The early host innate immune response to duck hepatitis B virus infection

Abstract

The early phase after hepatitis B virus infection could play a crucial role in clearance and/or persistence of the virus, particularly in neonates. This work compared the early phase of duck hepatitis B virus infection in 1-day-old (D1) and 28-day-old (D28) ducks to determine whether differences in viral or host innate immune response can be related to the difference in outcome. In the first phase, almost immediately after inoculation, virus was taken up by components of the reticulo-endothelial systems, particularly liver-specific macrophages, Kupffer cells. Very early after infection, the induction of alpha interferon by infected hepatocytes occurred and was rapidly reinforced by recruitment of effector lymphocytes, which directly or indirectly caused apoptosis, eliminating infected hepatocytes, as was seen in mature birds. In addition, a lack of lymphocytic infiltration of the liver was found in D1 ducks, which supports the suggestion that the innate immune network is less effective in D1 ducks. Taken together, these results suggest that failure of the co-ordinated innate immune response rather than a defect in induced antiviral cell-mediated immunity may be the key factor which makes baby ducks vulnerable to persistence of hepadnavirus infection.

A High Level of Mutation Tolerance in the Multifunctional Sequence Encoding the RNA Encapsidation Signal of an Avian Hepatitis B Virus and Slow Evolution Rate Revealed by In Vivo Infection

“…5 and 6A). This suggests that a threshold replication rate of between 20% and 50% of that of wt DHBV is required to overcome in vivo host defenses that contain the spread of infection (28,57,65). Since we did not find direct evidence for a major impact of the mutations on any other function of the Dε sequence, save on expression of DHBeAg (see below), the single most important contribution by a given Dε sequence to reproductive success probably comes from its ability to provide a suitable RNA template for productive interaction with P protein.…”

Duck virus enteritis (duck plague) – a comprehensive update

“…Hence, the diagnostic assays based on serology are of not much significance, as well as are not useful in acute infection, serological surveillance and while measuring post-vaccination immune response (Toth 1972;Toth & Norcross 1981;Vickery et al 1999a, Vickery et al 1999a, 1999bTang et al 2001;Qi, Yang, Cheng, Wang, Zhu, et al 2009;Tohidi-Esfahani et al 2010;Yang et al 2010). Although cell-mediated immune response has been shown to play a more important role during DEV infection (Vickery et al 1999a(Vickery et al , 1999b, it is possible to detect the anti-DEV neutralizing antibodies (Saade et al 2008;Aravind et al 2012).…”

Liver macrophages: Friend or foe during hepatitis B infection?

“…Liver MΦ are equipped to recognize pathogens and mount an efficient pro‐inflammatory response if needed to prevent, control and delay infections that could become chronic, as described above. A study in Pekin duck revealed that minutes after inoculation, HBV was taken up by liver MΦ, highlighting their interaction in vivo . As a DNA virus with RNA intermediates, HBV could theoretically be recognized by several PRR expressed by liver MΦ such as TLR3 or RIGI/MDA5 as well as some cytosolic DNA sensors .…”