scholarly journals Protein Energy Malnutrition during Vaccination Has Limited Influence on Vaccine Efficacy but Abolishes Immunity if Administered during Mycobacterium tuberculosis Infection

2015 ◽  
Vol 83 (5) ◽  
pp. 2118-2126 ◽  
Author(s):  
Truc Hoang ◽  
Else Marie Agger ◽  
Joseph P. Cassidy ◽  
Jan P. Christensen ◽  
Peter Andersen
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
T Cell ◽  
Cd4 T Cells ◽  
Protein Energy Malnutrition ◽  
T Cell Subsets ◽  
Content Type ◽  
Protein Energy ◽  
Tnf Α ◽  
Ifn Γ

Protein energy malnutrition (PEM) increases susceptibility to infectious diseases, including tuberculosis (TB), but it is not clear how PEM influences vaccine-promoted immunity to TB. We demonstrate that PEM during low-level steady-state TB infection in a mouse model results in rapid relapse ofMycobacterium tuberculosis, as well as increased pathology, in bothMycobacterium bovisBCG-vaccinated and unvaccinated animals. PEM did not change the overall numbers of CD4 T cells in BCG-vaccinated animals but resulted in an almost complete loss of antigen-specific cytokine production. Furthermore, there was a change in cytokine expression characterized by a gradual loss of multifunctional antigen-specific CD4 T cells and an increased proportion of effector cells expressing gamma interferon and tumor necrosis factor alpha (IFN-γ+TNF-α+and IFN-γ+cells). PEM duringM. tuberculosisinfection completely blocked the protection afforded by the H56-CAF01 subunit vaccine, and this was associated with a very substantial loss of the interleukin-2-positive memory CD4 T cells promoted by this vaccine. Similarly, PEM during the vaccination phase markedly reduced the H56-CAF01 vaccine response, influencing all cytokine-producing CD4 T cell subsets, with the exception of CD4 T cells positive for TNF-α only. Importantly, this impairment was reversible and resupplementation of protein during infection rescued both the vaccine-promoted T cell response and the protective effect of the vaccine againstM. tuberculosisinfection.

scholarly journals Differentiation of Antigen-Specific T Cells with Limited Functional Capacity during Mycobacterium tuberculosis Infection

2013 ◽  
Vol 82 (1) ◽  
pp. 132-139 ◽  
Author(s):  
Yun Hee Jeong ◽  
Bo-Young Jeon ◽  
Sun-Hwa Gu ◽  
Sang-Nae Cho ◽  
Sung Jae Shin ◽  
...  
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
T Cell ◽  
Memory T Cells ◽  
Interleukin 2 ◽  
Effector Memory ◽  
Memory Cells ◽  
Content Type ◽  
Tnf Α ◽  
Ifn Γ

ABSTRACTDespite the generation ofMycobacterium tuberculosis-specific T cell immune responses during the course of infection, only 5 to 10% of exposed individuals develop active disease, while others develop a latent infection. This phenomenon suggests defectiveM. tuberculosis-specific immunity, which necessitates more careful characterization ofM. tuberculosis-specific T cell responses. Here, we longitudinally analyzed the phenotypes and functions ofM. tuberculosis-specific T cells. In contrast to the functional exhaustion of T cells observed after chronic infection,M. tuberculosis-specific CD8+T cells differentiated into either effector (CD127loCD62Llo) or effector memory (CD127hiCD62Llo) cells, but not central memory cells (CD127hiCD62Lhi), with low programmed death 1 (PD-1) expression, even in the presence of high levels of bacteria. Additionally,M. tuberculosis-specific CD8+and CD4+T cells produced substantial levels of tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ), but not interleukin 2 (IL-2), uponin vitrorestimulation. AmongM. tuberculosis-specific CD8+T cells, CD127hieffector memory cells displayed slower ongoing turnover but greater survival potential. In addition, these cells produced more IFN-γ and TNF-α and displayed lytic activity upon antigen stimulation. However, the effector function ofM. tuberculosis-specific CD8+CD127hieffector memory T cells was inferior to that of canonical CD8+CD127himemory T cells generated after acute lymphocytic choriomeningitis virus infection. Collectively, our data demonstrate thatM. tuberculosis-specific T cells can differentiate into memory T cells during the course ofM. tuberculosisinfection independent of the bacterial burden but with limited functionality. These results provide a framework for further understanding the mechanisms ofM. tuberculosisinfection that can be used to develop more effective vaccines.

