoli and aggregation of host chromosomes at the nuclear membrane. (ii) The development of MP virus could not be differentiated from that of its parent mP strain. (iii) There were quantitative differences between laboratory (mP) and freshly isolated (F) type 1 strains. Thus, cells infected with F contained numerous nuclear crystals of nucleocapsids and relatively few cytoplasmic structures containing enveloped nucleocapsids. Conversely, cells infected with mP or with MP virus contained numerous cytoplasmic structures with enveloped nucleocapsids and relatively few nuclear crystals of nucleocapsids. (iv) There were qualitative differences between type 2 strain (G) isolated from genital lesions and type 1 strains. Thus, cells infected with the G strain contain numerous filaments in nuclei and unenveloped and partially enveloped nucleocapsids in the cytoplasm. Of particular interest is the finding that cytoplasmic membranes in apposition to nucleocapsids were thickened and bent as if they were enveloping the particle. The significance of the qualitative differences in the development of the four strains is discussed.

Electron microscopy for the rapid detection and identification of viruses from clinical specimens

The advantages of using electron microscopy for rapid diagnosis of virus infection from clinical specimens, for identification of virus isolates with unusual properties, and for monitoring endogenous agents in cell cultures are illustrated by several actual cases that have occurred over the years. The importance of using morphological characteristics of viruses for initial identification is emphasized.

Characterization of the restricted component of Epstein-Barr virus early antigens as a cytoplasmic filamentous protein

Four monoclonal antibodies produced against the restricted component of the Epstein-Barr virus (EBV) early antigen (EA-R) precipitated a polypeptide with an approximate molecular weight of 85,000. Three of these antibodies prepared against the native 85,000-molecular-weight protein (85K protein) reacted by immunofluorescence with acetone-fixed smears but not methanol-fixed smears of EBV-producing cells activated with tumor-promoting agent and sodium butyrate. The fourth monoclonal antibody which was produced against the denatured 85K protein reacted with both acetone-fixed cells and methanol-fixed cells. Blocking of direct immunofluorescence by the different monoclonal antibodies established that these monoclonal antibodies were directed against three different epitopes expressed on the 85K protein. The cytoplasmic staining pattern produced by each antibody was granular during the first 24 to 28 h after induction, developed into filamentous structures about 36 h after induction, and then began to aggregate after 48 h. Similar structures were observed in human placental cells transfected by EBV DNA and stained with three of the monoclonal antibodies. These results suggest that the EA-R polypeptide is assembled into filaments during the EBV lytic cycle. The significance of this in regards to replication has yet to be determined. Biochemical characterization of this major EA-R component did not reveal any major differences in this protein isolated from different cell lines.

Ultrastructural studies on human lymphoblastoid cells treated with n-butyrate and 12-O-tetradecanoylphorbol-13-acetate

The effects of n-butyrate and/or 12-O-tetradecanoylphorbol-13-acetate (TPA) on Raji and P3HR-1 cells were examined using electron microscopy. n-Butyrate treatment caused a decrease in the number and elongation of surface microvilli. In addition, well-developed rough endoplasmic reticulum and a marked decrease in condensed chromatin clumps were observed in the nucleus. The filamentous structures and nuclear membrane-like structures, which were not reported previously, appeared occasionally in the nucleus. On the other hand, in the cells treated with TPA no marked morphological changes were observed except the higher cytoplasmic:nuclear ratio. n-Butyrate-induced morphological changes were not inhibited when combined with TPA or retinoic acid. Electron microscopic studies showed remarkable differences in morphological change in these cells treated with n-butyrate and/or TPA.

Filamentous structures associated with Epstein-Barr virus-infected cells

After the onset of Epstein-Barr virus DNA and protein synthesis 10 h after superinfection of Raji cells (a cell line containing Epstein-Barr virus DNA but not producing virus), filamentous structures 25 nm in diameter and 0.2 to 1.4 micrometers in length could be detected in the cell cytoplasm by electron microscopy. These structures banded in metrizamide gradients with viral DNA and proteins, but at a density different from that of virions or nucleocapsids. These filaments, enriched in a 155,000-dalton protein similar in size to a major nucleocapsid protein of Epstein-Barr virus, may represent intermediates in viral nucleocapsid assembly.

Non-inflammatory herpes simplex hepatitis in an adult with chronic neutropenia

We report the case of a young woman with chronic neutropenia, in whom hepatitis, extensive herpetic eruption and herpes simplex viremia developed after genital herpetic ulceration. Although severe liver necrosis was present, the patient's death did not result from hepatic failure. No inflammatory cell infiltration was found circumscribing the multiple necrotic foci in the liver. This absence of inflammatory cell infiltration reflects the host's inability to normally restrain herpes simplex virus dissemination and, in this patient, might be the consequence of chronic neutropenia.

