Alterations in Glycosphingolipid Patterns in a Line of African Green Monkey Kidney Cells Infected with Herpesvirus

The major glycosphingolipids (GSLs) of a line of African green monkey kidney cells (BGM) were characterized as glucosylceramide, lactosylceramide, galactosyl-galactosyl-glucosylceramide, and N-acetylgalactosaminyl-galactosyl-galactosyl-glucosylceramide. Neutral GSLs accounted for approximately 80% of the total GSLs isolated. The predominant gangliosides were N-acetylneuraminyl-galactosyl-glucosylceramide, N-acetylgalactosaminyl-N-acetylneuraminyl-galactosyl- glucosylceramide, and galactosyl-N-acetylgalactosaminyl-N-acetylneuraminyl -galactosyl-glucosylceramide. The incorporation of labeled galactose into GSLs was compared in mock-infected and herpes simplex virus type 1-infected BGM cells. Herpes simplex virus type 1 infection resulted in a three- to four-fold increase in galactose incorporation into glucosylceramide and a decrease in galactose incorporation into galactosyl-galactosyl-glucosylceramide and N-acetyl-galactosaminyl-galactosyl-galactosyl-glucosylceramide. The virus-induced alteration in the GSL labeling pattern occurred early in infection, before the release of infectious virus, and was not prevented by the presence of cytosine arabinoside. Treatment of uninfected BGM cells with cycloheximide resulted in alterations in the GSL pattern which were similar to those observed in herpes simplex virus type 1-infected cells. These observations suggest that an early virus function such as inhibition of host cell protein synthesis is responsible for the observed alterations of GSL metabolism. Experiments with a syncytium-producing strain of herpes simplex virus type 1, herpes simplex virus type 2, and pseudorabies virus indicated that other herpes viruses altered GSL metabolism in a manner similar to herpes simplex virus type 1.     

Partial purification and characterization of the ribonucleotide reductase induced by herpes simplex virus infection of mammalian cells.

In this report we confirm and further characterize the induction of a novel ribonucleotide reductase after herpes simplex virus infection of mammalian cells. Induction of the enzyme was observed at a multiplicity of infection of 1 PFU/cell or greater and was found to be maximal (three- to sixfold the activity in mock-infected controls at 6 to 8 h postinfection at a multiplicity of infection of 10 PFU/cell. Partial purification and subsequent characterization of the reductase activity from infected cells demonstrated the existence of two enzymes which could be separated by precipitation with ammonium sulfate. One of the activities precipitated at between 35 and 55% salt saturation, as did the enzyme from control cells, whereas the novel activity precipitated at 0 to 35% saturation. This latter enzyme was similar to the herpes simplex virus-induced reductase described by others in its lack of requirement for Mg2 and its resistance to inhibition by dTTP and dATP; in addition, we found that it was inhibited by ATP, whereas the enzyme from control cells displayed an absolute requirement for the nucleotide. Both enzymes were equally inhibited by pyridoxal phosphate and showed similar cold and heat stability. The enzyme induced by herpes simplex virus infection, however, was much more labile than the control enzyme upon purification.     

Use of Disposable Micro Tissue Culture Plates for Antiviral and Interferon Induction Studies

A reproducible test system requiring small amounts of test compound was developed for evaluating antiviral and interferon-inducing activity. In the antiviral experiments, KB cells were grown in disposable polystyrene microplates covered with a standard domestic plastic wrap. Viruses used in the system were types 1 and 2 herpes simplex virus, vaccinia virus, type 3 adenovirus, myxoma virus, pseudorabies virus, type 3 parainfluenza virus, types 1A and 13 rhinovirus, vesicular stomatitis virus, coxsackievirus B, and type 2 poliovirus. Inhibition of viral cytopathogenic effect was the primary criterion of evaluation of antiviral activity. Reduction in cell and supernatant fluid virus titers was used as a secondary means of evaluation. The microplate system was adaptable for determining prophylactic, therapeutic, and inactivating effects against viruses. Mouse L-929 cells were used for the interferon induction studies, with vesicular stomatitis virus utilized as the indicator of interferon activity. Known active compounds evaluated in this microplate system had activity similar to that seen in macro in vitro systems.     

