scholarly journals HCV-Specific T Cell Responses During and After Chronic HCV Infection

Viruses ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 645 ◽  
Author(s):  
Hendrik Luxenburger ◽  
Christoph Neumann-Haefelin ◽  
Robert Thimme ◽  
Tobias Boettler
Keyword(s):  
T Cell ◽  
Current Knowledge ◽  
Therapeutic Vaccine ◽  
Chronic Phase ◽  
T Cell Responses ◽  
Cell Recovery ◽  
Cell Responses ◽  
Immune Pressure ◽  
Cell Immunity

Hepatitis C virus (HCV)-specific T cell responses are closely linked to the clinical course of infection. While T cell responses in self-limiting infection are typically broad and multi-specific, they display several distinct features of functional impairment in the chronic phase. Moreover, HCV readily adapts to immune pressure by developing escape mutations within epitopes targeted by T cells. Much of our current knowledge on HCV-specific T cell responses has been gathered under the assumption that this might eventually pave the way for a therapeutic vaccine. However, with the development of highly efficient direct acting antivirals (DAAs), there is less interest in the development of a therapeutic vaccine for HCV and the scope of T cell research has shifted. Indeed, the possibility to rapidly eradicate an antigen that has persisted over years or decades, and has led to T cell exhaustion and dysfunction, provides the unique opportunity to study potential T cell recovery after antigen cessation in a human in vivo setting. Findings from such studies not only improve our basic understanding of T cell immunity but may also advance immunotherapeutic approaches in cancer or chronic hepatitis B and D infection. Moreover, in order to edge closer to the WHO goal of HCV elimination by 2030, a prophylactic vaccine is clearly required. Thus, in this review, we will summarize our current knowledge on HCV-specific T cell responses and also provide an outlook on the open questions that require answers in this field.

Glucocorticoids transform CD40-triggering of dendritic cells into an alternative activation pathway resulting in antigen-presenting cells that secrete IL-10

Blood ◽  
2000 ◽  
Vol 95 (10) ◽  
pp. 3162-3167 ◽  
Author(s):  
Delphine Rea ◽  
Cees van Kooten ◽  
Krista E. van Meijgaarden ◽  
Tom H. M. Ottenhoff ◽  
Cornelis J. M. Melief ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Alternative Activation ◽  
Activation Process ◽  
Th1 Cells ◽  
T Helper 1 ◽  
Antigen Uptake ◽  
Cell Responses ◽  
Cell Immunity

Dendritic cell (DC) activation through CD40-CD40 ligand interactions is a key regulatory step for the development of protective T-cell immunity and also plays an important role in the initiation of T-cell responses involved in autoimmune diseases and allograft rejection. In contrast to previous reports, we show that the immunosuppressive drug dexamethasone (DEX) redirects rather than simply blocks this DC activation process. We found that DCs triggered through CD40 in the presence of DEX were unable to acquire high levels of costimulatory, adhesion, and major histocompatibility complex class I and II molecules and failed to express the maturation marker CD83, whereas antigen uptake was not affected. Moreover, DEX strikingly modified the CD40-activated DC cytokine secretion profile by suppressing the production of the proinflammatory cytokine interleukin (IL)-12 and potentiating the secretion of the anti-inflammatory cytokine IL-10. Accordingly, DEX-exposed CD40-triggered DCs displayed a decreased T-cell allostimulatory potential and a dramatically impaired ability to activate cloned CD4+ T helper 1 (Th1) cells. Moreover, interaction between Th1 cells and these DCs rendered the T cells hyporesponsive to further antigen-specific restimulation. Collectively, our results demonstrate that DEX profoundly modulates CD40-dependent DC activation and suggest that the resulting alternatively activated DCs can be exploited for suppression of unwanted T-cell responses in vivo.

scholarly journals MHC Class I Presented T Cell Epitopes as Potential Antigens for Therapeutic Vaccine against HBV Chronic Infection

