Hepatitis E Virus (HEV) is an important cause of acute hepatitis in adults in developing countries. In the Indian subcontinent, the virulent genotype-1 strain was isolated from symptomatic, fulminant AVH cases. The high mortality rate of pregnant women with hepatitis E infection and lack of a vaccine against HEV underscores the need for additional basic research. Robust tissue culture systems to propagate HEV genotype-1 are known to be the main stay for better understanding of virus-host interactions, and help design genotype specific antiviral agents and evaluate antiviral efficacy. The inability to propagate HEV can be eliminated by several different approaches and we are exploring novel strategies to find one robust tissue culture system to propagate infectious HEV Gt-1 clones.
Achievements: The ability to induce random mutations, along with a degree of control over the mutations introduced in the FL genomes of RNA viruses has been explored as a model molecular system for investigating mutant clouds in cultured cells. In this work, we developed a simple, convenient and rapid system called Full Length – Mutant RNA Cloud (FL-MRC), for synthesizing HEV mutant clouds, which were then transfected in hepatoma cells as an inoculum to study phenotypic behavior of the clouds. One of the important outcome of this project is that mutant clouds of HEV are not equally adaptive; rather their behavior differs depending on cloud size and composition as shown in immunofluorescence assay for ORF1 and dsRNA. This observation can be attributed to the differential abilities of different mutant clouds in overcoming the threshold of selection pressures or bottlenecks posed by host-virus interactions during infection (Agarwal et al., J Virol. 2018).