Structure of pocks on the chorioallantoic membrane of fertile hens' eggs induced by herpes simplex virus types 1 and 2

The fine structure of the chorioallantoic membrane of the fertile hen's egg infected with herpes simplex virus Types 1 and 2 was examined. Lesions induced by Type 1 virus were small, confined to the chorionic layer of the membrane and proliferative in nature with slight cellular infiltration into the mesoderm after incubation up to 7 days. With the Type 2 virus-induced pocks, reaction occurred throughout the thickness of the chorioallantoic membrane, and haemorrhages, necroses, ulceration and cellular infiltration of the mesoderm were prominent features. Inoculation of the membranes with Type 2 virus resulted in a large number of infected chorion cells compared with Type 1, whilst the cells of the mesoderm and blood vessels became infected with Type 2 virus but not Type 1. Two types of intranuclear granules, lattice structures in both nuclei and cytoplasm and virus particles with variously structured cores were found specifically in Type 2 infected cells.

Morphological observations of the replication of herpesvirus tamarinus in RL-33 cells

The replication in RL-33 cells (rabbit lung cell line) of herpesvirus tamarinus isolated from cotton-topped marmosets (Saguinus oedipus) was investigated by electron microscopy. In the early stages of infection, ring-shaped and granular structures, and fibrillar materials were recognized in the nucleus. Immature particles were often found in such nuclei. The envelope of the virus was formed by budding through intracytoplasmic membranes, the inner nuclear membrane or the membrane of intracytoplasmic vacuoles. Virus particles which appeared to be budding through the plasma membrane were also observed. Aberrant viral forms were produced by independent budding of both the inner and outer nuclear membranes. The mature particles once enveloped acquired a second envelope by budding through intracytoplasmic double membranes or the outer nuclear membrane. Unusual virus-associated structures were observed in the cytoplasm and nucleus. Virus particles appeared to be released by the process of reverse phagocytosis.

Tubular structures in the cervix of mice experimentally infected with herpes simplex virus type 2

Experimental infection of the C3H/N mouse genital tract was demonstrated after intravaginal inoculation with herpes simplex virus type 2 (HSV-2). About 75% of the infected animals died by Day 7, and 75% of the surviving animals had severe vaginitis or neurological signs on Day 7. Titers of the virus recovered from vaginal secretions of infected animals reached a maximum on Day 2 and gradually decreased until Day 7. On the other hand, under the electron microscope, virus particles and tubular structures could be found in the nuclei of infected cells of the cervix in the 1st, 2nd and 4th days after infection. All cases in which virus particles could be found in the nuclei of infected cells were also positive for tubular structures and vice versa. These observations indicate that in situ diagnosis of HSV-2 infection can be made in the mouse model. The same method would be applicable for the diagnosis of human HSV-2 infection.

Herpes simplex virus (HSV) infection of organotypic nerve cell cultures. Tubule-like structures in the nuclei of cells infected with type 2 but not with type 1 virus

In HSV-2 infected cultures, intranuclear tubule-like structures were found more commonly in fibroblasts and central nervous system (CNS) neurons than in oligodendrocytes, astrocytes, satellite and Schwann cells, but were found least often in peripheral neurons.

Effects of antimetabolites on the production of tubular structures in Vero cells infected with herpes simplex virus type 2

Treatment of Vero cells infected with herpes simplex virus type 2 with the proper concentrations of hydroxyurea (HU) reduced the production of infectious virus and markedly increased the accumulation of tubular structures in the nuclei when the drug was added within 6 hours after infection. Similar accumulation of tubular structures in the infected nuclei was also observed when infected cells were treated with phosphonoacetic acid at proper concentrations. The release of HU-treated, herpes simplex virus type 2-infected cells from the drug-induced blocking of synthesis of infectious virus resulted in the marked decrease of tubular structures coincidentally with the beginning of production of infectious virus. The data suggest the possibility that the disappearance of tubular structures may be related to the active production of infectious virus.

Necrotising balanitis due to a generalised primary infection with herpes simplex virus type 2

Virological studies have proved herpes simplex virus type 2 to be the cause of the severe primary infection in a 37-year-old man with necrotising balanitis. Symptoms of urethritis preceded the appearance of a severe local lesion; dissemination of infection occurred and lesions developed on the skin of the scalp, neck, trunk, buttocks, arms, legs, and feet. No evidence of involvement of the central nervous system was found, and the penile and skin lesions improved rapidly after the application of 5% idoxuridine in dimethylsulphoxide. Recurrences occurred at various skin sites at six to seven months after the primary infection.

Electron microscope observations on tubular structures in cells infected with herpes simplex virus type 2

The fine structure of filamentous structures and lattice-like structures found in herpes simplex virus type 2-infected cells was studied. By specimen tilting experiments, it was demonstrated that the lattice-like structures were the cross-sectional views of the tubular structures and the filamentous structures were the longitudinal sections. The observation in negatively stained preparations of isolated tubular structures revealed that the structure was constructed by regular array of ring shaped elements. A hypothetical model is presented for tubular structures constructed on the basis of the present findings. The tubular structures appeared as early as 6 hours after infection and reached a maximum at 12 hours.