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Joseph D. Comber ◽  
Aykan Karabudak ◽  
Vivekananda Shetty ◽  
James S. Testa ◽  
Xiaofang Huang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Chronic Infection ◽  
Acute Infection ◽  
Therapeutic Vaccine ◽  
T Cell Responses ◽  
Hbv Infection ◽  
Mhc I ◽  
Cell Responses ◽  
Cell Immunity

Approximately 370 million people worldwide are chronically infected with hepatitis B virus (HBV). Despite the success of the prophylactic HBV vaccine, no therapeutic vaccine or other immunotherapy modality is available for treatment of chronically infected individuals. Clearance of HBV depends on robust, sustained CD8+ T activity; however, the limited numbers of therapeutic vaccines tested have not induced such a response. Most of these vaccines have relied on peptide prediction algorithms to identify MHC-I epitopes or characterization of T cell responses during acute infection. Here, we took an immunoproteomic approach to characterize MHC-I restricted epitopes from cells chronically infected with HBV and therefore more likely to represent the true targets of CD8+ T cells during chronic infection. In this study, we identified eight novel MHC-I restricted epitopes derived from a broad range of HBV proteins that were capable of activating CD8+ T cells. Furthermore, five of the eight epitopes were able to bind HLA-A2 and A24 alleles and activated HBV specific T cell responses. These epitopes also have potential as new tools to characterize T cell immunity in chronic HBV infection and may serve as candidate antigens for a therapeutic vaccine against HBV infection.

scholarly journals HIV-1–Specific Immunodominant T-Cell Responses Drive the Dynamics of HIV-1 Recombination Following Superinfection

2022 ◽  
Vol 12 ◽  
Author(s):  
Hui Zhang ◽  
Shuang Cao ◽  
Yang Gao ◽  
Xiao Sun ◽  
Fanming Jiang ◽  
...  
Keyword(s):  
Amino Acids ◽  
T Cell ◽  
Immune Escape ◽  
T Cell Responses ◽  
Cell Responses ◽  
Immune Pressure ◽  
Cellular Immune ◽  
Hiv 1 ◽  
Recombination Breakpoints

A series of HIV-1 CRF01_AE/CRF07_BC recombinants were previously found to have emerged gradually in a superinfected patient (patient LNA819). However, the extent to which T-cell responses influenced the development of these recombinants after superinfection is unclear. In this study, we undertook a recombination structure analysis of the gag, pol, and nef genes from longitudinal samples of patient LNA819. A total of 9 pol and 5 nef CRF01_AE/CRF07_BC recombinants were detected. The quasispecies makeup and the composition of the pol and nef gene recombinants changed continuously, suggestive of continuous evolution in vivo. T-cell responses targeting peptides of the primary strain and the recombination regions were screened. The results showed that Pol-LY10, Pol-RY9, and Nef-GL9 were the immunodominant epitopes. Pol-LY10 overlapped with the recombination breakpoints in multiple recombinants. For the LY10 epitope, escape from T-cell responses was mediated by both recombination with a CRF07_BC insertion carrying the T467E/T472V variants and T467N/T472V mutations originating in the CRF01_AE strain. In pol recombinants R8 and R9, the recombination breakpoints were located ~23 amino acids upstream of the RY9 epitope. The appearance of new recombination breakpoints harboring a CRF07_BC insertion carrying a R984K variant was associated with escape from RY9-specific T-cell responses. Although the Nef-GL9 epitope was located either within or 10~11 amino acids downstream of the recombination breakpoints, no variant of this epitope was observed in the nef recombinants. Instead, a F85V mutation originating in the CRF01_AE strain was the main immune escape mechanism. Understanding the cellular immune pressure on recombination is critical for monitoring the new circulating recombinant forms of HIV and designing epitope-based vaccines. Vaccines targeting antigens that are less likely to escape immune pressure by recombination and/or mutation are likely to be of benefit to patients with HIV-1.

