Hepatitis D infection induces IFN-β-mediated NK cell activation and TRAIL-dependent cytotoxicity

Front Immunol. 2023 Dec 8:14:1287367. doi: 10.3389/fimmu.2023.1287367. eCollection 2023.

Abstract

Background and aims: The co-infection of hepatitis B (HBV) patients with the hepatitis D virus (HDV) causes the most severe form of viral hepatitis and thus drastically worsens the course of the disease. Therapy options for HBV/HDV patients are still limited. Here, we investigated the potential of natural killer (NK) cells that are crucial drivers of the innate immune response against viruses to target HDV-infected hepatocytes.

Methods: We established in vitro co-culture models using HDV-infected hepatoma cell lines and human peripheral blood NK cells. We determined NK cell activation by flow cytometry, transcriptome analysis, bead-based cytokine immunoassays, and NK cell-mediated effects on T cells by flow cytometry. We validated the mechanisms using CRISPR/Cas9-mediated gene deletions. Moreover, we assessed the frequencies and phenotype of NK cells in peripheral blood of HBV and HDV superinfected patients.

Results: Upon co-culture with HDV-infected hepatic cell lines, NK cells upregulated activation markers, interferon-stimulated genes (ISGs) including the death receptor ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), produced interferon (IFN)-γ and eliminated HDV-infected cells via the TRAIL-TRAIL-R2 axis. We identified IFN-β released by HDV-infected cells as an important enhancer of NK cell activity. In line with our in vitro data, we observed activation of peripheral blood NK cells from HBV/HDV co-infected, but not HBV mono-infected patients.

Conclusion: Our data demonstrate NK cell activation in HDV infection and their potential to eliminate HDV-infected hepatoma cells via the TRAIL/TRAIL-R2 axis which implies a high relevance of NK cells for the design of novel anti-viral therapies.

Keywords: HBV; HDV; IFN-beta; NK cells; TRAIL.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Carcinoma, Hepatocellular* / metabolism
  • Hepatitis D* / metabolism
  • Hepatitis Delta Virus / genetics
  • Humans
  • Interferons / metabolism
  • Killer Cells, Natural
  • Ligands
  • Liver Neoplasms* / metabolism
  • Tumor Necrosis Factors / metabolism

Substances

  • Ligands
  • Interferons
  • Tumor Necrosis Factors

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The project was supported by grants from the German Research Foundation: TRR179 (TP02 to CN-H, Z03 to KR, TP07 to AC and TP016 to SU), SFB1366 (319 394046768-SFB 1366; C02 to AC), SPP1937 (CE 140/2-2 to AC), SFB-TRR156 (B10N to AC), RTG2099 (321259332240 - RTG2099; P9 to AC), RTG2727 (445549683; B1.2 to AC), by the German Center for Infectious Diseases (DZIF) TTU Hepatitis (5.807 and 5.704 to SU), by a network grant of the European Commission (H2020-MSCA-MC322; ITN-765104-MATURE-NK to AC), by the framework of the excellence strategy of the federal and state governments of Germany and by the Angioformatics platform of the European Center for Angioscience (ECAS). The funding sources had no involvement in study design, in the collection, analysis and interpretation of data, in the writing of the report, and in the decision to submit the article for publication.