According to Hepatitis C Virus (HCV) Infection Stage, Interleukin-7 Plus 4-1BB Triggering Alone or Combined with PD-1 Blockade Increases TRAF1 ^low HCV-Specific CD8 ⁺ Cell Reactivity

2区 · 医学

Article

作者: Madejón, Antonio ; Larrubia, Juan-Ramón ; Sanz-de-Villalobos, Eduardo ; Parra-Cid, Trinidad ; García-Samaniego, Javier ; Moreno-Cubero, Elia ; Subirá, Dolores ; González-Praetorius, Alejandro ; Miquel, Joaquín ; Olveira, Antonio

ABSTRACT Hepatitis C virus (HCV)-specific CD8 + T cells suffer a progressive exhaustion during persistent infection (PI) with HCV. This process could involve the positive immune checkpoint 4-1BB/4-1BBL through the loss of its signal transducer, TRAF1. To address this issue, peripheral HCV-specific CD8 + T cells (pentamer-positive [pentamer + ]/CD8 + T cells) from patients with PI and resolved infection (RI) after treatment were studied. The duration of HCV infection and the liver fibrosis progression rate inversely correlated with the likelihood of detection of peripheral pentamer + /CD8 + cells. In PI, pentamer + /CD8 + cells had impaired antigen-specific reactivity that worsened when these cells were not detectable ex vivo . Short/midduration PI was characterized by detectable peripheral PD-1 + CD127 low TRAF1 low cells. After triggering of T cell receptors (TCR), the TRAF1 level positively correlated with the levels of CD127, Mcl-1, and CD107a expression and proliferation intensity but negatively with PD-1 expression, linking TRAF1 low to exhaustion. In vitro treatment with interleukin-7 (IL-7) upregulated TRAF1 expression, while treatment with transforming growth factor-β1 (TGF-β1) did the opposite, suggesting that the IL-7/TGF-β1 balance, besides TCR stimulation, could be involved in TRAF1 regulation. In fact, the serum TGF-β1 concentration was higher in patients with PI than in patients with RI, and it negatively correlated with TRAF1 expression. In line with IL-7 increasing the level of TRAF1 expression, IL-7 plus 4-1BBL treatment in vitro enhanced T cell reactivity in patients with short/midduration infection. However, in patients with long-lasting PI, anti-PD-L1, in addition to the combination of IL-7 and 4-1BBL, was necessary to reestablish T cell proliferation in individuals with slowly progressing liver fibrosis (slow fibrosers) but had no effect in rapid fibrosers. In conclusion, a peripheral hyporeactive TRAF1 low HCV-specific CD8 + T cell response, restorable by IL-7 plus 4-1BBL treatment, characterizes short/midduration PI. In long-lasting disease, HCV-specific CD8 + T cells are rarely detectable ex vivo , but treatment with IL-7, 4-1BBL, and anti-PD-L1 recovers their reactivity in vitro in slow fibrosers. IMPORTANCE Hepatitis C virus (HCV) infects 71 million people worldwide. Two-thirds develop a chronic disease that can lead to cirrhosis and hepatocellular carcinoma. Direct-acting antivirals clear the infection, but there are still patients who relapse. In these cases, additional immunotherapy could play a vital role. A successful anti-HCV immune response depends on virus-specific CD8 + T cells. During chronic infection, these cells are functionally impaired, which could be due to the failure of costimulation. This study describes exhausted specific T cells, characterized by low levels of expression of the signal transducer TRAF1 of the positive costimulatory pathway 4-1BB/4-1BBL. IL-7 upregulated TRAF1 expression and improved T cell reactivity in patients with short/midduration disease, while in patients with long-lasting infection, it was also necessary to block the negative PD-1/PD-L1 checkpoint. When the results are taken together, this work supports novel ways of restoring the specific CD8 + T cell response, shedding light on the importance of TRAF1 signaling. This could be a promising target for future immunotherapy.

2017-03-01·Cytometry Part B: Clinical Cytometry4区 · 医学

Streptamer technology allows accurate and specific detection of CMV‐specific HLA‐A*02 CD8⁺ T cells by flow cytometry

4区 · 医学

Article

作者: Ciáurriz, Miriam ; Ramírez, Natalia ; Bandrés, Eva ; Olavarría, Eduardo ; Pérez‐Valderrama, Estela ; Ibáñez, Berta ; Zabalza, Amaya ; Mansilla, Cristina ; Beloki, Lorea ; Lachén, Mercedes

BackgroundMultimer technology is widely used to screen antigen‐specific immune recovery after allogeneic hematopoietic stem cell transplantation (allo‐HSCT) as it enables identification, enumeration, phenotypic characterization and isolation of virus‐specific T‐cells. Novel approaches of multimerization might improve on classical tetramer staining; however, their use as standard monitoring technique to quantify antigen‐specific cells has not been validated yet. We have compared two of these available multimeric complexes: pentamer and streptamer to select the best strategy for the incorporation into clinical monitoring practice.MethodsCMVpp65495‐503‐specific HLA‐A*02:01 CD8+ T lymphocytes (CTLA*02:01‐CMVpp65495‐503) were examined with pentamer and streptamer in peripheral blood cells of 77 healthy volunteers. Quantitative and qualitative analyses were performed to compare the precision and repeatability, sensitivity and accuracy and specificity of both technologies by flow cytometry.ResultsStandard deviation for both techniques was less than 0.05 showing that they are repetitive and precise. Both techniques significantly correlated at high frequencies (rSpearman = 0.9422; P < 0.0001) but it was lost at lower levels (<1%) of CTLA*02:01‐CMVpp65495‐503 (rSpearman = 0.3351; P = 0.1376). Streptamer is more accurate for the detection of CTLA*02:01‐CMVpp65495‐503 providing significantly closer values to the theoretical ones (P < 0.0001) as pentamer binds unspecifically to a notable proportion of non‐CMV‐specific CD8+ T‐cells.ConclusionOur results suggest that streptamer multimer provides precise, accurate and specific results to detect CTLA*02:01‐CMVpp65495‐503 by flow cytometry. Streptamer multimer can be used not only for the monitoring of early CTLA*02:01‐CMVpp65495‐503 reconstitution in immunosuppressed patients following allo‐HSCT but also, in conjunction with its reversibility role, for the isolation of CTLA*02:01‐CMVpp65495‐503 for its future use in adoptive immunotherapy. © 2016 International Clinical Cytometry Society

2016-07-01·Journal of Molecular Graphics and Modelling4区 · 生物学

Multi-scale molecular dynamics study of cholera pentamer binding to a GM1-phospholipid membrane

4区 · 生物学

Article

作者: Sridhar, Akshay ; Dasmahapatra, Ashok Kumar ; Kumar, Amit

The AB5 type toxin produced by the Vibrio cholerae bacterium is the causative agent of the cholera disease. The cholera toxin (CT) has been shown to bind specifically to GM1 glycolipids on the membrane surface. This binding of CT to the membrane is the initial step in its endocytosis and has been postulated to cause significant disruption to the membrane structure. In this work, we have carried out a combination of coarse-grain and atomistic simulations to study the binding of CT to a membrane modelled as an asymmetrical GM1-DPPC bilayer. Simulation results indicate that the toxin binds to the membrane through only three of its five B subunits, in effect resulting in a tilted bound configuration. Additionally, the binding of the CT can increase the area per lipid of GM1 leaflet, which in turn can cause the membrane regions interacting with the bound subunits to experience significant bilayer thinning and lipid tail disorder across both the leaflets.

100 项与 RhUL128C-MVA 相关的药物交易

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