Fetal Calf Serum Exerts an Inhibitory Effect on Replication of Duck Hepatitis A Virus Genotype 1 in Duck Embryo Fibroblast Cells

Among the causative agents of duck viral hepatitis, duck hepatitis A virus genotype 1 (DHAV-1) is the most common virus reported in most outbreaks worldwide. How to propagate DHAV-1 in cell cultures efficiently remains a problem to be explored. Here, we aimed to test the effect of serum type on DHAV-1 replication in duck embryo fibroblast (DEF) cells. Comparative studies involved virus culture and passage, observation of cytopathic effect (CPE), virus quantification, and plaque formation assay. From the results of these investigations, we conclude that use of chicken serum (CS) in maintenance medium allows DHAV-1 to establish productive, cytocidal infection in DEF cells, whereas FCS exerts inhibitory effects on DHAV-1 replication, CPE development, and plaque formation. By using a neutralization test, we found that the direct action of FCS on virions is likely to play a key role in inhibiting DHAV-1 replication in DEF cells. Mechanism analyses revealed that FCS inhibits DHAV-1 replication at virus adsorption and reduces extracellular virus yields. The present work may shed light on a new perspective for antiviral agent development, and have provided a virus–host cell system for further studies on molecular mechanism involved DHAV-1 replication and pathogenesis.