Hepatitis B Virus Inhibits Neutrophil Extracellular Traps Release by Modulating Reactive Oxygen Species Production and Autophagy

Neutrophils, an important component of the innate immune system, release extracellular traps (NETs) to eliminate invaded pathogens by trapping and killing microbes. A dysfunctional innate immune response is a major cause of persistent hepatitis B virus (HBV) infection. HBV has been shown to reduce neutrophil responses. The objectives of the present study were to determine whether HBV influenced NETs release and to identify the underlying mechanisms. Primary neutrophils and circulating blood samples were collected from 40 patients with a chronic hepatitis B infection (CHB) and 40 healthy controls to detect NETs release using a Quant-iT Pico Green dsDNA assay and to determine the levels of HBV-DNA and HBV markers. NETs release was decreased in patients with a CHB infection, and hepatitis B surface antigen, hepatitis B e antigen and hepatitis B core antibody levels negatively correlated with NETs release. The Quant-iT Pico Green dsDNA assay and western blotting were used to examine the effect of HBV proteins (HBV X protein, HBV C protein, HBV E protein and HBV S protein) on NETs release in vitro. Based on the flow cytometry and western blot data, HBV C protein and HBV E protein inhibited NETs release by decreasing reactive oxygen species (ROS) production and autophagy. Overall, HBV may inhibit NETs release by modulating ROS production and autophagy to escape the immune system and promote the establishment of a chronic infection.