scholarly journals Hepatitis C Virus Inhibits Cell Surface Expression of HLA-DR, Prevents Dendritic Cell Maturation, and Induces Interleukin-10 Production

2008 ◽  
Vol 82 (7) ◽  
pp. 3320-3328 ◽  
Author(s):  
Kousuke Saito ◽  
Malika Ait-Goughoulte ◽  
Steven M. Truscott ◽  
Keith Meyer ◽  
Azra Blazevic ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Cell Surface ◽  
Immune Responses ◽  
Mhc Class Ii ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Hla Dr ◽  
Ifn Γ

ABSTRACT Hepatitis C virus (HCV) chronic infection is characterized by low-level or undetectable cellular immune responses against HCV antigens. HCV proteins have been shown to affect various intracellular events and modulate immune responses, although the precise mechanisms used to mediate these effects are not fully understood. In this study, we have examined the effect of HCV proteins on the modulation of major histocompatibility complex (MHC) class II expression and other functions important for antigen presentation in humans. Expression of an HCV1-2962 genomic clone (HCV-FL) in human fibrosarcoma cells (HT1080) inhibited gamma interferon (IFN-γ)-induced upregulation of human leukocyte antigen-DR (HLA-DR) cell surface expression. Furthermore, inhibition of promoter activities of MHC class II transactivator (CIITA), IFN-γ-activated site (GAS), and HLA-DR was observed in IFN-γ-inducible HT1080 cells expressing HCV-FL by in vitro reporter assays. Exposure of human monocyte-derived dendritic cells (DCs) to cell culture-grown HCV (HCVcc) genotype 1a (clone H77) or 2a (clone JFH1) significantly inhibited DC maturation and was associated with the production of IL-10. Furthermore, DCs exposed to HCVcc were impaired in their functional ability to stimulate antigen-specific CD4-positive (CD4+) and CD8+ T-cell responses. Taken together, our results indicated that HCV can have direct and/or indirect inhibitory effects on antigen-presenting cells, resulting in reduction of antigen-specific T-cell activation. These effects may account for or contribute to the low overall level of immunogenicity of HCV observed in chronically infected patients.

scholarly journals Hepatitis C Virus-Mediated Inhibition of Cathepsin S Increases Invariant-Chain Expression on Hepatocyte Surface

2012 ◽  
Vol 86 (18) ◽  
pp. 9919-9928 ◽  
Author(s):  
Hangeun Kim ◽  
Budhaditya Mazumdar ◽  
Sandip K. Bose ◽  
Keith Meyer ◽  
Adrian M. Di Bisceglie ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Mhc Class Ii ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Cathepsin S ◽  
Invariant Chain ◽  
Upstream Stimulatory Factor ◽  
Hla Dr ◽  
Chronic Hcv

Hepatocytes are the main source of hepatitis C virus (HCV) replication and contain the maximum viral load in an infected person. Chronic HCV infection is characterized by weak cellular immune responses to viral proteins. Cathepsin S is a lysosomal cysteine protease and controls HLA-DR–antigen complex presentation through the degradation of the invariant chain. In this study, we examined the effect of HCV proteins on cathepsin S expression and found it to be markedly decreased in dendritic cells (DCs) exposed to HCV or in hepatocytes expressing HCV proteins. The downregulation of cathepsin S was mediated by HCV core and NS5A proteins involving inhibition of the transcription factors interferon regulatory factor 1 (IRF-1) and upstream stimulatory factor 1 (USF-1) in gamma interferon (IFN-γ)-treated hepatocytes. Inhibition of cathepsin S by HCV proteins increased cell surface expression of the invariant chain. In addition, hepatocytes stably transfected with HCV core or NS5A inhibited HLA-DR expression. Together, these results suggested that HCV has an inhibitory role on cathepsin S-mediated major histocompatibility complex (MHC) class II maturation, which may contribute to weak immunogenicity of viral antigens in chronically infected humans.

scholarly journals A Next Generation Bivalent Human Ad5 COVID-19 Vaccine Delivering Both Spike and Nucleocapsid Antigens Elicits Th1 Dominant CD4+, CD8+ T-cell and Neutralizing Antibody Responses

2020 ◽  
Author(s):  
Adrian Rice ◽  
Mohit Verma ◽  
Annie Shin ◽  
Lise Zakin ◽  
Peter Sieling ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
Immune Responses ◽  
Cd8 T Cell ◽  
Surface Expression ◽  
Antibody Responses ◽  
Cell Surface Expression ◽  
Clinical Testing ◽  
Next Generation ◽  
Cell Responses