Ribonucleotide Reductase Activity of Synchronized KB Cells Infected with Herpes Simplex Virus

The replication of herpes simplex virus (HSV) is unimpeded in KB cells which have been blocked in their capacity to synthesize deoxyribonucleic acid (DNA) by high levels of thymidine (TdR). Studies showed that the presence of excess TdR did not prevent host or viral DNA replication in HSV-infected cells. In fact, more cellular DNA was synthesized in infected TdR-blocked cells than in uninfected TdR-blocked cells. This implies that the event which relieved the TdR block was not specific for viral DNA synthesis but allowed some cellular DNA synthesis to occur. These results suggested that HSV has a means to insure a pool of deoxycytidylate derivatives for DNA replication in the presence of excess TdR. We postulated that a viral-induced ribonucleotide reductase was present in the cell after infection which was not inhibited by thymidine triphosphate (TTP). Accordingly, comparable studies of the ribonucleotide reductase found in infected and uninfected KB cells were made. We established conditions that would permit the study of viral-induced enzymes in logarithmically growing KB cells. A twofold stimulation in reductase activity was observed by 3 hr after HSV-infection. Reductase activity in extracts taken from infected cells was less sensitive to inhibition by exogenous (TTP) than the enzyme activity present in uninfected cells. In fact, the enzyme extracted from infected cells functioned at 60% capacity even in the presence of 2 mm TTP. These results support the idea that a viral-induced ribonucleotide reductase is present after HSV infection of KB cells and that this enzyme is relatively insensitive to inhibition by exogenous TTP.     

Change of enzyme activities during the early stage of influenza virus infection

Intracellular activities of various hydrolytic enzymes were investigated in monkey kidney cells infected with the $\text{A}\text{NWS}$ strain of influenza virus. At the early stage of infection, there was a significant decrease in the activity of β-D-galactosidase, α-D-mannosidase, $\text{N}$-acetyl-β-D-glucosaminidase, acid and alkaline phosphatase. The decrease was roughly proportional to the multiplicity of infection, and restored at 2 hr after the infection. Corresponding to this intracellular decrease, there was an increase in the activities of these enzyme outside the cells. The results suggested that these hydrolytic enzymes would be released from the cell membrane or the lysosomes near the membrane in the process of adsorption and penetration of the virus particles.     

Virus-specific Ribonucleic Acid Synthesis in KB Cells Infected with Herpes Simplex Virus

The production of virus-specific ribonucleic acid (RNA) was investigated in KB cells infected with herpes simplex virus. A fraction of RNA annealable to virus deoxyribonucleic acid (DNA) was found in these cells as early as 3 hr after virus inoculation. Production of this species of RNA increased up to 6 or 7 hr after infection, at which time elaboration of virus messenger RNA (mRNA) declined. At 24 hr after infection, the rate of incorporation of uridine into this RNA was approximately one-half of the rate present at 6 hr after inoculation. Nucleotide analysis of the RNA annealable to virus DNA was compatible with that expected for virus mRNA. Centrifugation showed considerable spread in the size of the virus-induced nucleic acid, the bulk of this RNA sedimenting between 12 and 32S. Incorporation of uridine into cell mRNA, ribosomal precursor RNA, and soluble RNA was suppressed rapidly after infection. As is the case with most other cytocidal viruses investigated to date, virus-induced suppression of cell RNA synthesis appears to be a primary mechanism of cell injury.     

Induction of deoxypyrimidine kinase activity in human embryonic lung cells infected with varicella-zoster virus.

Deoxypyrimidine kinase (deoxythymidine [TdR] kinase and deoxycytidine kinase) activity was induced in human embryonic lung cells after infection with varicella-zoster virus (VZ virus). Increased enzyme activity was also produced by using cell-associated virus as inoculum instead of cell-free virus. Anti-VZ virus serum inhibited both the appearance of cytopathic effect and the induction of enzyme activity. The induced TdR kinase activity was more thermostable than that induced by herpes simplex virus type 1. Also, the TdR kinase activity of VZ virus-infected cells was inhibited by dTTP less than in mock-infected cells and more than in herpes simplex virus type 1-infected cells.     

Interleukin-12 exhibits potent antiviral activity in experimental herpesvirus infections.

