Hepatitis E Virus (HEV) Genotype 3 Infection of Human Liver Chimeric Mice as a Model for Chronic HEV Infection

Abstract

Genotype 3 (gt3) hepatitis E virus (HEV) infections are emerging in Western countries. Immunosuppressed patients are at risk of chronic HEV infection and progressive liver damage, but no adequate model system currently mimics this disease course. Here we explore the possibilities of in vivo HEV studies in a human liver chimeric mouse model (uPA ؉/؉ Nod-SCID-IL2R␥ ؊/؊ ) next to the A549 cell culture system, using HEV RNA-positive EDTA-plasma, feces, or liver biopsy specimens from 8 immunocompromised patients with chronic gt3 HEV. HEV from feces-or liver-derived inocula showed clear virus propagation within 2 weeks after inoculation onto A549 cells, compared to slow or no HEV propagation of HEV RNA-positive, EDTA-plasma samples. These in vitro HEV infectivity differences were mirrored in human-liver chimeric mice after intravenous (i.v.) inoculation of selected samples. HEV RNA levels of up to 8 log IU HEV RNA/gram were consistently present in 100% of chimeric mouse livers from week 2 to week 14 after inoculation with human feces-or liver-derived HEV. Feces and bile of infected mice contained moderate to large amounts of HEV RNA, while HEV viremia was low and inconsistently detected. Mouse-passaged HEV could subsequently be propagated for up to 100 days in vitro. In contrast, cell culture-derived or seronegative EDTA-plasma-derived HEV was not infectious in inoculated animals. In conclusion, the infectivity of feces-derived human HEV is higher than that of EDTA-plasma-derived HEV both in vitro and in vivo. Persistent HEV gt3 infections in chimeric mice show preferential viral shedding toward mouse bile and feces, paralleling the course of infection in humans. H epatitis E virus (HEV) is a nonenveloped positive-sense single-stranded RNA virus of the genus Orthohepevirus and family Hepeviridae (1). Four major HEV genotypes infecting humans have been described so far. Genotype 1 (gt1) and gt2 strains are isolated only from humans, whereas gt3 and gt4 strains are considered zoonotic viruses, present in both humans and several other species like pigs and wild game. HEV is spread through the oral-fecal route via contaminated water in developing countries or, among other routes, via direct contact with animals or the consumption of undercooked meat in industrialized countries. In immunocompetent individuals, HEV infection is mainly self-limiting and often asymptomatic and thus remains largely underdiagnosed. HEV infections in immunosuppressed patients, such as solid-organ transplant recipients, often persist and can progress quickly to liver fibrosis and cirrhosis (2-4).HEV gt3 infections are emerging in Western countries, including France, the United Kingdom, and the Netherlands (5-7). Despite an overall decrease in anti-HEV seroprevalence from 1996 to 2011, young adult blood donors demonstrated higher seroprevalences from 2000 to 2011 (8, 9). In addition, HEV RNA-positive blood donations were reported to increase in the Netherlands since 2012 (10). Although the exact source of this HEV gt3 infection is unknown,...

Genotype 5 Hepatitis E Virus Produced by a Reverse Genetics System Has the Potential for Zoonotic Infection

“…(33) Because sofosbuvir inhibits G3 HEV replication in vitro and has shown antiviral activity in a patient with hepatitis E, it was recently reported as a candidate anti-HEV drug. (34,35) However, other reports have suggested that the inhibition of HEV replication by sofosbuvir is limited. (36,37) In our present experiments, a high concentration of PSI-7977 had only a limiting inhibitory effect against the virus replication, suggesting that sofosbuvir is not likely to be useful for the treatment of hepatitis E caused by G5 HEV infection.…”

Review article: hepatitis E—a concise review of virology, epidemiology, clinical presentation and therapy

“…[31][32][33] Interestingly, these reports indicated greater success using genotype 1 strains as inoculants (in contrast to in vitro studies) and all achieved greater infection and viraemia rates in inoculated mice using faecally derived HEV virions, in comparison to serum or culture derived. Two studies examined the use of ribavirin in inoculated chimeric mice and demonstrated the treatment to be successful in reducing viraemia in therapeutics.…”

Zoonotic Hepatitis E Virus: Classification, Animal Reservoirs and Transmission Routes

“…Moreover, the co-housing of an HEV-infected mouse with three naïve humanized mice led to successful HEV infection, demonstrating that HEV infection can be transmitted through the faecal oral route in humanized mice, direct physical contact or micro-injuries [115]. HEV-inoculated human liver chimeric mice were also shown to develop chronic HEV infection [116,117] and the treatment of HEV-infected humanised mice with ribavirin led to a statistically significant decrease in the level of HEV RNA in the serum and the faeces and in no more liver damage [115,116]. The human liver chimeric mouse model seems then to be a valuable tool to study the biology of chronic HEV infection and evaluate preclinical drugs.…”