Archives of Virology

Hiscox, J. A.

doi: 10.1007/s00705-001-0792-0pmid: 12111420

Summary A number of viruses and viral proteins interact with a dynamic sub-nuclear structure called the nucleolus. The nucleolus is present during interphase in mammalian cells and is the site of ribosome biogenesis, and has been implicated in controlling regulatory processes such as the cell cycle. Viruses interact with the nucleolus and its antigens; viral proteins co-localise with factors such as nucleolin, B23 and fibrillarin, and can cause their redistribution during infection. Viruses can use these components as part of their replication process, and also use the nucleolus as a site of replication itself. Many of these properties are not restricted to any particular type of virus or replication mechanism, and examples of these processes can be found in DNA, RNA and retroviruses. Evidence suggests that viruses may target the nucleolus and its components to favour viral transcription, translation and perhaps alter the cell cycle in order to promote virus replication. Autoimmunity to nucleolin and fibrillarin have been associated with a number of diseases, and by targeting the nucleolus and displacing nucleolar antigens, virus infection might play a role in the initiation of these conditions.

Kwofie, T. B.; Miura, T.; Ibuki, K.; Enose, Y.; Suzuki, H.; Ui, M.; Kuwata, T.; Hayami, M.

doi: 10.1007/s00705-002-0811-9pmid: 12111421

Monkeys that have been vaccinated with nef -deleted SHIVs were either fully or partially protected against challenge with acute pathogenic SHIV-89.6 P. Viruses isolated from these vaccinated monkeys were all found to be the 89.6 P challenge virus using PCR amplification and restriction enzyme analysis of the env region of the viruses. Analysis of the 3′-end of the env region and 5′-half of the nef region using a heteroduplex mobility assay revealed that the parental 89.6 P and re-isolated viruses from unvaccinated 89.6 P-infected monkeys had quite an abundant and similar heterogeneous quasispecies population. In contrast, the viruses isolated from the vaccinated monkeys had different and fewer quasispecies indicating a selective immune pressure in the vaccinated monkeys. The in vitro replication of the viruses isolated from the vaccinated monkeys in human and macaque peripheral blood mononucular cells (PBMCs) as well as in established cell lines such as M8166 and HSC-F cells, were slow and delayed when compared to the parental 89.6 P and re-isolated viruses from unvaccinated 89.6 P-infected monkeys. Further comparison revealed that in HSC-F cells the viruses from vaccinated monkeys again showed delayed and weak CD4 + cell down-modulation as well as having little or no effect on cell growth or cell viability on HSC-F cells and monkey PBMC. Thus we noticed that these re-isolated 89.6 P viruses from the vaccinated monkeys had changed or had been selected for low pathogenic viruses in the monkeys. This suggests that though the vaccination did not completely prevent the replication of the challenge virus in the monkeys it did contain the challenge virus by suppressing the pathogenic variants. This further enhances the prospects of this nef -deleted SHIV as the bases for effective anti-HIV vaccine candidates.

Parquet, M. C.; Kumatori, A.; Hasebe, F.; Mathenge, E. G. M.; Morita, K.

doi: 10.1007/s00705-002-0806-6pmid: 12111422

Apoptosis is a highly regulated process of cellular self-destruction with diverse functions in multicellular organisms. It is known to be one of the mechanisms of viral pathogenesis. St. Louis encephalitis virus (SLEV), an arthropod-borne flavivirus, causes encephalitis disease of varying severity mostly in North America and in some regions of South America. This virus induces cytopathic effects in vertebrate cell lines, however, the mechanism by which this occurs is yet to be elucidated. SLEV induced cytopathic effects in K562 cells, a human mononuclear cell line, and in Neuro 2a cells, a mouse neuroblastoma cell line. SLEV-infected K562 and Neuro 2a cells underwent apoptotic cell death, whereas neither the cells inoculated with UV-inactivated virus nor the mock-infected cells developed cytopathic effects. The gene expression of regulators of apoptosis was investigated in K562 cells. A rise in the expression of the pro-apoptotic bax gene was detected specifically in the SLEV-infected K562 cells. These findings suggest that up-regulation of bax mRNA is correlated with cytopathic effects in SLEV-infected K562 cells.