scholarly journals T-Cell Cytokine Response in Salmonella Typhimurium-Vaccinated versus Infected Pigs

Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 845
Author(s):  
Selma Schmidt ◽  
Heinrich Kreutzmann ◽  
Maria Stadler ◽  
Kerstin H. Mair ◽  
Melissa R. Stas ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Salmonella Typhimurium ◽  
Cd4 T Cells ◽  
T Cell Subsets ◽  
Local Immunity ◽  
Effective Measure ◽  
Treatment Groups ◽  
Tnf Α ◽  
Ifn Γ

Vaccination with the live attenuated vaccine Salmoporc is an effective measure to control Salmonella Typhimurium (STM) in affected swine populations. However, the cellular immune response evoked by the Salmoporc vaccine including differences in vaccinated pigs versus non-vaccinated pigs upon STM infection have not been characterized yet. To investigate this, tissue-derived porcine lymphocytes from different treatment groups (vaccination-only, vaccination and infection, infection-only, untreated controls) were stimulated in vitro with heat-inactivated STM and abundances of IFN-γ, TNF-α and/or IL-17A-producing T-cell subsets were compared across organs and treatment groups. Overall, our results show the induction of a strong CD4+ T-cell response after STM infection, both locally and systemically. Low-level induction of STM-specific cytokine-producing CD4+ T cells, notably for the IFN-γ/TNF-α co-producing phenotype, was detected after vaccination-only. Numerous significant contrasts in cytokine-producing T-cell phenotypes were observed after infection in vaccinated and infected versus infected-only animals. These results suggest that vaccine-induced STM-specific cytokine-producing CD4+ T cells contribute to local immunity in the gut and may limit the spread of STM to lymph nodes and systemic organs. Hence, our study provides insights into the underlying immune mechanisms that account for the efficacy of the Salmoporc vaccine.

scholarly journals CRTAM determines the CD4+ cytotoxic T lymphocyte lineage

2015 ◽  
Vol 213 (1) ◽  
pp. 123-138 ◽  
Author(s):  
Arata Takeuchi ◽  
Mohamed El Sherif Gadelhaq Badr ◽  
Kosuke Miyauchi ◽  
Chitose Ishihara ◽  
Reiko Onishi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic Activity ◽  
Cd4 T Cells ◽  
Intracellular Signaling ◽  
Ectopic Expression ◽  
T Cell Subsets ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Ifn Γ

Naive T cells differentiate into various effector T cells, including CD4+ helper T cell subsets and CD8+ cytotoxic T cells (CTL). Although cytotoxic CD4+ T cells (CD4+CTL) also develop from naive T cells, the mechanism of development is elusive. We found that a small fraction of CD4+ T cells that express class I–restricted T cell–associated molecule (CRTAM) upon activation possesses the characteristics of both CD4+ and CD8+ T cells. CRTAM+ CD4+ T cells secrete IFN-γ, express CTL-related genes, such as eomesodermin (Eomes), Granzyme B, and perforin, after cultivation, and exhibit cytotoxic function, suggesting that CRTAM+ T cells are the precursor of CD4+CTL. Indeed, ectopic expression of CRTAM in T cells induced the production of IFN-γ, expression of CTL-related genes, and cytotoxic activity. The induction of CD4+CTL and IFN-γ production requires CRTAM-mediated intracellular signaling. CRTAM+ T cells traffic to mucosal tissues and inflammatory sites and developed into CD4+CTL, which are involved in mediating protection against infection as well as inducing inflammatory response, depending on the circumstances, through IFN-γ secretion and cytotoxic activity. These results reveal that CRTAM is critical to instruct the differentiation of CD4+CTL through the induction of Eomes and CTL-related gene.