scholarly journals EXTH-51. GENETICALLY STABLE POLIOVIRUS VECTOR PLATFORM FOR DIPG IMMUNOTHERAPY

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi93-vi93
Author(s):  
Matthias Gromeier ◽  
Mubeen Mosaheb ◽  
Elena Dobrikova ◽  
Michael Brown ◽  
Darell Bigner ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Viral Vector ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Anatomical Location ◽  
Cell Responses ◽  
Cell Immunity

Abstract Options for the immunotherapy of diffuse intrinsic pontine glioma (DIPG), due to its anatomical location and inherent therapy resistance, are limited. The histone 3.3(K27M) mutation in ~80% of such tumors offers a unique opportunity for immunotherapy intervention, as it defines a high affinity, HLA-A2-restricted tumor neoantigen that spontaneously elicits CD8+ T cell responses in DIPG patients. Immunizing against the H3.3(K27M) signature in the clinic has been challenging, as conventional approaches (i.e. peptide-conjugates administered with adjuvants) lack the costimulatory signals known to drive CD8+ effector T cell responses. Therefore, we built on a viral vector approach for engaging innate immune responses to virus infection specifically in antigen presenting cells. Viruses naturally engage innate immunity, induce antigen presentation, and mediate CD8 T cell priming against foreign antigens. Polioviruses can provide a context optimal for generating antigen-specific CD8 T cells, as they have natural tropism for dendritic cells, preeminent inducers of CD8 T cell immunity; elicit Th1-promoting inflammation; and lack interference with innate or adaptive immunity. However, notorious genetic instability and underlying neuropathogenicity has hampered poliovirus-based vector applications. We devised a strategy based on the polio:rhinovirus chimera PVSRIPO, devoid of viral neuropathogenicity after intracerebral inoculation in human subjects, for stable expression of exogenous antigens. PVSRIPO vectors infect, activate, and induce epitope presentation in DCs in vitro; recruit and activate DCs with Th1-dominant cytokine profiles at the injection site in vivo. They efficiently prime tumor antigen-specific CD8 T cells in vivo, induce CD8 T cell migration to the tumor site, delay tumor growth and enhance survival in syngeneic rodent tumor models. We are preparing a prototype PVSRIPO-derived vector delivering the H3.3(K27M) signature for clinical investigation.

scholarly journals Single-Dose Vaccination with a Hepatotropic Adeno-associated Virus Efficiently Localizes T Cell Immunity in the Liver with the Potential To Confer Rapid Protection against Hepatitis C Virus

2019 ◽  
Vol 93 (19) ◽  
Author(s):  
Zelalem A. Mekonnen ◽  
Branka Grubor-Bauk ◽  
Kieran English ◽  
Preston Leung ◽  
Makutiro G. Masavuli ◽  
...  
Keyword(s):  
T Cells ◽  
Hepatitis C ◽  
T Cell ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Effective Vaccine ◽  
Adeno Associated Virus ◽  
Cell Responses ◽  
Cell Immunity

