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PubMed2002

Mode of inactivation of arenaviruses by disulfide-based compounds.

Several disulfide-based compounds, including intermolecular aromatic disulfides of the type Ph-S-S-Ph and dithianes with the sulfur atoms tethered in a ring structure, have shown effective inhibitory activity against the arenaviruses Junin (JUNV), agent of Argentine hemorrhagic fever, and Tacaribe (TCRV). These compounds showed a strong virucidal effect with inactivating concentration 50% (IC(50)) values in the range 0.6-5.0 microM, and also were effective to reduce virus yields from infected cells. The mode of inactivating action of two active compounds, the aromatic bis disulfide NSC20625 and the dithiane NSC624152, was further studied. Both compounds were able to inactivate arenaviruses after a few minutes of direct contact with virions, in a concentration- and time-dependent manner. The ability of drug-treated virus to perform several steps of the replication cycle was analyzed. The killed virus particles were found to bind and enter to Vero cells with the same efficacy as infectious native virions, but the ability of inactivated virions to synthesize viral proteins in Vero cells was abolished. Thus, treatment of JUNV and TCRV with these compounds destroyed virion infectivity, generating particles which entered the host cell but were unable to complete the viral biosynthetic processes.

Animals↗
PubMed2003

Arenaviruses other than Lassa virus.

The family Arenaviridae includes 23 viral species, of which 5 can cause viral hemorrhagic fevers with a case fatality rate of about 20%. These five viruses are Junin, Machupo, Guanarito, Sabia and Lassa virus, the manipulation of which requires biosafety level 4 facilities. They are included in the Category A Pathogen List established by the Center for Disease Control and Prevention that groups agents with the greatest potential for adverse public health impact and mass casualties whether a situation characterized by a ill-intentioned abuse of natural or engineered arenavirus would be encountered. The aims of this article are to (i) summarize the current situation; (ii) provide information to help anticipating the effects to be expected in such a situation; and to (iii) emphasize the need for fundamental research to allow the development of diagnostic, prevention and therapeutic tools as countermeasures to weaponized arenaviruses.

Animals↗
PubMed2001

Arenavirus nucleocapsid protein displays a transcriptional antitermination activity in vivo.

RNA polymerase pausing and transcriptional antitermination regulates gene activity in several systems. In arenavirus infected cells the switch from transcription to replication is subjected to a hairpin-dependent termination and requires protein synthesis to bypass this signal. The transcriptional antitermination control by Junín virus nucleocapsid protein N, has been demonstrated in vivo by infecting BHK-21 cells expressing this viral protein in the presence of translation inhibitors. This is the first demonstration in vivo of a transcriptional antitermination control in arenavirus-infected cells.

Animals↗
PubMed2005

Hantavirus and arenavirus antibody prevalence in rodents and humans in Trentino, Northern Italy.

The spatial and temporal distribution of hantavirus and arenavirus antibody-positive wild rodents in Trentino, Italy, was studied using immunofluorescence assays (IFA) in two long-term sites trapped in 2000-2003, and six other sites trapped in 2002. The overall hantavirus seroprevalence in the bank voles, Clethrionomys glareolus (n=229) screened for Puumala virus (PUUV) antibodies was 0.4%, and that for Apodemus flavicollis mice (n=1416) screened for Dobrava virus (DOBV) antibodies was 0.2%. Antibodies against lymphocytic choriomeningitis virus (LCMV) were found in 82 (5.6%) of the 1472 tested rodents; the seroprevalence being 6.1% in A. flavicollis (n=1181), 3.3% in C. glareolus (n=276), and 14.3% in Microtus arvalis (n=7). Of the serum samples of 488 forestry workers studied by IFA, 12 were LCMV-IgG positive (2.5%) and one DOBV-IgG positive (0.2%), however, the latter could not be confirmed DOBV-specific with a neutralization assay. Our results show a widespread distribution but low prevalence of DOBV in Trentino, and demonstrate that the arenavirus antibodies are a common finding in several other rodent species besides the house mouse.

Adult↗
PubMed1989

Junin virus monoclonal antibodies: characterization and cross-reactivity with other arenaviruses.

Twenty-one monoclonal antibodies reactive with Junin virus structural proteins were produced and characterized. Using radioimmunoprecipitation and Western blot assays, 13 were found to react with the nucleoprotein, seven with the surface glycoprotein and one failed to react, but showed a fluorescent antibody staining pattern consistent with other glycoprotein-specific antibodies. In radioimmunoprecipitation assays, glycoprotein-specific monoclonal antibodies reacted not only with the 35K structural glycoprotein, but also with what is presumed to be the glycoprotein precursor. Four of seven glycoprotein-specific antibodies neutralized Junin virus to high titres. Cross-reactivity with other arenaviruses was found to be restricted to nucleoprotein-specific monoclonal antibodies and occurred only with New World arenaviruses. Cross-reactivity also shows the Junin virus to be most closely related to Machupo and Tacaribe viruses.