scholarly journals Protective Vaccine Efficacy of the Complete Form of PPE39 Protein from Mycobacterium tuberculosis Beijing/K Strain in Mice

2017 ◽  
Vol 24 (11) ◽  
Author(s):  
Ahreum Kim ◽  
Yun-Gyoung Hur ◽  
Sunwha Gu ◽  
Sang-Nae Cho
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
T Cell ◽  
Vaccine Development ◽  
Protective Efficacy ◽  
Interleukin 2 ◽  
T Cell Epitopes ◽  
Content Type ◽  
Complete Form ◽  
Ifn Γ

ABSTRACT The aim of this study was to evaluate the protective efficacy of MTBK_24820, a complete form of PPE39 protein derived from a predominant Beijing/K strain of Mycobacterium tuberculosis in South Korea. Mice were immunized with MTKB_24820, M. bovis Bacilli Calmette-Guérin (BCG), or adjuvant prior to a high-dosed Beijing/K strain aerosol infection. After 4 and 9 weeks, bacterial loads were determined and histopathologic and immunologic features in the lungs and spleens of the M. tuberculosis-infected mice were analyzed. Putative immunogenic T-cell epitopes were examined using synthetic overlapping peptides. Successful immunization of MTBK_24820 in mice was confirmed by increased IgG responses (P < 0.05) and recalled gamma interferon (IFN-γ), interleukin-2 (IL-2), IL-6, and IL-17 responses (P < 0.05 or P < 0.01) to MTBK_24820. After challenge with the Beijing/K strain, an approximately 0.5 to 1.0 log10 reduction in CFU in lungs and fewer lung inflammation lesions were observed in MTBK_24820-immunized mice compared to those for control mice. Moreover, MTBK_24820 immunization elicited significantly higher numbers of CD4+ T cells producing protective cytokines, such as IFN-γ and IL-17, in lungs and spleens (P < 0.01) and CD4+ multifunctional T cells producing IFN-γ, tumor necrosis factor alpha (TNF-α), and/or IL-17 (P < 0.01) than in control mice, suggesting protection comparable to that of BCG against the hypervirulent Beijing/K strain. The dominant immunogenic T-cell epitopes that induced IFN-γ production were at the N terminus (amino acids 85 to 102 and 217 to 234). Its vaccine potential, along with protective immune responses in vivo, may be informative for vaccine development, particularly in regions where the M. tuberculosis Beijing/K-strain is frequently isolated from TB patients.

Targeting bioenergetics prevents CD4 T cell–mediated activation of synovial fibroblasts in rheumatoid arthritis

Rheumatology ◽  
2020 ◽  
Vol 59 (10) ◽  
pp. 2816-2828 ◽  
Author(s):  
Andreea Petrasca ◽  
James J Phelan ◽  
Sharon Ansboro ◽  
Douglas J Veale ◽  
Ursula Fearon ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adhesion Molecule ◽  
Cd4 T Cells ◽  
Reciprocal Relationship ◽  
Angiogenic Factor ◽  
Flux Analysis ◽  
Intracellular Cytokines ◽  
Tnf Α ◽  
Ifn Γ

