Hepatitis B Virus Particles Activate Toll‐Like Receptor 2 Signaling Initially Upon Infection of Primary Human Hepatocytes
Authors: Hideo A Baba
Melanie Werner
Ruth Broering
Heiner Wedemeyer
Andreas Paul
Guido Gerken
Thekla Kemper
Joerg F Schlaak
Juergen Treckmann
Yvonne Ladiges
Maura Dandri
Zhenhua Zhang
Catherine I Real
Mengji Lu
Lena Allweiss
Martin Trippler
Stefan Schefczyk
Xufeng Luo
Olympia E Anastasiou
Journal: Hepatology (2020)
Discipline: CLINICAL MEDICINE
Keywords: hepatitis B virus; innate immune responses; primary human hepatocytes; NFκB; inflammatory cytokines
Affiliations: Department of Gastroenterology and Hepatology, University Hospital Essen, University Duisburg-Essen, Essen, Germany., Institute of Virology, University Hospital Essen, University Duisburg-Essen, Essen, Germany., Department of Medicine, Center for Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany., Department of General, Visceral and Transplantation Surgery, University Hospital Essen, University of Duisburg-Essen, Essen, Germany., Department of Pathology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany., Department of Internal medicine, Evangelisches Klinikum Niederrhein GmbH, Duisburg, Germany.

Abstract:  Background and aims: To date, conflicting data exist as to whether hepatitis B virus (HBV) has the ability to induce innate immune responses. Here, we investigated cellular changes after the first contact between HBV and primary human hepatocytes (PHH) in vitro and in vivo. Approach and results: The exposure of PHH to HBV particles resulted in nuclear translocation of NFκB, followed by the expression and secretion of inflammatory cytokines (IL [interleukin] 1B, IL6, and TNF [tumor necrosis factor]). Ultraviolet irradiation of viral particles suppressed HBV infectivity but not the induction of cytokines in PHH, suggesting that the inoculum contains the immune-inducing agent. Purified HBV particles on the whole, which were prepared from HBV DNA-positive and protein-rich fractions after heparin column separation, still had immune-inducing capacity in PHH. The HBV-induced gene expression profile was similar to that induced by toll-like receptor 2 (TLR2) ligand Pam3Cys, but different from those induced by the viral sensors TLR3 or TLR7-9. Treatment of PHH with both HBV particles and Pam3Cys led to phosphorylation of ERK (extracellular signal-regulated kinase), JNK, and p38 mitogen-activated protein kinases as well as NFκB (nuclear factor kappa B). Finally, HBV-induced gene expression could be neutralized by TLR2-specific antibodies. Of note, pretreatment with an HBV entry inhibitor attenuated the TLR2-mediated response to HBV, suggesting a receptor binding-related mechanism. In liver-humanized uPA/severe combined immunodeficient (SCID)/beige mice challenged with HBV in vivo, immune induction could only marginally be seen. Conclusions: PHHs are able to sense HBV particles through TLR2, leading to an activation of anti-HBV immune responses in vitro. These findings challenge the previously described stealth properties of HBV. 

Retracted: No

PubPeer comments:
 In figure 3(D), ERK and Aktin are obviously the same blot. It was stated that Westernblot was performed as previously described (DOI: 10.1111 jvh.12174), but the pattern seemed far from similar. ![file] , 
 There appears to be some image duplications and unexpected similarities in figure 3D. ![file] ,