Kuwata, T.; Takemura, T.; Takehisa, J.; Miura, T.; Hayami, M.

doi: 10.1007/s00705-002-0803-9pmid: 12111423

Chimeric simian and human immunodeficiency viruses (SHIVs) are useful for investigating the pathogenicity of human immunodeficiency virus (HIV-1) and to develop an anti-HIV-1 vaccine. We attempted to construct SHIVs containing Env from various subtypes, because almost all SHIVs which have been reported so far have Env from HIV-1 that belongs to subtype B. Two infectious SHIVs containing Env from two strains of HIV-1, CMR304 and CMR306, which belong to subtype F and A, respectively, were newly obtained. These SHIVs essentially showed a coreceptor usage and a neutralization pattern that were similar to those of the parental HIV-1s. In macaque PBMC, SHIVcmr304 replicated with kinetics similar to that of prototypic SHIV-NM-3rN with HIV-1 NL 432 Env, but SHIVcmr306 replicated poorly. Inoculation of four rhesus macaques with SHIVcmr304 resulted in an increase of plasma viral load in all the macaques, though viral RNA copies were 100-fold lower than that in the infection with NM-3rN. This SHIV containing Env from HIV-1 subtype F will be a valuable source for the analysis of HIV-1 subtype F and the evaluation of vaccine candidates as a genetically divergent challenge virus.

Becher, P.; König, M.; Müller, G.; Siebert, U.; Thiel, H.-J.

doi: 10.1007/s00705-002-0804-8pmid: 12111424

Summary A disease outbreak characterized by lesions of the skin and mucosa of the oral cavity was recognized in harbor seals (Phoca vitulina) from the German North Sea. Using electron microscopy typical parapoxvirus particles were observed. The presence of parapoxvirus was confirmed by PCR and nucleotide sequencing of part of the putative major envelope protein coding gene. Comparative sequence analysis revealed that the virus from seal is significantly different from the established parapoxvirus species Orf virus, Bovine papular stomatitis virus, Pseudocowpox virus, and Parapoxvirus of red deer in New Zealand. The results of our analysis provide evidence for inclusion of the seal parapoxvirus as member of a separate species within the genus Parapoxvirus.

Miyanishi, M.; Roh, S. H.; Yamamiya, A.; Ohsato, S.; Shirako, Y.

doi: 10.1007/s00705-002-0798-2pmid: 12111425

Soil-borne wheat mosaic virus (SBWMV), the type species of the genus Furovirus , has a plus-sense bipartite RNA genome. Japanese and US strains of SBWMV are genetically distantly related, despite their biologically identical properties. Here we report formation of a pseudorecombinant virus consisting of RNA1 from a Japanese strain and RNA2 from a US strain, using infectious in vitro transcripts for both strains. Full-length infectious cDNA clones for a Japanese strain were previously constructed (Yamamiya and Shirako (38)). For RNA1 of a US strain, due to instability of full-length cDNA clones in Escherichia coli cells, it was necessary to prepare a full-length template DNA for in vitro transcription by combining overlapping 5′-terminal and 3′-terminal cDNAs individually cloned in two plasmids, whereas for RNA2 a full-length cDNA clone was the template. For infectivity assays, Chenopodium quinoa , a local lesion host, and wheat, a systemic host, were used. A mixture of Japanese RNA1 transcripts and US RNA2 transcripts caused formation of local lesions on C. quinoa leaves and systemic infection to wheat plants. The nucleotide sequence of the progeny viral RNA2 was identical to that of the US RNA2. The reciprocal combination was not infectious to either host. These results confirm that the Japanese and US SBWMV are genetically distantly related strains belonging to a single species.

Kroeger, M. A.; McMinn, P. C.

doi: 10.1007/s00705-002-0809-3pmid: 12111426

We report on the development and characterisation of a recombinant Murray Valley encephalitis virus (MVE) envelope glycoprotein expression system that results in the secretion of subviral particles (SVPs) upon transfection of the murine fibroblast (COS-7) cell line. Initially, aspects of the physical and antigenic structure of cell-associated and secreted forms of the MVE envelope glycoproteins (prM and E) are presented. We then show that BALB/c mice inoculated with SVPs purified from pcDNA 3 -prM/E-transfected COS-7 cell supernatants are protected from lethal challenge with the virulent prototype strain MVE-1-51 and that this protection correlates with the development of a neutralising humoral immune response by the host. By contrast, prior immunisation with cell-associated, recombinant MVE envelope glycoproteins did not protect mice from challenge with MVE-1-51 and this was associated with the development of antibody that was unable to neutralise virus infectivity in vitro. These studies demonstrate that SVPs derived from the in vitro expression of recombinant MVE prM and E genes are an effective candidate vaccine for the prevention of encephalitis in the mouse model.