Animals↗
PubMed2002

Bear Canyon virus: an arenavirus naturally associated with the California mouse (Peromyscus californicus).

Thirty-four rodents captured in southern California were studied to increase our knowledge of the arenaviruses indigenous to the western United States. An infectious arenavirus was isolated from 5 of 27 California mice but none of the 7 other rodents. Analyses of viral nucleocapsid protein gene sequence data indicated that the isolates from the California mice are strains of a novel Tacaribe serocomplex virus (proposed name "Bear Canyon") that is phylogenetically most closely related to Whitewater Arroyo and Tamiami viruses, the only other Tacaribe serocomplex viruses known to occur in North America. The discovery of Bear Canyon virus is the first unequivocal evidence that the virus family Arenaviridae is naturally associated with the rodent genus Peromyscus and that a Tacaribe serocomplex virus occurs in California.

Animals↗
PubMed1996

Characterization of Oliveros virus, a new member of the Tacaribe complex (Arenaviridae: Arenavirus).

Oliveros virus is an agent isolated in cell culture from Bolomys obscurus (Rodentia, Muridae, Sigmodontinae) captured on the central Argentine pampa. Oliveros virus was shown to be related to members of the Tacaribe complex of the family Arenaviridae by immunofluorescent antibody (IFA) tests, electrophoretic pattern of viral proteins, and morphology as observed by electron microscopy. It was distinct from 12 other arenaviruses by a combination of plaque-reduction neutralization tests, comparison of endpoint titers among cross-IFA tests, and comparison of viral RNA sequence data. This agent is the third new arenavirus from South America described within the last three years.

Animals↗
PubMed1991

Patterns of transient expression of the arenavirus nucleocapsid protein gene in transfected cells.

The cloned genes for the nucleocapsid proteins N of Junín and LCM (lymphocytic choriomeningitis) arenaviruses were inserted into the SV40-derived expression vector designated pKG4. When BHK-21 (baby hamster kidney fibroblasts) and CV-1 (African green monkey kidney fibroblasts) cell lines were transfected using these constructions, the transient expression yielded a polypeptide that could not be distinguished either by size nor by immunoreactivity from the N protein synthesized during the viral infection. The immunofluorescence analysis showed a pattern of intracellular localization similar to that observed in virus infected cells, i.e. varying from a diffuse cytoplasmic staining to granules, either distributed throughout the cytoplasm or concentrated in the perinuclear region. The association of the N protein with basophilic granules is similar to that observed in the cytopathic effect caused by arenaviruses, and could be related to the physicochemical properties of this polypeptide containing numerous basic amino acid sequences, that would allow for the interaction with cellular RNAs.

Animals↗
PubMed1975

Antigenic properties of the arenaviruses.

Arenaviruses are known to show antigenic relationships in the complement-fixation (CF) and fluorescent antibody tests but not in the neutralization test. The humoral response to some of the arenaviruses is characterized by a dissociation between the antibodies determined by the CF test and those determined by the neutralization test and also by its late appearance following natural infection. Investigations are reported showing that, as regards the CF test, Junin, Machupo, Amapari, and Tacaribe viruses are closely related, while LCM and Lassa viruses are distantly related to each other and to the remaining viruses in the group. Studies by agar gel diffusion and precipitation have shown complete specificity except among viruses that are very closely related in the CF test. Observations with sera from persons infected with Lassa fever virus show that CF antibodies rarely appear before the 18th day after onset; they can persist, with diminishing titres, for up to 6 years.

Animals↗
PubMed2004

Mucosal arenavirus infection of primates can protect them from lethal hemorrhagic fever.

Arenaviruses are transmitted from rodents to human beings by blood or mucosal exposure. The most devastating arenavirus in terms of human disease is Lassa fever virus, causing up to 300,000 annual infections in West Africa. We used a model for Lassa fever in which Rhesus macaques were infected with a related virus, lymphocytic choriomeningitis virus (LCMV). Our goals were to determine the outcome of infection after mucosal inoculation and later lethal challenge, to characterize protective immune responses, and to test cross-protection between a virulent (LCMV-WE) and an avirulent (LCMV-ARM) strain of virus. Although intravenous infections in the monkey model were uniformly lethal, intragastric infections recapitulated the spectrum of clinical outcomes seen in human exposure to Lassa fever virus: death, recovery from disease, and most often, subclinical infection. Plaque neutralization, ELISA, lymphocyte proliferation, and chromium-release assays were used to monitor humoral and cellular immune responses. Cross protection between the two strains was observed. The three out of seven monkeys that experienced protection were also the three with the strongest cell-mediated immunity.