ABSTRACTIn response to the health crisis presented by the COVID-19 pandemic, rapid development of safe and effective vaccines that elicit durable immune responses is imperative. Recent reports have raised the concern that antibodies in COVID-19 convalescent patients may not be long lasting and thus even these individuals may require vaccination. Vaccine candidates currently in clinical testing have focused on the SARS-CoV-2 wild type spike (S) protein (S-WT) as the major antigen of choice and while pre-clinical and early clinical testing have shown that S elicits an antibody response, we believe the optimal vaccine candidate should be capable of inducing robust, durable T-cell responses as well as humoral responses. We report here on a next generation bivalent human adenovirus serotype 5 (hAd5) vaccine capable of inducing immunity in patients with pre-existing adenovirus immunity, comprising both an S sequence optimized for cell surface expression (S-Fusion) and a conserved nucleocapsid (N) antigen designed to be transported to the endosomal subcellular compartment, with the potential to generate durable immune protection. Our studies suggest that this bivalent vaccine is optimized for immunogenicity as evidenced by the following findings: (i) The optimized S-Fusion displayed improved S receptor binding domain (RBD) cell surface expression compared to S-WT where little surface expression was detected; (ii) the expressed RBD from S-Fusion retained conformational integrity and recognition by ACE2-Fc; (iii) the viral N protein modified with an enhanced T-cell stimulation domain (ETSD) localized to endosomal/lysosomal subcellular compartments for MHC I/II presentation; and (iv) these optimizations to S and N (S-Fusion and N-ETSD) generated enhanced de novo antigen-specific B cell and CD4+ and CD8+ T-cell responses in antigen-naive pre-clinical models. Both the T-cell and antibody immune responses to S and N demonstrated a T-helper 1 (Th1) bias. The antibody responses were neutralizing as demonstrated by two independent SARS-CoV-2 neutralization assays. Based on these findings, we are advancing this next generation bivalent hAd5 S-Fusion + N-ETSD vaccine as our lead clinical candidate to test for its ability to provide robust, durable cell-mediated and humoral immunity against SARS-CoV-2 infection. Further studies are ongoing to explore utilizing this vaccine construct in oral, intranasal, and sublingual formulations to induce mucosal immunity in addition to cell-mediated and humoral immunity. The ultimate goal of an ideal COVID-19 vaccine is to generate long-term T and B cell memory.

scholarly journals The Level of CD81 Cell Surface Expression Is a Key Determinant for Productive Entry of Hepatitis C Virus into Host Cells

2006 ◽  
Vol 81 (2) ◽  
pp. 588-598 ◽  
Author(s):  
George Koutsoudakis ◽  
Eva Herrmann ◽  
Stephanie Kallis ◽  
Ralf Bartenschlager ◽  
Thomas Pietschmann
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cell Surface ◽  
Surface Expression ◽  
Hcv Infection ◽  
Host Cells ◽  
Productive Infection ◽  
Cell Surface Expression ◽  
Type I ◽  
Cell Clones

ABSTRACT Recently a cell culture model supporting the complete life cycle of the hepatitis C virus (HCV) was developed. Searching for host cell determinants involved in the HCV replication cycle, we evaluated the efficiency of virus propagation in different Huh-7-derived cell clones. We found that Huh-7.5 cells and Huh7-Lunet cells, two former replicon cell clones that had been generated by removal of an HCV replicon by inhibitor treatment, supported comparable levels of RNA replication and particle production, whereas virus spread was severely impaired in the latter cells. Analysis of cell surface expression of CD81 and scavenger receptor class B type I (SR-BI), two molecules previously implicated in HCV entry, revealed similar expression levels for SR-BI, while CD81 surface expression was much higher on Huh-7.5 cells than on Huh7-Lunet cells. Ectopic expression of CD81 in Huh7-Lunet cells conferred permissiveness for HCV infection to a level comparable to that for Huh-7.5 cells. Modulation of CD81 cell surface density in Huh-7.5 cells by RNA interference indicated that a certain amount of this molecule (∼7 × 104 molecules per cell) is required for productive infection with a low dose of HCV. Consistent with this, we show that susceptibility to HCV infection depends on a critical quantity of CD81 molecules. While infection is restricted in cells expressing very small amounts of CD81, susceptibility rapidly rises within a narrow range of CD81 levels, reaching a plateau where higher expression does not further increase the efficiency of infection. Together these data indicate that a high density of cell surface-exposed CD81 is a key determinant for productive HCV entry into host cells.

