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Viral Hepatitis
Chronic Hepatitis C Virus infection subverts vaccine induced T-cell immunity in humans
Christabel Kelly1,7,†, Leo Swadling1,†, Stefania Capone2, Anthony Brown1, Rachel Richardson1, John Halliday1,7, Annette von Delft1, Ye Oo3, David Mutimer3, Ayako Kurioka1, Felicity Hartnell1, Jane Collier7, Virginia Ammendola2, Mariarosaria Del Sorbo2, Fabiana Grazioli2, Maria Luisa Esposito2, Stefania Di Marco2, Loredana Siani2, Cinzia Traboni2, Adrian V.S. Hill1,8, Stefano Colloca2, Alfredo Nicosia2,4,5, Riccardo Cortese6, Antonella Folgori2, Paul Klenerman1,7,8 andEleanor Barnes1,7,8,*
DOI: 10.1002/hep.28294
© 2015 by the American Association for the Study of Liver Diseases
Issue
Cover image for Vol. 62 Issue 5
Hepatology
Accepted Article (Accepted, unedited articles published online and citable. The final edited and typeset version of record will appear in future.)
Article has an altmetric score of 2
1 Nuffield Department of Medicine, University of Oxford, Oxford, UK
2 ReiThera Srl (former Okairos Srl), Rome, Italy
3 Department of Hepatology, Queen Elizabeth Hospital, Birmingham, UK
4 CEINGE, via Gaetano Salvatore 486, Naples, Italy
5 Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
6 Keires AG, Basel, Switzerland
7 Oxford NIHR BRC, and Translational Gastroenterology Unit, Oxford, UK
8 The Jenner Institute, University of Oxford, Oxford, UK
† equal contribution
*Corresponding author: Prof. Eleanor Barnes, Peter Medawar Building, South Parks Rd, Oxford, UK, OX1 3SY
Keywords:
vaccination;adenovirus;immunotherapy;HCV;T cells
Abstract
Adenoviral vectors encoding hepatitis C virus (HCV) non-structural proteins induce multi-specific, high-magnitude, durable CD4+ and CD8+ T-cell responses in healthy volunteers. We now assess the capacity of these vaccines to induce functional HCV-specific immune responses and determine T-cell cross-reactivity to endogenous virus in patients with chronic HCV infection. HCV genotype-1 infected patients were vaccinated using heterologous adenoviral vectors (ChAd3-NSmut and Ad6-NSmut) encoding HCV non-structural proteins in a dose-escalation, prime-boost regimen, with and without concomitant pegylated interferon-α/ribavirin therapy. Analysis of immune responses ex vivo used human leukocyte antigen class-I pentamers, intracellular cytokine staining and fine mapping in interferon-γ ELISpot assays. Cross reactivity of T-cells with population and endogenous viral variants was determined following viral sequence analysis. Compared to healthy volunteers, the magnitude of HCV specific T-cell responses following vaccination was markedly reduced. CD8+ HCV specific T-cell responses were detected in 15/24 patients at the highest dose, whereas CD4+ T-cell responses were rarely detectable. Analysis of the host circulating viral sequence showed that T-cell responses were rarely elicited when there was sequence homology between vaccine immunogen and endogenous virus. In contrast, T-cells were induced in the context of genetic mismatch between vaccine immunogen and endogenous virus; however, these commonly failed to recognise circulating epitope variants and had a distinct partially-functional phenotype. Vaccination was well tolerated but had no significant effect on HCV viral load.
Conclusion: Vaccination with potent HCV adenoviral vectored vaccines fails to restore T-cell immunity except where there is genetic mismatch between vaccine immunogen and endogenous virus. This highlights the major challenge of overcoming T-cell exhaustion in the context of persistent antigen exposure with implications for cancer and other persistent infections. This article is protected by copyright. All rights reserved.
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