Abstract Objectives We investigated the reciprocal relationship linking fibroblast-like synoviocytes (FLS) and T lymphocytes in the inflamed RA synovium and subsequently targeted cellular metabolic pathways in FLS to identify key molecular players in joint inflammation. Methods RA FLS were cultured with CD4 T cells or T cell conditioned medium (CD4CM); proliferation, expression of adhesion molecules and intracellular cytokines were examined by flow cytometry. FLS invasiveness and secreted cytokines were measured by transwell matrigel invasion chambers and ELISA, while metabolic profiles were determined by extracellular Seahorse flux analysis. Gene expression was quantified by real-time quantitative RT-PCR. Results Our results showed mutual activation between CD4 T cells and FLS, which resulted in increased proliferation and expression of intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 by both CD4 T cells and FLS. Furthermore, interaction between CD4 T cells and FLS resulted in an increased frequency of TNF-α+, IFN-γ+ and IL-17A+ CD4 T cells and augmented TNF-α, IFN-γ, IL-17A, IL-6, IL-8 and VEGF secretion. Moreover, CD4CM promoted invasiveness and boosted glycolysis in FLS while downregulating oxidative phosphorylation, effects paralleled by increased glucose transporters GLUT1 and GLUT3; key glycolytic enzymes GSK3A, HK2, LDHA and PFKFB3; angiogenic factor VEGF and MMP-3 and MMP-9. Importantly, these effects were reversed by the glycolytic inhibitor 2-DG and AMP analogue 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). Conclusion This study demonstrates that CD4 T cells elicit an aggressive phenotype in FLS, which subsequently upregulate glycolysis to meet the increased metabolic demand. Accordingly, 2-DG and AICAR prevent this activation, suggesting that glycolytic manipulation could have clinical implications for RA treatment.

Transcription Factor BACH2 Inhibits AP1 Proteins JunB and FosL1 in Umbilical Cord Blood (UCB) CD4+ T-Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1743-1743
Author(s):  
Mathew L. Lesniewski ◽  
Laura R. Fanning ◽  
Margeret Kozik ◽  
Richard P. Weitzel ◽  
Yeal Hegerfeldt ◽  
...  
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
Transcription Factor ◽  
T Cell ◽  
Cd4 T Cells ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Tnf Α ◽  
Ifn Γ ◽  
Sirna Knockdown

Abstract Introduction: Umbilical cord blood (UCB) CD4+ T-cells have been shown to express significant levels of BACH2 transcription factor protein compared to adult blood (AB) CD4+ T-cells. Previously, NFAT1 siRNA knockdown of UCB T-cells exhibited a significantly higher BACH2 mRNA expression, and IFN-γ, TNF-α. and CTLA-4 mRNA levels were significantly suppressed. BACH2, a member of the b-Zip family, has been shown to act as a heterodimer with the bZip protein MafK, as a transcriptional inhibitor via recruitment of a histone deacetylase class II complex (HDAC II) in differentiating B-cells, and neurons. Due to observed inverse expression of BACH2 and NFAT1 in UCB CD4+ T-cells, we hypothesized that BACH2 may regulate transcription factors known to bind with NFAT1 including AP-1 proteins JunB and FosL1. We tested this by siRNA knockdown of BACH2 in primary UCB-derived CD4+ T-cells. Key developmental transcription factors JUNB, FosL1, NFAT1 and downstream IFN-γ, and TNF-α were mRNA analyzed. Methods: UCB T-cells were purified using autoMACs system (Miltenyi). After overnight culture, T-cells were transfected with BACH2 siRNA (Dharmacon) using Amaxa Nucleofector system (Amaxa Inc). Both siRNA treated and control cells were incubated in media for 18 hours, and then stimulated using anti-CD3/anti-CD28 antibodies (BD BioScience). Aliquots of cells were collected at specified time points post-stimulation for protein and total RNA isolation. The relative change in mRNA levels for BACH2, JUNB, FosL1, IFN-γ, NFAT1, and TNF-α were determined by Lightcycler SybrGreen real time RT-PCR system (Roche). siRNA knockdown of BACH2 protein in transfected UCB T-cells was confirmed by western blot. Results: Real-time RT-PCR of BACH2 siRNA treated UCB CD4+ T-cells stimulated with anti-CD3/CD28 antibodies and analyzed after 6 hrs of stimulation showed a 4 log increase in FosL1 and NFAT1 mRNA, a 3 log increase in JunB mRNA, a 5 log increase in IFN-γ as compared to stimulated control UCB T-cells. TNF-α mRNA was decreased by 5 logs in BACH2 siRNA treated UCB T-cells as compared to control. CD3/CD28 stimulated untransfected UCB T-cells were previously shown to have decrease expression of NFAT1, JunB, FosL1, IFN-γ, and TNF-α, and in UCB T-cells compared to stimulated AB T-cells. Conclusions: BACH2 expression correlates with an inhibition of expression of AP1 transcription regulatory proteins in UCB T-cells during primary CD3/CD28 stimulation. The complete activation of the T-cell requires the activation of AP1 by CD28 pathway otherwise the antigen presenting cell signals the T-cell to enter anergy. In UCB CD4+ T-cells express BACH2, which acts as a transcriptional inhibitor of two critical AP1 genes, JUNB and FosL1, which mediate the CD28 co-stimulatory pathway. These results further suggests that expression of BACH2 in UCB T-cells may contribute to lower incidence of alloreactivity observed in leukemia patients receiving UCB stem cells compared to AB bone marrow stem cells and thus leads to low GVHD, and contribute to the weak Th1 response seen in stimulated UCB T-cells by reduced amounts of AP1 protein available for activating the T-cell.