scholarly journals Bordetella pertussis Infection of Primary Human Monocytes Alters HLA-DR Expression

2004 ◽  
Vol 72 (3) ◽  
pp. 1450-1462 ◽  
Author(s):  
Jennifer A. Shumilla ◽  
Vashti Lacaille ◽  
Tara M. C. Hornell ◽  
Jennifer Huang ◽  
Supraja Narasimhan ◽  
...  
Keyword(s):  
Cell Surface ◽  
Bordetella Pertussis ◽  
Whooping Cough ◽  
Surface Expression ◽  
Interleukin 10 ◽  
Cell Surface Expression ◽  
Human Monocytes ◽  
Pertussis Infection ◽  
Hla Dr ◽  
Ifn Γ

ABSTRACT Bordetella pertussis is the causative agent of whooping cough, a potentially lethal respiratory disease in children. In immunocompetent individuals, B. pertussis infection elicits an effective adaptive immune response driven by activated CD4+ T cells. However, live B. pertussis persists in the host for 3 to 4 weeks prior to clearance. Thus, B. pertussis appears to have evolved short-term mechanisms for immune system evasion. We investigated the effects of B. pertussis wild-type strain BP338 on antigen presentation in primary human monocytes. BP338 infection reduced cell surface expression of HLA-DR and CD86 but not that of major histocompatibility complex class I proteins. This change in cell surface HLA-DR expression reflected intracellular redistribution of HLA-DR. The proportion of peptide-loaded molecules was unchanged in infected cells, suggesting that intracellular retention occurred after peptide loading. Although B. pertussis infection of monocytes induced rapid and robust expression of interleukin-10 (IL-10), HLA-DR redistribution did not appear to be explained by increased IL-10 levels. BP338-infected monocytes exhibited reduced synthesis of HLA-DR dimers. Interestingly, those HLA-DR proteins that were generated appeared to be longer-lived than HLA-DR in uninfected monocytes. BP338 infection also prevented gamma interferon (IFN-γ) induction of HLA-DR protein synthesis. Using mutant strains of B. pertussis, we found that reduction in HLA-DR surface expression was due in part to the presence of pertussis toxin whereas the inhibition of IFN-γ induction of HLA-DR could not be linked to any of the virulence factors tested. These data demonstrate that B. pertussis utilizes several mechanisms to modulate HLA-DR expression.

Cell surface expression of functional hepatitis C virus E1 and E2 glycoproteins

FEBS Letters ◽  
2003 ◽  
Vol 546 (2-3) ◽  
pp. 385-390 ◽  
Author(s):  
Heidi E. Drummer ◽  
Anne Maerz ◽  
Pantelis Poumbourios
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cell Surface ◽  
Surface Expression ◽  
Cell Surface Expression

scholarly journals Humoral and CD4+ T helper (Th) cell responses to the hepatitis C virus non-structural 3 (NS3) protein: NS3 primes Th1-like responses more effectively as a DNA-based immunogen than as a recombinant protein

2001 ◽  
Vol 82 (6) ◽  
pp. 1299-1308 ◽  
Author(s):  
Una Lazdina ◽  
Catharina Hultgren ◽  
Lars Frelin ◽  
Margaret Chen ◽  
Karin Lodin ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Responses ◽  
T Helper ◽  
Cell Responses ◽  
Ns3 Protein ◽  
Antibody Titres ◽  
Ifn Γ

The non-structural 3 (NS3) protein is one of the most conserved proteins of hepatitis C virus, and T helper 1 (Th1)-like responses to NS3 in humans correlate with clearance of infection. Several studies have proposed that DNA-based immunizations are highly immunogenic and prime Th1-like responses, although few head-to-head comparisons with exogenous protein immunizations have been described. A full-length NS3/NS4A gene was cloned in eukaryotic vectors with expression directed to different subcellular compartments. Inbred mice were immunized twice in regenerating tibialis anterior (TA) muscles with either plasmid DNA or recombinant NS3 (rNS3). After two 100 μg DNA immunizations, specific antibody titres of up to 12960 were detected at week 5, dominated by IgG2a and IgG2b. NS3-specific CD4+ T cell responses in DNA-immunized mice peaked at day 13, as measured by proliferation and IL-2 and IFN-γ production. Mice immunized with 1–10 μg rNS3 without adjuvant developed antibody titres comparable to those of the DNA-immunized mice, but dominated instead by IgG1. CD4+ T cell responses in these mice showed peaks of IL-2 response at day 3 and IL-6 and IFN-γ responses at day 6. With adjuvant, rNS3 was around 10-fold more immunogenic with respect to speed and magnitude of the immune responses. Thus, immunization with rNS3 in adjuvant is superior to DNA immunization with respect to kinetics and quantity in priming specific antibodies and CD4+ T cells. However, as a DNA immunogen, NS3 elicits stronger Th1-like immune responses, whereas rNS3 primes a mixed Th1/Th2-like response regardless of the route, dose or adjuvant.