ABSTRACT Hepatitis C virus (HCV) is a significant contributor to the global disease burden, and development of an effective vaccine is required to eliminate HCV infections worldwide. CD4+ and CD8+ T cell immunity correlates with viral clearance in primary HCV infection, and intrahepatic CD8+ tissue-resident memory T (TRM) cells provide lifelong and rapid protection against hepatotropic pathogens. Consequently, we aimed to develop a vaccine to elicit HCV-specific CD4+ and CD8+ T cells, including CD8+ TRM cells, in the liver, given that HCV primarily infects hepatocytes. To achieve this, we vaccinated wild-type BALB/c mice with a highly immunogenic cytolytic DNA vaccine encoding a model HCV (genotype 3a) nonstructural protein (NS5B) and a mutant perforin (pVAX-NS5B-PRF), as well as a recombinant adeno-associated virus (AAV) encoding NS5B (rAAV-NS5B). A novel fluorescent target array (FTA) was used to map immunodominant CD4+ T helper (TH) cell and cytotoxic CD8+ T cell epitopes of NS5B in vivo, which were subsequently used to design a KdNS5B451-459 tetramer and analyze NS5B-specific T cell responses in vaccinated mice in vivo. The data showed that intradermal prime/boost vaccination with pVAX-NS5B-PRF was effective in eliciting TH and cytotoxic CD8+ T cell responses and intrahepatic CD8+ TRM cells, but a single intravenous dose of hepatotropic rAAV-NS5B was significantly more effective. As a T-cell-based vaccine against HCV should ideally result in localized T cell responses in the liver, this study describes primary observations in the context of HCV vaccination that can be used to achieve this goal. IMPORTANCE There are currently at least 71 million individuals with chronic HCV worldwide and almost two million new infections annually. Although the advent of direct-acting antivirals (DAAs) offers highly effective therapy, considerable remaining challenges argue against reliance on DAAs for HCV elimination, including high drug cost, poorly developed health infrastructure, low screening rates, and significant reinfection rates. Accordingly, development of an effective vaccine is crucial to HCV elimination. An HCV vaccine that elicits T cell immunity in the liver will be highly protective for the following reasons: (i) T cell responses against nonstructural proteins of the virus are associated with clearance of primary infection, and (ii) long-lived liver-resident T cells alone can protect against malaria infection of hepatocytes. Thus, in this study we exploit promising vaccination platforms to highlight strategies that can be used to evoke highly functional and long-lived T cell responses in the liver for protection against HCV.

scholarly journals Protection from viral rebound after therapeutic vaccination with an adjuvanted DNA vaccine is associated with SIV-specific polyfunctional CD8 T cells in the blood and mesenteric lymph nodes

2020 ◽  
Author(s):  
Hillary C. Tunggal ◽  
Paul V. Munson ◽  
Megan A. O’Connor ◽  
Nika Hajari ◽  
Sandra E. Dross ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Dna Vaccine ◽  
Therapeutic Vaccine ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Viral Rebound ◽  
Cell Responses ◽  
Cell Immunity

AbstractA therapeutic vaccine that induces lasting control of HIV infection has the potential to eliminate the need for lifelong adherence to antiretroviral therapy (ART). This study investigated the efficacy of a therapeutic DNA vaccine delivered with a novel combination of adjuvants and immunomodulators to augment T cell immunity in the blood and gut-associated lymphoid tissue. In SIV-infected rhesus macaques, a DNA vaccine delivered by intradermal electroporation and expressing SIV Env, Gag, and Pol, and a combination of adjuvant plasmids expressing the catalytic A1 subunit of E. coli heat labile enterotoxin (LTA1), IL-12, IL-33, retinaldehyde dehydrogenase 2 and the immunomodulators soluble PD-1 and soluble CD80, significantly enhanced the breadth and magnitude of Gag-specific IFN-γ T cell responses when compared to controls that were mock vaccinated or received the same DNA vaccine delivered by Gene Gun with a single adjuvant, the E. coli heat labile enterotoxin, LT. Notably, the DNA vaccine and adjuvant combination protected 3/5 animals from viral rebound, compared to only 1/4 mock vaccinated animals and 1/5 animals that received the DNA vaccine and LT. The lower viral burden among controllers during analytical treatment interruption significantly correlated with higher polyfunctional CD8+ T-cells (CD8+ T cells expressing 3 or more effector functions) in both mesenteric lymph nodes and blood measured during ART and analytical treatment interruption. Interestingly, controllers also had lower viral loads during acute infection and ART suggesting that inherent host-viral interactions induced prior to ART initiation likely influenced the response to therapeutic vaccination. These data indicate that gut mucosal immune responses combined with effective ART may play a key role in containing residual virus post-ART and highlight the need for therapeutic vaccines and adjuvants that can restore functional quality of peripheral and mucosal T cell responses before and during ART.Author SummaryHIV has caused significant human disease and mortality since its emergence in the 1980s. Furthermore, although antiretroviral therapy (ART) effectively reduces viral replication, stopping ART leads to increased viral loads and disease progression in most HIV-infected people. A therapeutic vaccine could enable HIV-infected people to control their infection without ART, but none of the vaccines that were tested in clinical trials so far have induced long-lasting control of virus replication. Here, we used the SIV rhesus macaque model to test a therapeutic vaccine consisting of DNA expressing SIV proteins and a novel combination of adjuvants to boost virus-specific immune responses. We found that our vaccine strategy significantly enhanced SIV-specific T cell responses when compared to controls and protected 3/5 animals from viral rebound. We determined that lower levels of virus replication post-ART were associated with enhanced T cell immunity in the gut-draining lymph nodes and blood. Our study highlights the critical role of T cell immunity for control of SIV and HIV replication and demonstrates that a successful therapeutic vaccine for HIV will need to elicit potent T cell responses in both the blood and gut-associated tissues.

