Bertram Bengsch1, Bianca Martin1, Robert Thimme2. 1. Department of Medicine II, University Hospital of Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Germany; Faculty of Biology, University of Freiburg, Germany. 2. Department of Medicine II, University Hospital of Freiburg, Germany. Electronic address: Robert.Thimme@uniklinik-freiburg.de.
Abstract
BACKGROUND & AIMS: The upregulation of several inhibitory signalling pathways by exhausted HBV-specific CD8+ T cells in chronic infection is thought to contribute to viral persistence. Blockade of inhibitory receptors to reinvigorate exhausted T cell function is a promising novel therapeutic approach. However, little information is available regarding the relative contribution of individual inhibitory pathways to HBV-specific CD8+ T cell failure and the impact of inhibitory receptor blockade on restoration of T cell function in chronic HBV. METHODS: 98 HLA-A2+ chronically infected patients were analysed ex vivo for HBV-specific CD8+ T cell responses, the expression of multiple inhibitory receptors and T cell differentiation markers. The effects of inhibitory receptor blockade targeting PD-1, 2B4, Tim-3, CTLA-4, and BTLA were assessed in vitro. RESULTS: In our cohort, ex vivo HBV-specific CD8+ T cell responses were identified preferentially in HBeAg patients with low ALT and low viral load (inactive carriers). We observed a clear hierarchy of inhibitory receptor expression dominated by PD-1. The response to inhibitory receptor blockade was heterogeneous. Compared to the blockade of other inhibitory receptors, blockade of the PD-1 pathway resulted in the strongest increase in function. Of note, a positive effect of PD-1 blockade was linked to intermediate T cell differentiation. CONCLUSIONS: Despite the expression of multiple inhibitory receptors by HBV-specific CD8+ T cells, expression and response to blockade was dominated by PD-1. However, PD-1 expression did not predict response to blockade. Rather, response to blockade was associated with intermediate T cell differentiation. These findings have important implications for our understanding of inhibitory receptor blockade as a novel therapeutic strategy.
BACKGROUND & AIMS: The upregulation of several inhibitory signalling pathways by exhausted HBV-specific CD8+ T cells in chronic infection is thought to contribute to viral persistence. Blockade of inhibitory receptors to reinvigorate exhausted T cell function is a promising novel therapeutic approach. However, little information is available regarding the relative contribution of individual inhibitory pathways to HBV-specific CD8+ T cell failure and the impact of inhibitory receptor blockade on restoration of T cell function in chronic HBV. METHODS: 98 HLA-A2+ chronically infected patients were analysed ex vivo for HBV-specific CD8+ T cell responses, the expression of multiple inhibitory receptors and T cell differentiation markers. The effects of inhibitory receptor blockade targeting PD-1, 2B4, Tim-3, CTLA-4, and BTLA were assessed in vitro. RESULTS: In our cohort, ex vivo HBV-specific CD8+ T cell responses were identified preferentially in HBeAg patients with low ALT and low viral load (inactive carriers). We observed a clear hierarchy of inhibitory receptor expression dominated by PD-1. The response to inhibitory receptor blockade was heterogeneous. Compared to the blockade of other inhibitory receptors, blockade of the PD-1 pathway resulted in the strongest increase in function. Of note, a positive effect of PD-1 blockade was linked to intermediate T cell differentiation. CONCLUSIONS: Despite the expression of multiple inhibitory receptors by HBV-specific CD8+ T cells, expression and response to blockade was dominated by PD-1. However, PD-1 expression did not predict response to blockade. Rather, response to blockade was associated with intermediate T cell differentiation. These findings have important implications for our understanding of inhibitory receptor blockade as a novel therapeutic strategy.
Authors: T Jake Liang; Timothy M Block; Brian J McMahon; Marc G Ghany; Stephan Urban; Ju-Tao Guo; Stephen Locarnini; Fabien Zoulim; Kyong-Mi Chang; Anna S Lok Journal: Hepatology Date: 2015-10-27 Impact factor: 17.425
Authors: Wen Xiao; Long Feng Jiang; Xiao Zhao Deng; Dan Yan Zhu; Jia Ping Pei; Mao Lei Xu; Bing Jun Li; Chang Jun Wang; Jing Hai Zhang; Qi Zhang; Zhen Xian Zhou; Wei Liang Ding; Xiao Dong Xu; Ming Yue Journal: Immunol Res Date: 2016-04 Impact factor: 2.829