Antigenic relatedness between arenaviruses defined at the epitope level by monoclonal antibodies

Several arenaviruses, chiefly Lassa virus (LASV) and Junin virus in West Africa and Argentina, respectively, cause hemorrhagic fever (HF) disease in humans that is associated with high morbidity and significant mortality. The investigation of antiviral strategies to combat HF arenaviruses is hampered by the requirement of biosafety level 4 (BSL-4) facilities to work with these viruses. These biosafety hurdles could be overcome by the use of recombinant single-cycle infectious arenaviruses. To explore this concept, we have developed a recombinant lymphocytic choriomeningitis virus (LCMV) (rLCMV⌬GP/GFP) where we replaced the viral glycoprotein (GP) with the green fluorescent protein (GFP). We generated high titers of GP-pseudotyped rLCMV⌬GP/GFP via genetic trans complementation using stable cell lines that constitutively express LCMV or LASV GPs. Replication of these GP-pseudotyped rLCMV⌬GP/GFP viruses was restricted to GP-expressing cell lines. This system allowed us to rapidly and reliably characterize and quantify the neutralization activities of serum antibodies against LCMV and LASV within a BSL-2 facility. The sensitivity of the GFP-based microneutralization assay we developed was similar to that obtained with a conventionally used focus reduction neutralization (FRNT) assay. Using GP-pseudotyped rLCMV⌬GP/GFP, we have also obtained evidence supporting the feasibility of this approach to identify and evaluate candidate antiviral drugs against HF arenaviruses without the need of BSL-4 laboratories.

Section: Resultsmentioning

confidence: 74%

Use of Single-Cycle Infectious Lymphocytic Choriomeningitis Virus To Study Hemorrhagic Fever Arenaviruses

Rodrigo

Torre

Martínez-Sobrido

2011

“…The protection afforded by the Mopeia virus from southern Africa certainly supports the idea that broad protection is achievable and desirable, particularly since some Nigerian strains may induce more severe and fatal illnesses than strains from further west (19,23,35). Monoclonal antibody mapping and molecular studies of the glycoproteins of African arenaviruses show a conserved B-cell epitope on G2 in all of the known African arenaviruses, including Mopeia and most South American arenaviruses (33).…”

Section: Single Administration Of a Vaccine Expressing The Full-lengthmentioning

confidence: 73%

Effective Vaccine for Lassa Fever

Fisher‐Hoch

Hutwagner²,

Brown

et al. 2000

Self Cite

186

206

Lassa fever has been estimated to cause 5,000 deaths annually in West Africa. Recently, war in the zone where Lassa fever is hyperendemic has severely impeded control and treatment. Vaccination is the most viable control measure. There is no correlation between antibody levels and outcome in human patients, and inactivated vaccines produce high titers of antibodies to all viral proteins but do not prevent virus replication and death in nonhuman primates. Accordingly, we vaccinated 44 macaques with vaccinia virus-expressed Lassa virus structural proteins separately and in combination, with the object of inducing a predominantly TH1-type immune response. Following Lassa virus challenge, all unvaccinated animals died (0% survival). Nine of 10 animals vaccinated with all proteins survived (90% survival). Although no animals that received full-length glycoprotein alone had a high titer of antibody, 17 of 19 survived challenge (88%). In contrast, all animals vaccinated with nucleoprotein developed high titers of antibody but 12 of 15 died (20% survival). All animals vaccinated with single glycoproteins, G1 or G2, died, but all those that received both single glycoproteins (G1 plus G2) at separate sites survived, showing that both glycoproteins are independently important in protection. Neither group had demonstrable antibody levels prior to challenge. We demonstrate that in primates, immune responses to epitopes on both glycoproteins are required to protect against lethal challenge with Lassa virus without having untoward side effects and that this protection is likely to be primarily cell mediated. We show that an effective, safe vaccine against Lassa virus can and should be made and that its evaluation for human populations is a matter of humanitarian priority.Lassa virus is endemic in rural West Africa. The prevalence of antibody to Lassa virus ranges from 5% in Guinea and 15 to 20% in Sierra Leone and Liberia to over 20% in Nigeria (7,30). Lassa fever has been estimated to cause from 100,000 to 300,000 infections a year and several thousand deaths (30). The fatality rate for hospitalized patients is about 17%, but in certain groups of patients, such as pregnant women in their third trimester, more than 30% may die, and fetal or neonatal loss is about 88% (34). Deafness is a common complication of Lassa fever, affecting as many as 15% of patients and rendering an estimated 1 to 2% of the population hearing impaired in areas with high rates of infection (11). Treatment with intravenous ribavirin has been shown to be effective; however, it is not widely available in the areas where the disease is endemic and must be administered in the first week of illness for optimal efficacy (28). Recently, social and economic conditions have deteriorated in areas of high endemicity of eastern Sierra Leone and Liberia, and incidence and mortality have increased (R. Allan, R. Ladbury, K. Skinner, and S. Mardel, Abstr. Int. Conf. Emerg. Infect. Dis., abstr. 16, p. 21, 1998).Lassa virus, an arenavirus, exhibits persistent, asymptomat...

“…Proteins were electrophoretically separated on 4% to 12% NuPAGE (Invitrogen) gels and transferred to a nitrocellulose membrane. The membranes were blocked with buffer containing Tris-buffered saline and 0.1% Tween 20 with 5% nonfat dry milk for 1 h and then probed overnight at 4°C with anti-G2 monoclonal antibodies (MAbs) (43). Membranes were developed using horseradish peroxidase-conjugated secondary antibodies and enhanced chemiluminescence.…”

Section: Methodsmentioning

confidence: 99%

Reverse Genetics Generation of Chimeric Infectious Junin/Lassa Virus Is Dependent on Interaction of Homologous Glycoprotein Stable Signal Peptide and G2 Cytoplasmic Domains

Albariño

Bird

Chakrabarti

et al. 2011

The Arenaviridae are a diverse and globally distributed collection of viruses that are maintained primarily by rodent reservoirs. Junin virus (JUNV) and Lassa virus (LASV) can both cause significant outbreaks of severe and often fatal human disease throughout their respective areas of endemicity. In an effort to improve upon the existing live attenuated JUNV Candid1 vaccine, we generated a genetically homogenous stock of this virus from cDNA copies of the virus S and L segments by using a reverse genetics system. Further, these cDNAs were used in combination with LASV cDNAs to successfully generate two recombinant Candid1 JUNV/LASV chimeric viruses (via envelope glycoprotein [GPC] exchange). It was found that while the GPC extravirion domains were readily exchangeable, homologous stable signal peptide (SSP) and G2 transmembrane and cytoplasmic tail domains were essential for correct GPC maturation and production of infectious chimeric viruses. The switching of the JUNV and LASV G1/G2 ectodomains within the Candid1 vaccine background did not alter the attenuated phenotype of the vaccine strain in a lethal mouse model. These recombinant chimeric viruses shed light on the fundamental requirements of arenavirus GPC maturation and may serve as a strategy for the development of bivalent JUNV and LASV vaccine candidates.