Follicular T helper cells shape the HCV-specific CD4+ T cell repertoire after virus elimination
Maike Smits, … , Robert Thimme, Tobias Boettler
Maike Smits, … , Robert Thimme, Tobias Boettler
Published November 7, 2019
Citation Information: J Clin Invest. 2020;130(2):998-1009. https://doi.org/10.1172/JCI129642.
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Clinical Medicine Immunology Infectious disease

Follicular T helper cells shape the HCV-specific CD4+ T cell repertoire after virus elimination

Abstract

BACKGROUND Chronic hepatitis C virus (HCV) infection is characterized by a severe impairment of HCV-specific CD4+ T cell help that is driven by chronic antigen stimulation. We aimed to study the fate of HCV-specific CD4+ T cells after virus elimination.METHODS HCV-specific CD4+ T cell responses were longitudinally analyzed using MHC class II tetramer technology, multicolor flow cytometry, and RNA sequencing in a cohort of patients chronically infected with HCV undergoing therapy with direct-acting antivirals. In addition, HCV-specific neutralizing antibodies and CXCL13 levels were analyzed.RESULTS We observed that the frequency of HCV-specific CD4+ T cells increased within 2 weeks after initiating direct-acting antiviral therapy. Multicolor flow cytometry revealed a downregulation of exhaustion and activation markers and an upregulation of memory-associated markers. Although cells with a Th1 phenotype were the predominant subset at baseline, cells with phenotypic and transcriptional characteristics of follicular T helper cells increasingly shaped the circulating HCV-specific CD4+ T cell repertoire, suggesting antigen-independent survival of this subset. These changes were accompanied by a decline of HCV-specific neutralizing antibodies and the germinal center activity.CONCLUSION We identified a population of HCV-specific CD4+ T cells with a follicular T helper cell signature that is maintained after therapy-induced elimination of persistent infection and may constitute an important target population for vaccination efforts to prevent reinfection and immunotherapeutic approaches for persistent viral infections.FUNDING Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), the National Institute of Allergy and Infectious Diseases (NIAID), the European Union, the Berta-Ottenstein-Programme for Advanced Clinician Scientists, and the ANRS.

Authors

Maike Smits, Katharina Zoldan, Naveed Ishaque, Zuguang Gu, Katharina Jechow, Dominik Wieland, Christian Conrad, Roland Eils, Catherine Fauvelle, Thomas F. Baumert, Florian Emmerich, Bertram Bengsch, Christoph Neumann-Haefelin, Maike Hofmann, Robert Thimme, Tobias Boettler

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Figure 2

Frequency of HCV-specific CD4+ T cells increases shortly after initiation of DAA therapy.

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Frequency of HCV-specific CD4+ T cells increases shortly after initiatio...
(A and B) PBMCs from patients positive for HLA-DRB1*01:01 or HLA-DRB1*15:01, chronically infected with HCV undergoing DAA therapy were acquired before antiviral therapy (baseline), at W2 after initiation of therapy, at EOT, and at follow-up (24 weeks after EOT). Bead-based tetramer enrichment and surface staining were performed as described in the Methods section prior to analysis by flow cytometry. (A) Frequencies of HCV-specific CD4+ T cells within CD4+ T cells are shown as percentage and (B) as fold change compared with baseline frequencies (n = 29). (C) Representative pseudocolor flow cytometry plots with the corresponding frequency are shown for 2 patients (P3 and P15). (D) Frequencies of HCV-specific CD4+ T cells at baseline were subtracted from the frequencies at W2 to visualize the decrease or increase in the frequency. All patients analyzed at both time points are included in the analysis (n = 40). Dots represent the frequency at baseline and bars represent the calculated decrease or increase in the frequency (W2 – baseline). Each symbol represents 1 patient, bars represent medians (A and B). ****P < 0.0001, nonparametric distribution with Wilcoxon’s matched-pairs signed-rank test was applied between indicated groups. Due to multiple comparisons (n = 3), significance level was adjusted using Bonferroni’s correction and P values of < 0.01 were considered statistically significant. Thus, P values > 0.01 are not indicated.