scholarly journals TNF-α Regulates Mast Cell Functions by Inhibiting Cell Degranulation

2017 ◽  
Vol 44 (2) ◽  
pp. 751-762 ◽  
Author(s):  
Yuwei Gao ◽  
Baixue Xu ◽  
Peng Zhang ◽  
Yanlong He ◽  
Xin Liang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mast Cells ◽  
Cd4 T Cells ◽  
Cell Function ◽  
Mapk Signaling ◽  
Cell Functions ◽  
Tnf Α ◽  
Ifn Γ ◽  
Stimulation Of

Background/Aims: The aim of this study was to investigate the involvement of inducible co-stimulatory ligand (ICOSL) expression in stimulation of mast cells (MCs) by TNF-α and the ability of TNF-α stimulation of MCs to influence CD4+ T cell differentiation and function. The mechanisms underlying TNF-α stimulation of MCs were also explored. Methods: Mast cells and CD4+ T cells were prepared from C57BL/6 mice (aged 6–8 weeks). ICOSL expression by MCs was measured by real-time PCR and flow cytometry, and levels of IL-4, IL-10 and IFN-γ were measured by ELISA. Results: ICOSL expression by MCs was increased by TNF-α stimulation, and resulted in interaction with CD4+ T cells. The IL-4 and IL-10 levels in the co-culture system increased, while IFN-γ levels decreased. Furthermore, CD4+CD25+Foxp3+ T cell proliferation was induced by co-culture with TNF-α-stimulated MCs. The mechanism by which TNF-α stimulated MCs was dependent on the activation of the MAPK signaling pathway. Conclusion: TNF-α upregulated the expression of ICOSL on mast cells via a mechanism that is dependent on MAPK phosphorylation. TNF-α-treated MCs promoted the differentiation of regulatory T cells and induced a shift in cytokine expression from a Th1 to a Th2 profile by up-regulation ICOSL expression and inhibition of MC degranulation. Our study reveals a novel mechanism by which mast cells regulate T cell function.

scholarly journals The Role of β-Catenin in Th1 Immune Response against Tuberculosis and Profiles of Expression in Patients with Pulmonary Tuberculosis

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Kunlong Xiong ◽  
Jinxia Niu ◽  
Ruijuan Zheng ◽  
Zhonghua Liu ◽  
Yanzheng Song ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Mononuclear Cells ◽  
Cd4 T Cell ◽  
Cell Frequency ◽  
Tnf Α ◽  
Ifn Γ