Nath, N.; Mathur, S.; Dasgupta, I.

doi: 10.1007/s00705-002-0801-ypmid: 12111427

The complete genomic sequences of two geographically distinct isolates of rice tungro bacilliform virus (RTBV) from India were determined. Both the sequences showed equal divergence from previously reported Southeast Asian isolates. Numerous insertions, deletions and substitutions, mostly in the intergenic regions, were found. The genome sizes were 7907 and 7934 bp respectively, 95 and 68 residues short of an infectious clone reported earlier. Between them, both the isolates showed high homology all along the genome, except for a 30-nucleotide insertion/deletion close to the 3′ end of ORF III in one of them. Both the isolates indicated an unconventional start codon in ORF I, similar to the type isolate. In addition, as novel features, both the Indian isolates showed an unconventional start codon for ORF IV. Considering the low amounts of genome variability noticed in other RTBV isolates, the Indian isolates show that they have diverged sufficiently from the rest and should be considered belonging to a distinct strain.

Tang, J.; Wang, M.; Qiu, J.; Wu, D.; Hu, W.; Shi, B.; Hu, Y.; Li, J.

doi: 10.1007/s00705-002-0797-3pmid: 12111428

Summary To investigate the mechanisms that human cytomegalovirus (HCMV) can vertically transmit from the placenta of mice to infect their offspring in the central nervous system (CNS) and cause congenital anomalies, and in order to provide basic research for preparing HCMV vaccine, we have developed a new type of mouse model of HCMV congenital CNS infection. Pure strain mice were propagated after being infected with HCMV. Then the degree of infection by HCMV to offspring was determined. The experiment shows that in the infection groups the mortality of fetal mice and the fatality of neonatal mice in one week are higher than that of the control groups (P ≤ 0.05). At the same time we investigated the CNS of fetus’s mice whose mothers were infected by HCMV. Our results showed: 1. The virus was successfully isolated from their cerebral cortex. 2. The signal of HCMV hybridization print was found in their nervous cell through in situ hybridization. 3. Especially human herpes virus-like particles and inclusion bodies in the plasm of nerve cell were found in the tissue of their brain under the electron microscope. This new type of mouse model of HCMV inherent CNS infection will help prepare HCMV vaccine and research HCMV congenital infection in CNS.

Gambaryan, A.; Webster, R.; Matrosovich, M.

doi: 10.1007/s00705-002-0796-4pmid: 12111429

H5, H7, and H9 subtype influenza viruses in land-based poultry often differ from viruses of wild aquatic birds by deletions in the stalk of the neuraminidase, by the presence of additional carbohydrates on the hemagglutinin, and by occasional changes in the receptor specificity. To test whether these differences could reflect distinctions between the virus receptors in different avian species, we compared the binding of duck, chicken and human influenza viruses to cell membranes and gangliosides from epithelial tissues of duck, chicken and African green monkey. Human viruses bound to cell membranes of monkey and chicken but not to those of duck, suggesting that chicken cells unlike duck cells contain Sia(α2-6)Gal-terminated receptors recognized by human viruses. Duck virus bound to gangliosides with short sugar chains that were abundant in duck intestine. Human and chicken viruses did not bind to these gangliosides and bound more strongly than duck virus to gangliosides with long sugar chains that were found in chicken intestinal and monkey lung tissues. Our data suggest that the spectrum of sialylglycoconjugates which can serve as influenza virus receptors in chicken is more similar to the spectrum of receptors in the respiratory epithelia of monkey than to that in the epithelial tissues of duck. This notion could explain the recent emergence of avian H9N2 virus lineage with human virus-like receptor specificity and emphasizes the role of the chicken as a potential intermediate host for the transmission of viruses from aquatic birds to humans.