Hepatitis E Virus Genotype 1 Infection of Swine Kidney Cells In Vitro Is Inhibited at Multiple Levels

Genotype 1 hepatitis E viruses (HEVs) are restricted to primate hosts, whereas genotype 3 HEVs predominantly infect swine, in addition to primates. In order to identify possible determinants of the host range, infectious recombinant viruses and chimeras of a genotype 1 isolate and a genotype 3 isolate were compared for their ability to infect versus transfect cultured human HepG2/C3A cells and swine LLC-PK cells. The patterns of luciferase expression from virus replicons containing the Gaussia luciferase gene in place of the viral ORF2 or ORF3 genes demonstrated that translation of the ORF2 capsid gene of genotype 1 virus is severely inhibited in swine kidney cells compared to its translation in rhesus macaque kidney or human liver cells. Therefore, this virus may produce insufficient capsid protein for optimal assembly in swine cells. Infectivity assays with a virus containing a chimeric capsid protein confirmed that amino acids 456 to 605 of the virus capsid protein comprised the virus receptor-binding region and suggested that genotype 1 viruses may be prevented from infecting swine because genotype 1 viruses are unable to enter swine cells. Rhesus macaque cells appeared to be better than human cells for growing the genotype 1 virus. These cell and virus combinations may serve as a useful in vitro model with which to study determinants of the natural host range of this virus.