β-Catenin is a key molecule of canonical Wnt/β-catenin pathway. Its roles and expression profiles in T cells of tuberculosis (TB) remain unclear. The aim of this study was to explore the role of β-catenin in CD4+ T cells and its expression characteristics in patients with pulmonary tuberculosis (PTB). In this study, CD4+ T cell-specific β-catenin conditional knockout mice (β-CAT-cKO mice) were aerosol infected with Mycobacteria tuberculosis (Mtb) H37RV with wild-type mice as controls. Four weeks after infection, the mRNA expression of IFN-γ, TNF-α, and TCF-7 in the lungs of mice was measured. CD4, CD8, β-catenin, IFN-γ, and TNF-α in mononuclear cells from the lungs and spleens were measured by flow cytometry, and the pathological changes of lungs were also observed. Patients with PTB were enrolled, with blood samples collected and PBMCs isolated. The expressions of β-catenin, IFN-γ, TNF-α, and PD-1 in CD4+ and CD8+ T cells were measured by flow cytometry. Results showed a decreased frequency of and reduced IFN-γ/TNF-α mRNA expression and secretion by CD4+ T cells in the lungs of infected β-CAT-cKO mice compared with infected wild-type controls, and only slightly more inflammatory changes were observed in the lungs. β-catenin expressions in CD4+ and CD8+ T cells were significantly decreased in blood cells of patients with severe PTB compared with those in mild PTB. The stimulation of peripheral blood mononuclear cells (PBMCs) with lithium chloride (LiCl), a stimulant of β-catenin, resulted in the increase in CD4+ T cell frequency, as well as their secretion of IFN-γ and TNF-α. β-Catenin demonstrated a moderately positive correlation with PD-1 in CD4+ T cells. β-Catenin along with PD-1 and IFN-γ in CD4+ T cells had a high correlation with those in CD8+ T cells. In conclusion, β-catenin may be involved in the regulation of Th1 response and CD4+ T cell frequency in TB.

scholarly journals Interplay between IL-10, IFN-γ, IL-17A and PD-1 Expressing EBNA1-Specific CD4+ and CD8+ T Cell Responses in the Etiologic Pathway to Endemic Burkitt Lymphoma

Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5375
Author(s):  
Catherine S. Forconi ◽  
David H. Mulama ◽  
Priya Saikumar Lakshmi ◽  
Joslyn Foley ◽  
Juliana A. Otieno ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Burkitt Lymphoma ◽  
Cd4 T Cells ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
T Cell Subsets ◽  
Effector Memory ◽  
Healthy Children ◽  
Ifn Γ

Children diagnosed with endemic Burkitt lymphoma (eBL) are deficient in interferon-γ (IFN-γ) responses to Epstein–Barr Nuclear Antigen1 (EBNA1), the viral protein that defines the latency I pattern in this B cell tumor. However, the contributions of immune-regulatory cytokines and phenotypes of the EBNA1-specific T cells have not been characterized for eBL. Using a bespoke flow cytometry assay we measured intracellular IFN-γ, IL-10, IL-17A expression and phenotyped CD4+ and CD8+ T cell effector memory subsets specific to EBNA1 for eBL patients compared to two groups of healthy children with divergent malaria exposures. In response to EBNA1 and a malaria antigen (PfSEA-1A), the three study groups exhibited strikingly different cytokine expression and T cell memory profiles. EBNA1-specific IFN-γ-producing CD4+ T cell response rates were lowest in eBL (40%) compared to children with high malaria (84%) and low malaria (66%) exposures (p < 0.0001 and p = 0.0004, respectively). However, eBL patients did not differ in CD8+ T cell response rates or the magnitude of IFN-γ expression. In contrast, eBL children were more likely to have EBNA1-specific CD4+ T cells expressing IL-10, and less likely to have polyfunctional IFN-γ+IL-10+ CD4+ T cells (p = 0.02). They were also more likely to have IFN-γ+IL-17A+, IFN-γ+ and IL-17A+ CD8+ T cell subsets compared to healthy children. Cytokine-producing T cell subsets were predominantly CD45RA+CCR7+ TNAIVE-LIKE cells, yet PD-1, a marker of persistent activation/exhaustion, was more highly expressed by the central memory (TCM) and effector memory (TEM) T cell subsets. In summary, our study suggests that IL-10 mediated immune regulation and depletion of IFN-γ+ EBNA1-specific CD4+ T cells are complementary mechanisms that contribute to impaired T cell cytotoxicity in eBL pathogenesis.