The prophylactic and therapeutic efficacy of interleukin-12 was studied by using murine models of herpes simplex virus infection. Prophylactic administration consisted of two intraperitoneal doses of interleukin-12 given 48 and 24 h prior to infection. Therapeutic intraperitoneal administration of interleukin-12 commenced 6 h after the mice were infected with herpes simplex virus and was continued daily for a total of 5 days. Interleukin-12 therapy improved the survival rates of mice with systemic herpes simplex virus infection compared with those of placebo-treated infected mice. Subcutaneous administration of interleukin-12 also improved the rate of survival of mice after systemic herpes simplex virus infection, although higher doses were required to give comparable effects. Combined prophylactic and therapeutic administration of interleukin-12 produced the greatest effect on survival after an otherwise lethal systemic infection. Intraperitoneal administration of interleukin-12 for 2 days before and 3 days after systemic infection with herpes simplex virus resulted in survival of 80% of the mice. These surviving mice were resistant to subsequent reinfection with herpes simplex virus. Such resistance was apparently specific for herpes simplex virus infection, since a second group of survivors succumbed to a lethal infection with murine cytomegalovirus. Infectious virus was recovered from lumbar ganglia explants dissected from survivors of prophylactic interleukin-12 therapy and cultured for 5 days in vitro, suggesting that interleukin-12 treatment did not prevent the establishment of latent herpes simplex virus infection. One action of interleukin-12 may be to enhance natural killer cell-mediated clearance of the virus. However, interleukin-12 therapy was also effective in mice carrying the beige mutation, which reduces natural killer cell lytic activity, suggesting that interleukin-12 has additional activities in vivo.     

Latex and vinyl nonsterile examination gloves: status report on laboratory evaluation of defects by physical and biological methods.

We have reported previously (H. R. Kotilainen, J. P. Brinker, J. L. Avato, and N. M. Gantz, Arch. Intern. Med. 149:2749-2753, 1989) that the quality of nonsterile examination gloves available for clinical use may be extremely variable. In view of the concern over human immunodeficiency virus and hepatitis B virus transmission to health care workers, the continuing variability of gloves available for use, and the need for a simple and safe test, we have evaluated 2,500 vinyl (five brands) and 2,000 latex (four brands) gloves by the 300-ml and the newly proposed 1,000-ml water tests and for permeability to herpes simplex virus type 1 and poliovirus type 1, respectively. While all 300-ml watertight gloves were unlikely to leak herpes simplex virus type 1 (1.3% vinyl; 0.5% latex), poliovirus was recovered much more frequently (8.9% vinyl, 6.1% latex). In all gloves that passed the 1,000-ml test, herpes simplex virus type 1 was not recovered. Poliovirus was recovered infrequently (1.4% vinyl, 1.5% latex). Preliminary analyses suggest that the 1,000-ml water test has significantly increased sensitivity over the 300-ml water test in the detection of small holes in both vinyl and latex gloves that may allow the passage of viral particles. Gloves that pass a 1,000-ml water challenge are unlikely to allow the passage of a small virus such as poliovirus. Given that human immunodeficiency virus, hepatitis B virus and herpes simplex virus type 1 are larger particles than poliovirus, gloves that pass the 1,000-ml water test theoretically could provide better protection.     

Latex and vinyl nonsterile examination gloves: status report on laboratory evaluation of defects by physical and biological methods

We have reported previously (H. R. Kotilainen, J. P. Brinker, J. L. Avato, and N. M. Gantz, Arch. Intern. Med. 149:2749-2753, 1989) that the quality of nonsterile examination gloves available for clinical use may be extremely variable. In view of the concern over human immunodeficiency virus and hepatitis B virus transmission to health care workers, the continuing variability of gloves available for use, and the need for a simple and safe test, we have evaluated 2,500 vinyl (five brands) and 2,000 latex (four brands) gloves by the 300-ml and the newly proposed 1,000-ml water tests and for permeability to herpes simplex virus type 1 and poliovirus type 1, respectively. While all 300-ml watertight gloves were unlikely to leak herpes simplex virus type 1 (1.3% vinyl; 0.5% latex), poliovirus was recovered much more frequently (8.9% vinyl, 6.1% latex). In all gloves that passed the 1,000-ml test, herpes simplex virus type 1 was not recovered. Poliovirus was recovered infrequently (1.4% vinyl, 1.5% latex). Preliminary analyses suggest that the 1,000-ml water test has significantly increased sensitivity over the 300-ml water test in the detection of small holes in both vinyl and latex gloves that may allow the passage of viral particles. Gloves that pass a 1,000-ml water challenge are unlikely to allow the passage of a small virus such as poliovirus. Given that human immunodeficiency virus, hepatitis B virus and herpes simplex virus type 1 are larger particles than poliovirus, gloves that pass the 1,000-ml water test theoretically could provide better protection.     