scholarly journals Hepatitis C Virus Affects Tuberculosis-Specific T Cells in HIV-Negative Patients

Viruses ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 101 ◽  
Author(s):  
Mohamed Ahmed El-Mokhtar ◽  
Sherein G. Elgendy ◽  
Abeer Sharaf Eldin ◽  
Elham Ahmed Hassan ◽  
Ali Abdel Azeem Hasan ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Cd4 T Cells ◽  
Hcv Infection ◽  
Hla Dr ◽  
Ifn Γ ◽  
The Impact

The occurrence of tuberculosis (TB) and hepatitis C virus (HCV) infections in the same patient presents a unique clinical challenge. The impact of HCV infection on the immune response to TB remains poorly investigated in TB+/HCV+ patients. This study was conducted to evaluate the impact of HCV on the T-cell-mediated immune response to TB in coinfected patients. Sixty-four patients with active TB infections were screened for coinfection with HCV. The expression of immune activation markers IFN-γ, CD38, and HLA-DR on TB-specific CD4+ T cells was evaluated by flow cytometry in TB-monoinfected patients, TB/HCV-coinfected patients, and healthy controls. IL-2, IL-4, IFN-γ, TNF-α, and IL-10 levels were measured using ELISA. The end-of-treatment response to anti-TB therapy was recorded for both patient groups. Significantly lower levels of CD4+IFN-γ+CD38+ and CD4+IFN-γ+HLA-DR+ T cells were detected in TB/HCV-coinfected patients compared to TB monoinfected patients and controls. TB+/HCV+-coinfected patients showed higher serum levels of IL-10. The baseline frequencies of TB-specific activated T-cell subsets did not predict the response to antituberculous therapy in TB+/HCV+ patients. We concluded that different subsets of TB-specific CD4+ T cells in TB/HCV-infected individuals are partially impaired in early-stage HCV infection. This was combined with increased serum IL-10 level. Such immune modulations may represent a powerful risk factor for disease progression in patients with HCV/TB coinfection.

scholarly journals Functional Analysis of Cell Surface-Expressed Hepatitis C Virus E2 Glycoprotein

1999 ◽  
Vol 73 (8) ◽  
pp. 6782-6790 ◽  
Author(s):  
Mike Flint ◽  
Joanne M. Thomas ◽  
Catherine M. Maidens ◽  
Christine Shotton ◽  
Shoshana Levy ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cell Surface ◽  
Influenza A ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Soluble Form ◽  
Fusion Peptides ◽  
Hydrophobic Amino Acids ◽  
Anchor Sequence

ABSTRACT Hepatitis C virus (HCV) glycoproteins E1 and E2, when expressed in eukaryotic cells, are retained in the endoplasmic reticulum (ER). C-terminal truncation of E2 at residue 661 or 715 (position on the polyprotein) leads to secretion, consistent with deletion of a proposed hydrophobic transmembrane anchor sequence. We demonstrate cell surface expression of a chimeric glycoprotein consisting of E2 residues 384 to 661 fused to the transmembrane and cytoplasmic domains of influenza A virus hemagglutinin (HA), termed E2661-HATMCT. The E2661-HATMCT chimeric glycoprotein was able to bind a number of conformation-dependent monoclonal antibodies and a recombinant soluble form of CD81, suggesting that it was folded in a manner comparable to “native” E2. Furthermore, cell surface-expressed E2661-HATMCT demonstrated pH-dependent changes in antigen conformation, consistent with an acid-mediated fusion mechanism. However, E2661-HATMCT was unable to induce cell fusion of CD81-positive HEK cells after neutral- or low-pH treatment. We propose that a stretch of conserved, hydrophobic amino acids within the E1 glycoprotein, displaying similarities to flavivirus and paramyxovirus fusion peptides, may constitute the HCV fusion peptide. We demonstrate that influenza virus can incorporate E2661-HATMCT into particles and discuss experiments to address the relevance of the E2-CD81 interaction for HCV attachment and entry.

scholarly journals Alphavirus-based hepatitis C virus therapeutic vaccines: can universal helper epitopes enhance HCV-specific cytotoxic T lymphocyte responses?