Identification of strains of herpes simplex virus by comparison of the density of their DNA using the preparative ultracentrifuge

The buoyant densities of the DNA of herpes simplex virus type 1, type 2 and Pseudorabies virus, as determined in the analytical ultracentrifuge, are 1.725, 1.727 and 1.731 correlating with G+C contents of 67, 69 and 73 per cent respectively. The density differences for the DNA's of type 1 and type 2 herpes simplex viruses have been confirmed in experiments with isotopically labelled DNA from four type 1 and six type 2 strains by preparative CsCl gradient ultracentrifugation. The DNA of all the type 2 strains was denser than that of any of the type 1 strains examined. Despite these differences in DNA base composition of type 1 and type 2 strains, nearest neighbour analysis of their DNA's disclosed no obvious differences in doublet pattern or general design.

Characterization of genital strains of Herpesvirus hominis

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Unusual intranuclear tubular structures associated with the maturation of Herpesvirus saimiri in monkey kidney cell cultures

Unusual intranuclear tubules have been observed in cultures of both African green monkey and owl monkey kidney cells infected with Herpesvirus saimiri; the material was studied in thin sections with the electron microscope. The tubules were seen in about 10% of virus-containing cells at the stage when the virus matured by budding at the nuclear membrane, measured 160-180 nm in diameter and up to 3.6 μm in length, were bounded by an outer "membrane" and contained beneath this an electron dense repeating structure arranged either as a coil or a series of evenly spaced rings. The morphology and significance of the tubules are discussed.

Classification of Mouse Thymic Virus as a Herpesvirus

Classical herpesvirus particles were observed by thin-section electron microscopy in thymus tissues from mice inoculated with mouse thymic virus. Intranuclear particles measured approximately 100 nm in diameter, and cytoplasmic and extracellular particles measured 135 nm in diameter. The morphology of mouse thymic virus particles together with its properties of heat and ether lability suggest that thymic virus should be classified as a member of the herpesvirus group.

Herpesvirus type 2 isolated from cervical tumor cells grown in tissue culture

A herpesvirus has been isolated from spontaneously degenerating cultures of cervical tumor cells grown in vitro. The virus was identified as a type 2 herpesvirus on the basis of biologic properties, including plaque morphology and microtubule formation in infected HEp-2 cells, and of immunologic specificity as determined by neutralization. Herpesvirus antigens and virus particles were not seen in duplicate cultures of viable cervical tumor cells.

Channel catfish virus: a new herpesvirus of ictalurid fish

Channel catfish virus was studied in ictalurid fish cell culture, the only system of fish, amphibian, avian, and mammalian cells found to be susceptible. Channel catfish virus infection resulted in intranuclear inclusions and extensive syncytium formation. Replication occurred from 10 to 33 C, but not higher. Best growth was from 25 to 33 C, and the amount of virus released nearly equalled the amount which remained cell-associated. The virus was labile to lipid solvents, and indirect determinations with labeled precursors and a metabolic inhibitor showed evidence of deoxyribonucleic acid. Electron microscopy showed progeny virus, about 100 nm in diameter, in various stages of development in cell nuclei by 4 hr. Present also were nuclear masses of exceptionally electron-dense lamellar material, with a unit dimension of 10 to 15 nm. Virus was enveloped at the nuclear membrane and in cytoplasmic vacuoles, resulting in virions having a diameter of 175 to 200 nm. Negative staining demonstrated icosehedral symmetry and 162 capsomeres. Our data indicate that channel catfish virus is a herpesvirus.

Biological characteristics of cloned populations of herpes simplex virus types 1 and 2

By using cloned types 1 and 2 herpes simplex virus, obtained by selecting large and small plaques produced by material from human lesions, studies were performed to compare properties between preparations of each type. Regarding the rate of inactivation by ultraviolet light, no differences were found between the two antigenic types and none between the preparations obtained from either type. In contrast, type 1 preparations were found to be more readily inactivated at 45 C than type 2. Plaque size of cloned preparations changed by passage in cell culture. A broader range of plaque sizes was obtained, and average plaque size was larger. After 20 passages, preparations obtained from different types gave rise to one of three kinds of cytopathic effect. The cytopathic effect produced by type 1 preparations remained as before 20 passages and consisted of round cells in a compact central mass. For type 2, two kinds of cytopathic effect were seen in cloned preparations. This consisted of aggregates of round cells (seen in preparations before 20 passages) or of large, loose aggregates of round cells of various sizes. Results from neutralization studies using virus before and after 20 passages in cell culture versus antisera prepared against live or ultraviolet-inactivated virus showed no differences between cloned preparations obtained from a given type.

Morphological changes in productive and abortive infection by feline herpesvirus

Feline herpesvirus produces characteristic morphological alterations in feline kidney cells. Nucleocapsid particles are formed in infected nuclei and are enveloped as they pass through the modified inner nuclear membrane. Aggregates of dense granular material and filamentous structures also regularly appear in infected nuclei. Infection of human embryonic lung cells by feline herpesvirus results in the appearance of intranuclear inclusion bodies, aggregates of dense granular material, and bundles of parallel filaments but no nucleocapsid particles.