Effect of Persistent Fibroma Virus Infection on Susceptibility of Cells to Other Viruses

Shope fibroma virus establishes a persistent cytoplasmic infection in primary (RK) and serially cultivated (DRK(3)) rabbit kidney cells which is accompanied by a morphological alteration of the cells. The response of such cells to superinfection by other viruses was compared with that of control cells by determining plaque production and virus yield of superinfecting viruses. It was found that the growth of other poxviruses, myxoma and vaccinia, was greatly inhibited in the fibroma virus-infected cells, but that of pseudorabies and herpes simplex viruses, which are unrelated deoxyribonucleic acid viruses, was virtually unaffected. The ribonucleic acid (RNA) viruses, poliovirus 1 and coxsackievirus B1, did not produce plaques on either RK or fibroma virus-infected (F-RK) monolayers. However, the growth of several other RNA viruses, vesicular stomatitis virus, encephalomyocarditis virus, Sindbis virus, and Newcastle disease virus, was enhanced in F-RK cells. None of these latter RNA viruses produced any infectious progeny in DRK(3) cells, but they all plaqued on and produced good yields in DRK(3) cells persistently infected with fibroma virus. This phenomenon is termed facilitation. Facilitation results from the infection of DRK(3) cells by fibroma virus. Neither interference nor facilitation were due to changes in the adsorption or eclipse of the superinfecting virus.     

Live-cell analysis of a green fluorescent protein-tagged herpes simplex virus infection

Many stages of the herpes simplex virus maturation pathway have not yet been defined. In particular, little is known about the assembly of the virion tegument compartment and its subsequent incorporation into maturing virus particles. Here we describe the construction of a herpes simplex virus type 1 (HSV-1) recombinant in which we have replaced the gene encoding a major tegument protein, VP22, with a gene expressing a green fluorescent protein (GFP)-VP22 fusion protein (GFP-22). We show that this virus has growth properties identical to those of the parental virus and that newly synthesized GFP-22 is detectable in live cells as early as 3 h postinfection. Moreover, we show that GFP-22 is incorporated into the HSV-1 virion as efficiently as VP22, resulting in particles which are visible by fluorescence microscopy. Consequently, we have used time lapse confocal microscopy to monitor GFP-22 in live-cell infection, and we present time lapse animations of GFP-22 localization throughout the virus life cycle. These animations demonstrate that GFP-22 is present in a diffuse cytoplasmic location when it is initially expressed but evolves into particulate material which travels through an exclusively cytoplasmic pathway to the cell periphery. In this way, we have for the first time visualized the trafficking of a herpesvirus structural component within live, infected cells.     

Herpes simplex virus binding and entry modulate cell surface protein mobility.

Fluorescence photobleaching recovery measurements showed that herpes simplex virus type 1 attachment to target cells rapidly induced an anchorage modulation of cell surface protein mobility, an activity mediated by the cytoskeleton and associated with the multivalent attachment of other ligands (e.g., cells, lectins, or anti-immunoglobulin) to cell surfaces. The restriction in cell surface protein mobility was released concurrently with virus penetration. The effects of attachment and penetration on cell surface protein mobility and cytoskeletal function are some of the earliest cellular changes induced by herpes simplex virus infection.     

Variation in intracellular P1P4-bis(5''-adenosyl) tetraphosphate (Ap4A) in virus-infected cells.

The effect of virus infection on the intracellular concentration of the proposed stress alarmone P1P4-bis(5'-adenosyl) tetraphosphate (Ap4A) has been examined in Vero cells. Compared with exposure to 0.8 mM-Cd2+, which causes a 30-fold increase in Ap4A, infection with simian virus 40 and poliovirus causes only a 2-fold increase, whereas herpes simplex virus type 1 results in a decrease in Ap4A during the course of the infection.     

Deoxythymidine kinase induced in HeLa TK- cells by herpes simplex virus type I and type II. II. Purification and characterization.

Deoxythymidine kinase activities were induced in HeLa TK- (deoxythymidine kinase-deficient) cells infected with either herpes simplex virus type I or herpes simplex virus type II. The herpes simplex virus type I-induced enzyme was found in the cytoplasmic and nuclear fractions of the infected cells, whereas the herpes simplex type II-induced deoxythymidine kinase could only be found in the cytoplasm. Herpes simplex virus type I and II specific deoxythymidine kinases were purified by affinity column chromatography. Both purified deoxythymidine kinases retained the deoxycytidine kinase activity present in the crude preparation. The purified herpes simplex virus type I deoxythymidine kinase had a different mobility on electrophoresis, but the same sedimentation rate on a glycerol gradient as the corresponding unpurified enzyme, whereas the purified herpes simplex virus type II deoxythymidine kinase had the same mobility and sedimentation rate as the corresponding unpurified enzyme. In the presence of Mg2+ATP and dithiothreitol, herpes simplex virus type II deoxythymidine kinase was more stable than herpes simplex virus type I deoxythymidine kinase at both 45 degrees and 4 degrees. The deoxycytidine kinase activity present in the purified preparations was inactivated at the same rate as the deoxythymidine kinase activity. In the presence of the other substrate, deoxythymidine, herpes simplex virus type I deoxythymidine kinase was more stable than herpes simplex virus type II kinase. The purified herpes simplex virus type I and II deoxythymidine kinase had different activation energies when Mg2+ATP and deoxythymidine were used as substrates, but showed the same sensitivity toward ammonium sulfate inhibition.     

