Pregnancy serum facilitates hepatitis E virus replication in vitro.

Hepatitis E virus (HEV) infection causes high mortality in pregnant women. However, the pathogenic mechanisms of HEV infection in pregnant women remain unknown. In this study, the roles of pregnancy serum in HEV infection were investigated using an efficient cell culture system. HEV infection was exacerbated by supplementing with pregnancy serum, especially theat in third trimester of pregnancy. Oestrogen receptors (ER-α and ER-β) were activated in cells supplemented with pregnancy serum and were significantly inhibited during HEV infection. Type I IFN, especially IFN-β, showed delayed upregulation in HEV-infected cells supplemented with the serum in the third trimester of pregnancy, which indicated that delayed IFN-β expression may facilitate viral replication. Results suggested that pregnancy serum accelerated HEV replication by suppressing oestrogen receptors and type I IFN in the early stage of infection.