CD8+CD28− T cells: key cytotoxic players impacting disease pathogenesis in chronic HBV infection

2019 ◽  
Vol 133 (17) ◽  
pp. 1917-1934
Author(s):  
Madhuparna Nandi ◽  
Sourina Pal ◽  
Sumantra Ghosh ◽  
Bidhan Chandra Chakraborty ◽  
Debangana Dey ◽  
...  
Keyword(s):  
T Cells ◽  
Chronic Hepatitis ◽  
T Cell ◽  
Hepatitis B ◽  
Chronic Hepatitis B ◽  
Peripheral Blood ◽  
Cd4 T Cells ◽  
Hepatitis B E Antigen ◽  
Tnf Α ◽  
Ifn Γ

Abstract During chronic hepatitis B (CHB), CD8+ T cells down-regulate CD28, the primary co-stimulation molecule for T-cell activation. Diverse functional attributes of CD8+CD28− T cells are suggested in various disease contexts. The present study aimed to characterize CD8+CD28− T cells in different phases of chronic Hepatitis B virus (HBV) infection (CHI)- Immune-tolerance (IT), Hepatitis B e-antigen-positive CHB (EP-CHB), Inactive carriers (IC) and Hepatitis B e-antigen-negative CHB (EN-CHB), to appraise their contribution in HBV-related disease pathophysiology. Flow cytometry analysis of T cells in peripheral blood of study subjects revealed enhanced CD8+CD28− T-cell accumulation in EP-/EN-CHB, compared with IT/IC and they expanded equivalently in HBV-specific and non-specific CD8+ T-cell compartments. Profound increase in CD8+CD28− T cells expressing perforin/granzyme-B/CD57/IFN-γ/TNF-α and markers of terminal differentiation were observed exclusively in EP-/EN-CHB. Further, activation with anti-NKG2D resulted in heightened IFN-γ/TNF-α production selectively from CD8+CD28− T cells, suggesting NKG2D-mediated alternative co-stimulation. CD8+CD28− T cells sorted from CHB patients induced enhanced apoptosis of peripheral blood mononuclear cells (PBMC), including CD4+ T cells. However, NKG2D-ligand (major histocompatibility complex class I chain-related molecule A/B (MICA/B)) was preferentially expressed by HBV-specific CD4+ T cells of CHB patients, making these cells a potential target to NKG2D-dependent CD8+CD28− T-cell killing. Both CD28+ and CD28− T cells in CHB expressed CXCR3 at similar levels and thus capable of homing to the liver. A positive correlation was seen between CD8+CD28− T-cell frequency and serum-alanine transaminase (ALT) levels and CHB-derived CD8+CD28− T cells caused pronounced cell death in HBV-transfected Huh7 cells. Immunofluorescence staining identified greater intrahepatic incidence of CD8+CD28− T cells but decline in CD4+ T cells in CHB than IC. Collectively, CD8+CD28− T cells demonstrated differential distribution and phenotypic/functional skewing in different CHI phases and contribute to disease progression by Perforin-Granzyme- or IFN-γ-TNF-α-mediated cytotoxicity while restraining antiviral immunity through NKG2D-dependent HBV-specific CD4+ T-cell depletion.

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