Animals↗
PubMed1989

Early events in arenavirus replication are sensitive to lysosomotropic compounds.

Lysosomotropic compounds (ammonium chloride, chloroquine, amantadine, monensin) effectively inhibited the replication of Pichinde, Mopeia, and Lassa viruses in BHK-21 and Vero cells. The inhibitory effect was dependent upon the time of drug addition and was most effective when the drugs were added 1 h before the viral adsorption. The drugs had no direct effect on the infectious viruses nor on adsorption of the arenaviruses. These results suggest that the arenaviruses enter cells by adsorptive endocytosis with the participation of acidic intracellular vesicules.

Adsorption↗
PubMed1981

Enzyme-linked immunosorbent assay for detection of arenaviruses.

Conditions for ELISA by using IgG linked with horseradish peroxidase have been developed for the detection of 6 arenaviruses (Machupo, Junin, Tacaribe, Amapari, LCM and Tamiami). This method allows the detection of arenavirus antigens in various materials; organs and blood in affected animals and infected cell culture fluids. It shows higher sensitivity and allows an earlier detection of virus-specific antigens as compared with the CF test.

Animals↗
PubMed1989

Nucleotide sequence of the Lassa virus (Josiah strain) S genome RNA and amino acid sequence comparison of the N and GPC proteins to other arenaviruses.

The complete nucleotide sequence of the S genome RNA of the Josiah strain of Lassa virus was determined from cloned cDNA. The S RNA is 3402 nucleotides long with a calculated molecular weight of 1.09 x 10(6) Da. The nucleotide base composition is 26.84% adenine, 21.40% guanine, 22.75% cytosine, and 29.01% uridine. The 5' and 3' terminal nucleotide sequences are conserved and complimentary for 19 nucleotides, the nucleoprotein and glycoprotein genes are arranged in ambisense coding strategy, and the intergenic region contains an inverted complimentary sequence, as do all other arenavirus S RNAs characterized to date. Amino acid sequence comparisons between the nucleoproteins and glycoproteins of the Josiah and Nigerian (N sequences only) strains of Lassa virus, the WE and ARM strains of lymphocytic choriomeningitis virus (LCMV), Tacaribe, and Pichinde viruses are presented. These findings reveal that the G2 envelope glycoprotein is more conserved among different arenaviruses than the internal nucleoprotein.

Amino Acid Sequence↗
PubMed1991

Sequence analysis of the S RNA of the African arenavirus Mopeia: an unusual secondary structure feature in the intergenic region.

Mopeia virus is an apparently nonpathogenic African arenavirus which can protect animals from subsequent challenge by the closely related Lassa virus. As a step toward understanding these differences in pathogenicity and the means by which Mopeia virus infection can protect against subsequent Lassa virus infection, cDNA clones corresponding to 3419 nucleotides of Mopeia virus S RNA were isolated and sequenced. Two open reading frames, encoding the glycoprotein precursor (GPC) and nucleocapsid (N) proteins, were located in the ambisense arrangement characteristic of the arenaviruses. Comparison of the amino acid sequences of the translation products with those of two Lassa virus strains showed considerable conservation, with 74 and 80% identity for the two glycoproteins G1 and G2, and 74% identity for the N protein. The putative dibasic site of GPC cleavage (R-R) was conserved, as were the potential N-linked glycosylation sites. A striking difference between Mopeia virus and Lassa virus was identified in the noncoding intergenic region. Instead of the single hairpin structure formed by base-pairing of complementary sequences which is usually found, the Mopeia virus S RNA has the potential to form two hairpins. These hairpins were similar in sequence and may have been formed in a duplication event during RNA replication. The possible contribution of this secondary structure feature to differences in pathogenicity between Mopeia and Lassa viruses is discussed.

Amino Acid Sequence↗
PubMed1992

Generation of reassortants between African arenaviruses.

Lassa (LAS) and Mopeia (MOP) viruses are African arenaviruses which are carried by wild rodents and occasionally transferred to humans. In humans and nonhuman primates, Lassa causes mortality in 60% of untreated cases, whereas Mopeia does not cause mortality and has been known to protect monkeys from lethal challenge with Lassa. These two African arenaviruses also differ in their lethality for suckling outbred mice and in their plaque sizes under agar overlay. MOP virus induces small plaques and lethal infection after intracerebral (ic) inoculation. In contrast, LAS inoculation does not kill mice and the virus induces large plaques. After coinfection of Vero cells with LAS and MOP viruses some phenotypic reassortants which produced small plaques and were not lethal for outbred mice were isolated and plaque-purified. Dot-blot hybridization using LAS and MOP cDNA probes specific for L and S RNA segments revealed a genotype consisting of the L RNA of MOP and the S RNA of LAS (MOP/LAS reassortant). Adoptive transfer experiments demonstrated an ability of immune splenocytes from CBA mice intraperitoneally infected with the MOP/LAS reassortants to protect recipient mice against lethal disease after ic inoculation with LAS virus.