Isolation of a protein kinase induced by herpes simplex virus type 1

We have isolated a new cyclic AMP-independent protein kinase activity induced in HeLa cells by infection with herpes simplex virus type 1. Induction of the enzyme does not occur in cells treated with cycloheximide at the time of infection, or in cells infected with UV-inactivated herpes simplex virus type 1. The amount of enzyme induced in infected cells is dependent upon the multiplicity of infection. An enzyme with identical properties to the appearing in infected HeLa cells is also induced by herpes simplex virus type 1 in BHK cells.     

Search for inhibitors against herpes simplex virus type-I in cell extracts derived from human lymphoblastoid cell lines.

Cell extracts obtained from KB cells and 5 human lymphoblastoid cell lines including 2 from Burkitt's lymphoma (P3HR-1 and Raji), one each from nasopharyngeal carcinoma (no.223), acute lymphatic leukemia (MOLT-4) and a healthy person (NC-37) were tested for their inhibitory effects on the growth of herpes simplex virus type-1 (HSV-1) in green monkey kidney (GMK) cells by the plaque titration method. The relationship between the production of HSV-1 inhibitors and the degree of Epstein-Barr virus (EBV) genome repression in lymphoblastoid cells were also examined. Among the cell lines used P3HR-1 and no.223 cells produced a few EBV particles, Raji and NC-37 cells contained EBV genomes only, and MOLT-4 as well as KB cells were EBV genome-negative. The results revealed that P3HR-1 cell extract showed a tendency to inhibit HSV-1 growth in GMK cells but the other 4 lymphoblastoid cell lines and KB cells did not produce HSV-1 inhibitors, indicating that EBV genomes governing the formation of EBV structural antigens were not related to the production of HSV-1 growth inhibitors. The extracts from MOLT-4 cells, which are only a T lymphocyte cell line used in this study, stimulated HSV-1 growth in GMK cells significantly.     

Polysome-associated proteins in herpes simplex virus-infected cells

In the cytoplasm of eucaryotic cells, mRNA is associated with proteins. These mRNA-protein complexes, termed messenger ribonucleoprotein (mRNP) particles, are divided into two functional classes. The first class contains free (non-ribosome-associated) mRNPs which have been termed informosomes by others. The second class of mRNPs, those associated with polysomes, are actively engaged in protein synthesis and are termed polysomal mRNPs. The experiments described in this paper examined the proteins associated with polyribosomes in uninfected and herpes simplex virus type 1-infected cells. The data indicate that after infection with herpes simplex virus type 1, specific changes occur in the proteins which normally are found associated with these polysomal mRNPs. These changes include both the appearance of new and possibly virus-specific proteins and the loss of normal host-specific proteins. The relationship of these changes to the patterns of protein synthesis in these cells is also discussed.     

Role of nucleases in the origination of chromosomal disorders in virus-infected cells]

It is shown that herpes simplex virus can induce the chromosome aberrations both in cells supporting the productive infection and in non-permissive cells. In virus-infected human embryo fibroblast culture the activity of cell (lysosomal) and virus-coded DNAses is elevated. Suppression of the activity of any of the enzymes leads to decreasing the number of aberrant cells. Suppression of the activity of both DNases at the same time decreases the number of aberrant cells to a control level. In M15 cells which do not support the productive infection, the activity of only lysosomal DNase is elevated. Suppression of its activity leads to the decrease of the frequency of cells with chromosome breaks to a control level. Thus, both cells and virus-coded lytic enzymes can participate in the production of chromosome breaks in virus-infected cells. Possibly, the relative role of these enzymes may be rather different in different virus-cell systems.     

Nuclear membrane changes in herpes simplex virus-infected BHK-21 cells as seen by freeze-fracture.

The freeze-fracture technique, which produced high-resolution replicas of large internal faces of membranes, was used for an ultrastructural study of the nuclei of herpes simplex virus-infected BHK-21 cells and mock-infected controls. Crystalline arrays of viral nucleocapsids were found in the nucleoplasm of infected cells, and numerous nuclear membrane "blebs" and protrusions were observed. The numerous areas of membrane distortions were not found to contain nuclear pores. In addition, specific areas of normal protein intramembranous particles are deleted from certain areas of the nuclear membrane as a result of herpes simplex virus, type 2, infection.