Z Gastroenterol 2020; 58(01): e62
DOI: 10.1055/s-0039-3402272
Poster Visit Session V Viral Hepatitis and Immunology: Saturday, February 15, 2020, 11:00 am – 11:45 am, Lecture Hall P1
Georg Thieme Verlag KG Stuttgart · New York

In-vitro Activation and anti-viral Function of Innate NK cells in HEV Infection

A Adenugba
1   University Hospital Regensburg, Dept. of Surgery, Regensburg, Germany
,
P Kupke
1   University Hospital Regensburg, Dept. of Surgery, Regensburg, Germany
,
M Schemmerer
2   University Hospital Regensburg, Department of Microbiology and Virology, Regensburg, Germany
,
M Hornung
1   University Hospital Regensburg, Dept. of Surgery, Regensburg, Germany
,
H Schlitt
1   University Hospital Regensburg, Dept. of Surgery, Regensburg, Germany
,
E Geissler
1   University Hospital Regensburg, Dept. of Surgery, Regensburg, Germany
,
J Wenzel
2   University Hospital Regensburg, Department of Microbiology and Virology, Regensburg, Germany
,
J Werner
1   University Hospital Regensburg, Dept. of Surgery, Regensburg, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
03 January 2020 (online)

Also available at
 
 

    Background:

    Hepatitis E virus (HEV) infection is a leading cause of acute hepatitis worldwide. While progressing asymptomatically and self-limiting in most patients, HEV infection can lead to severe courses especially in immunocompromised patients such as organ transplant recipients.Although humoral immunity against HEV have been extensively investigated, very few studies have evaluated the role of host cellular immune responses during acute and chronic HEV infection. Understanding the role that cellular immunity plays in clearing primary HEV infection may help to explain the limited durability of immune responses against HEV. Here we asked whether innate immune responses from natural killer (NK) cells contribute to antiviral immunity.

    Methods:

    Human hepatoma cell lines PLC/PRF/5 and Huh-7 were inoculated with a full-length HEV virus (MOI 0.5) and cultured for 7 days. HEV-infected cells were then co-cultured with PBMC"s from healthy donors for 24h at an E:T ratio of 1:1. Viral replication was measured by real-time PCR and NK cells activation and function were analyzed by flow cytometry.

    Results:

    Co-culturing PBMCs with HEV-infected cells significantly decreased viral replication (PLC/PRF/5: 1.02e+07 vs. 8.99e+06; P = 0.0256; HuH-7: 1.74e+08 vs. 7,85e+07; P < 0.0001) and depleting NK cells from PBMCs diminished this anti-viral effect.

    As assessed by flow cytometry, NK cells produced significantly more anti-viral cytokines such as interferon (IFN)-γ (PLC/PRF/5: 10.04% vs. 8.54%; P = 0.0304; HuH-7: 16.29% vs. 10.84%; P < 0.0001) and tumor necrosis factor (TNF)-α (PLC/PRF/5: 27.69% vs. 23.67%; P = 0.0120; HuH-7: 5.26% vs. 3.88%; P < 0.0001) in response to HEV infection.

    However, co-culturing MAC-isolated NK cells with HEV-infected hepatoma cells showed neither a decrease in viral replication nor an activation and IFNγ-response of NK cells. Further isolation and depletion experiments revealed that NK cells need help by CD14+monocytes in order to execute their anti-viral function against HEV.

    Conclusions:

    NK cells in the context of PBMC"s decrease HEV replication through IFNγ-secretion. However, NK cells need the presence of CD14 monocytes in order to execute their anti-viral function.


    #