ABSTRACT
CD8(+) T cells are the main effector lymphocytes in the control of hepatitis B virus (HBV) infection. However, limitations of model systems, such as low infection rates, restrict mechanistic studies of HBV-specific CD8(+) T cells. Here, we established a novel immunological cell culture model based on HBV-infected HepG2(hNTCP) cells that endogenously processed viral antigens and presented them to HBV-specific CD8(+) T cells. This induced cytolytic and noncytolytic CD8(+) T-cell effector functions and reduction of viral loads.
Subject(s)
CD8-Positive T-Lymphocytes/immunology , Hepatitis B virus/growth & development , Hepatitis B virus/immunology , T-Lymphocytes, Cytotoxic/immunology , Cytological Techniques , Hep G2 Cells , Humans , Models, TheoreticalABSTRACT
OBJECTIVE: Skewed T helper (TH) cell responses and specific functions of TH1, TH2, TH17, and Treg cells have been implicated in the pathogenesis of inflammatory bowel disease (IBD) that led to the establishment of the pathogenic TH1/TH2 and TH17/Treg cell imbalance paradigms. However, the relevant TH cell population driving mucosal inflammation is still unknown. METHODS: We performed a comprehensive TH cell profiling of circulating and intestinal lymphocytes isolated from patients with Crohn's disease (CD; n = 69) and ulcerative colitis (UC; n = 41) undergoing endoscopy or surgical resection and compared them with healthy controls (n = 45). Mucosal inflammation was assessed endoscopically and histologically. TH cells were analyzed by flow cytometric evaluation of cytokine production and differentiation marker expression. RESULTS: Specialized TH cell populations were enriched in the intestinal mucosa compared with peripheral blood. Specifically, we observed a concomitant upregulation of TH17 cells and Tregs in active inflammatory lesions in patients with both CD and UC compared with quiescent/mildly inflamed lesions and healthy tissue. Of note, interferon γ+ interleukin (IL)-17+coproducing CD4+ T cells with high expression of T-bet, CD26, and IL-22 resembling recently described pathogenic TH17 cells were specifically enriched in the inflamed mucosal tissue. CONCLUSIONS: Our results argue against the controversial TH1/TH2 or TH17/Treg paradigms. In contrast, they suggest that a subpopulation of TH17 cells sharing a TH1 signature may be specifically involved in intestinal inflammation in CD and UC. These findings provide a better understanding of IBD pathogenesis and may help explain the efficacy of anti-IL-12p40/IL-23 and failure of anti-IL-17A therapies despite the enrichment of TH17 cells.
Subject(s)
CD4-Positive T-Lymphocytes/immunology , Inflammation/immunology , Inflammatory Bowel Diseases/immunology , Interferon-gamma/metabolism , Interleukin-17/metabolism , Intestinal Mucosa/immunology , T-Lymphocytes, Helper-Inducer/immunology , CD4-Positive T-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/pathology , Case-Control Studies , Cell Differentiation , Flow Cytometry , Humans , Inflammation/metabolism , Inflammation/pathology , Inflammatory Bowel Diseases/metabolism , Inflammatory Bowel Diseases/pathology , Intestinal Mucosa/metabolism , Intestinal Mucosa/pathology , Severity of Illness Index , T-Lymphocytes, Helper-Inducer/metabolism , T-Lymphocytes, Helper-Inducer/pathology , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , T-Lymphocytes, Regulatory/pathologyABSTRACT
BACKGROUND & AIMS: Chronic hepatitis C virus (HCV) infection is characterised by a failure of virus-specific CD8+ T cells that is mainly caused by viral escape and T cell exhaustion. Constant antigen stimulation has been suggested to contribute to HCV-specific CD8+ T cell exhaustion. However, IFN-based therapies failed to recover HCV-specific CD8+ T cell function suggesting that the damage to CD8+ T cells may be permanent even after antigen removal. It was therefore the objective of this study to analyse the impact of inhibition of ongoing viral replication by IFN-free therapy with direct acting antivirals (DAA) on the phenotype and function of HCV-specific CD8+ T cells. METHODS: Virus-specific CD8+ T cells obtained from a patient cohort of 51 previously untreated chronically infected patients undergoing IFN-free therapy with a combination of faldaprevir (a protease inhibitor) and deleobuvir (a non-nucleoside polymerase inhibitor) with or without ribavirin were analysed ex vivo and after in vitro expansion at baseline, wk4, wk 12, and after treatment. RESULTS: Our results show the rapid restoration of proliferative HCV-specific CD8+ T cells in the majority of patients with SVR12 within 4 weeks of therapy suggesting that IFN-free therapy mediated antigen removal may restore CD8+ T cell function. CONCLUSIONS: This study indicates a specific restoration of proliferative HCV-specific CD8+ T cells under IFN-free therapy. This is in contrast to PegIFN-based therapies that have been shown not to restore T cell function during and after chronic infection.