Animals↗
PubMed1992

Selective inhibition of arthropod-borne and arenaviruses in vitro by 3'-fluoro-3'-deoxyadenosine.

A novel nucleoside analog, 3'-fluoro-3'-deoxyadenosine (3'F3'dAdo), was evaluated for antiviral activity against several arthropod-borne and arenaviruses in Vero cell culture. The following 50% inhibitory concentrations (EC50) of virus plaque formation were obtained against the test viruses: Semliki Forest (10.3 microM) and Venezuelan equine encephalitis (5.3 microM) alphaviruses, lymphocytic choriomeningitis (7.7 microM) and Pichinde (greater than 32 microM) arenaviruses, Punta Toro (greater than 32 microM) and San Angelo (1.6 microM) bunyaviruses, banzi flavivirus (4.0 microM), and Colorado tick fever orbivirus (0.6 microM). By comparison, the broad-spectrum antiviral agent ribavirin was active against lymphocytic choriomeningitis (18 microM), Pichinde (24 microM), Punta Toro (114 microM), and San Angelo (99 microM) viruses, but was less active against the other 4 viruses (greater than 200 microM). Vero cell proliferation and thymidine and uridine incorporation into replicating Vero cells were inhibited by 50% with 3'F3'dAdo concentrations of 36, 45, and 32 microM, respectively. In virus yield reduction assays, increasing the multiplicity of infections of Semliki Forest and Venezuelan equine encephalitis viruses reduced the inhibitory activity of 3'F3'dAdo. Using the same assay, 3'F3'dAdo was found to enhance Punta Toro virus replication up to 5-fold relative to the untreated control. By adding the nucleoside transport inhibitor nitrobenzylthioinosine (100 microM) to the culture medium, antiviral activity against the two alphaviruses was eliminated, indicating that 3'F3'dAdo uses the nucleoside transport system for cell entry. When actinomycin D (5 microM) was used to greatly suppress cellular RNA synthesis in Semliki Forest virus-infected and uninfected cells, 3'F3'dAdo preferentially inhibited viral RNA synthesis. The results of these studies indicate 3'F3'dAdo is a selective inhibitor of most of the viruses tested and should be a promising candidate for in vivo evaluations.

Animals↗
PubMed1987

Molecular structure and early events in the replication of Tacaribe arenavirus S RNA.

Tacaribe arenavirus S RNA was cloned and analysis of its nucleotide sequence revealed two open reading frames of significant size, one in the virus-sense strand, the other in the virus-complementary strand. The predicted amino acid sequences of the two reading frames were compared with the predicted primary structures of the nucleoprotein (N) and glycoprotein precursor (GPC) of LCM, Pichinde and Lassa viruses. The results indicated a high degree of homology between the proteins of similar properties. It was also found that in Tacaribe virus-infected cells a subgenomic viral-sense GPC RNA and a subgenomic viral-complementary N RNA are synthesized in addition to the full length viral (v) RNA and viral complementary (vc) RNAs. These results support the conclusion that in Tacaribe virus--as in Pichinde and lymphocytic choriomeningitis arenavirus-S RNA encodes the viral N and GPC proteins and has an 'ambisense' coding strategy. Analysis of the S-derived RNA species at early times post-infection in cells incubated with or without inhibitors of protein synthesis indicated that for primary transcription of the N mRNA, protein synthesis is not required; whereas synthesis of the vc RNA, GPC mRNA and v RNA does require protein synthesis to take place.

Amino Acid Sequence↗
PubMed1991

Nucleotide sequence of the S RNA of Lassa virus (Nigerian strain) and comparative analysis of arenavirus gene products.

The nucleotide sequence of the small (S) genomic RNA of Lassa virus (strain GA391, of Nigerian origin) has been determined. The RNA has features which conform to those seen in most other arenavirus S RNAs which have been characterised, including conserved terminal sequences, an ambisense arrangement of the coding regions for the precursor glycoprotein (GPC) and nucleocapsid (N) proteins and an intergenic region capable of forming a base-paired "hairpin" structure. Comparison of the nucleotide sequence with that of the Josiah strain of Lassa virus (from Sierra Leone) reveals considerable nucleotide divergence in the third base of codons in the reading frames of all three proteins, although the resulting protein sequences are highly conserved, with 92, 94 and 91% identical residues for the mature glycoproteins G1 and G2 and the N protein, respectively. Sequence alignments of the available arenavirus structural proteins and dendrograms summarising the relationships between the viral proteins are presented.

Amino Acid Sequence↗