2019 ◽  
Vol 7 ◽  
pp. 251513551987467
Author(s):  
Georgia Koutsoumpli ◽  
Peng Peng Ip ◽  
Ilona Schepel ◽  
Baukje Nynke Hoogeboom ◽  
Annemarie Boerma ◽  
...  
Keyword(s):  
T Cells ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Immune Responses ◽  
Semliki Forest Virus ◽  
Intracellular Cytokine Staining ◽  
Target Antigen ◽  
Optimal Dosage ◽  
Therapeutic Vaccines

Background: Antigen-specific T cell immune responses play a pivotal role in resolving acute and chronic hepatitis C virus (HCV) infections. Currently, no prophylactic or therapeutic vaccines against HCV are available. We previously demonstrated the preclinical potency of therapeutic HCV vaccines based on recombinant Semliki Forest virus (SFV) replicon particles. However, clinical trials do not always meet the high expectations of preclinical studies, thus, optimization of vaccine strategies is crucial. In efforts to further increase the frequency of HCV-specific immune responses in the candidate SFV-based vaccines, the authors assessed whether inclusion of three strong, so-called universal helper T cell epitopes, and an endoplasmic reticulum localization, and retention signal (collectively termed sigHELP-KDEL cassette) could enhance HCV-specific immune responses. Methods: We included the sigHELP-KDEL cassette in two of the candidate SFV-based HCV vaccines, targeting NS3/4A and NS5A/B proteins. We characterized the new constructs in vitro for the expression and stability of the transgene-encoded proteins. Their immune efficacy with respect to HCV-specific immune responses in vivo was compared with the parental SFV vaccine expressing the corresponding HCV antigen. Further characterization of the functionality of the HCV-specific CD8+ T cells was assessed by surface and intracellular cytokine staining and flow cytometry analysis. Results: Moderate, but significantly, enhanced frequencies of antigen-specific immune responses were achieved upon lower/suboptimal dosage immunization. In optimal dosage immunization, the inclusion of the cassette did not further increase the frequencies of HCV-specific CD8+ T cells when compared with the parental vaccines and the frequencies of effector and memory populations were identical. Conclusion: We hypothesize that the additional effect of the sigHELP-KDEL cassette in SFV-based vaccines depends on the immunogenicity, nature, and stability of the target antigen expressed by the vaccine.

Interferon-γ Upregulates CCR5 Expression in Cord and Adult Blood Mononuclear Phagocytes

Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1137-1144 ◽  
Author(s):  
Deepa Hariharan ◽  
Steven D. Douglas ◽  
Benhur Lee ◽  
Jian-Ping Lai ◽  
Donald E. Campbell ◽  
...  
Keyword(s):  
Cell Surface ◽  
Hiv Infection ◽  
Chemokine Receptors ◽  
Surface Expression ◽  
Interferon Γ ◽  
Mononuclear Phagocytes ◽  
Cell Surface Expression ◽  
Ccr5 Expression ◽  
Hiv Entry ◽  
Ifn Γ

Abstract The C-C chemokine receptors CCR5 and CCR3 are fusion coreceptors for human immunodeficiency virus (HIV) entry into macrophages. The regulation of their expression influences infectivity by HIV. We report here that interferon-γ (IFN-γ) a cytokine that has bidirectional effects on HIV infection of macrophages, significantly upregulated CCR5 and CCR3 cell surface expression in human mononuclear phagocytes isolated from placental cord blood and adult peripheral blood. Monocytes treated with IFN-γ showed increased chemotaxis to the CCR5 ligands macrophage inflammatory protein-1 (MIP-1) and MIP-1β, confirming the functional relevance of IFN-γ–induced CCR5 expression. However, IFN-γ suppressed HIV entry into macrophages. Interestingly, we demonstrated that IFN-γ inhibited cell surface expression of CD4, the major receptor for HIV. This finding may explain the suppressive effect of IFN-γ on HIV entry into macrophages, despite its enhancing effect on the expression of CCR5 and CCR3 by these cells. In addition, IFN-γ–induced secretion of C-C chemokines (RANTES, MIP-1, and MIP-1β) by mononuclear phagocytes may also suppress HIV entry into macrophages. These data provide further evidence for cytokine-mediated regulation of CCR5 expression and are consistent with a novel paradigm in which cytokines regulate HIV infection and leukocyte migration by reciprocal and opposing effects on the expression of CD4 and chemokine receptors.

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