Ferritin protect shrimp Litopenaeus vannamei from WSSV infection by inhibiting virus replication.

Iron is considered as an essential element for all living organisms. Therefore, limiting iron availability may be key part of the host's innate immune response to various pathogens. Ferritin is a major iron storage protein in living cells and plays an important role in iron homeostasis. One way the host can transiently reduce iron bioavailability is by ferritin over expression. In invertebrates, ferritin was found to be up-regulated after pathogens challenge and is considered to be an important element in the innate immune system. This study was designed to investigate the involvement of ferritin in shrimp Litopenaeus vannamei defense against WSSV. We discovered that the viral load of shrimp injected with recombinant ferritin protein was lower than that of control group. The suppression of ferritin by dsRNA increased susceptibility to WSSV with 3-fold high viral copies. The present study documented that ferritin protected shrimp L. vannamei from WSSV by inhibiting virus replication. We presume that ferritin reduce iron availability, leading to inhibit the activity of ribonucleotide reductase and delay the replication of virus genome. This study provided new insights into the understanding of molecular responses and defense mechanisms in shrimp against WSSV.