Glucocorticoids transform CD40-triggering of dendritic cells into an alternative activation pathway resulting in antigen-presenting cells that secrete IL-10

Blood ◽  
2000 ◽  
Vol 95 (10) ◽  
pp. 3162-3167 ◽  
Author(s):  
Delphine Rea ◽  
Cees van Kooten ◽  
Krista E. van Meijgaarden ◽  
Tom H. M. Ottenhoff ◽  
Cornelis J. M. Melief ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Alternative Activation ◽  
Activation Process ◽  
Th1 Cells ◽  
T Helper 1 ◽  
Antigen Uptake ◽  
Cell Responses ◽  
Cell Immunity

Abstract Dendritic cell (DC) activation through CD40-CD40 ligand interactions is a key regulatory step for the development of protective T-cell immunity and also plays an important role in the initiation of T-cell responses involved in autoimmune diseases and allograft rejection. In contrast to previous reports, we show that the immunosuppressive drug dexamethasone (DEX) redirects rather than simply blocks this DC activation process. We found that DCs triggered through CD40 in the presence of DEX were unable to acquire high levels of costimulatory, adhesion, and major histocompatibility complex class I and II molecules and failed to express the maturation marker CD83, whereas antigen uptake was not affected. Moreover, DEX strikingly modified the CD40-activated DC cytokine secretion profile by suppressing the production of the proinflammatory cytokine interleukin (IL)-12 and potentiating the secretion of the anti-inflammatory cytokine IL-10. Accordingly, DEX-exposed CD40-triggered DCs displayed a decreased T-cell allostimulatory potential and a dramatically impaired ability to activate cloned CD4+ T helper 1 (Th1) cells. Moreover, interaction between Th1 cells and these DCs rendered the T cells hyporesponsive to further antigen-specific restimulation. Collectively, our results demonstrate that DEX profoundly modulates CD40-dependent DC activation and suggest that the resulting alternatively activated DCs can be exploited for suppression of unwanted T-cell responses in vivo.

scholarly journals Hepatitis C Virus Structural Proteins Impair Dendritic Cell Maturation and Inhibit In Vivo Induction of Cellular Immune Responses

2003 ◽  
Vol 77 (20) ◽  
pp. 10862-10871 ◽  
Author(s):  
Pablo Sarobe ◽  
Juan José Lasarte ◽  
Aintzane Zabaleta ◽  
Laura Arribillaga ◽  
Ainhoa Arina ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Responses ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Cell Immunity ◽  
Cellular Immune

ABSTRACT Hepatitis C virus (HCV) chronic infection is characterized by low or undetectable cellular immune responses against HCV antigens. Some studies have suggested that HCV proteins manipulate the immune system by suppressing the specific antiviral T-cell immunity. We have previously reported that the expression of HCV core and E1 proteins (CE1) in dendritic cells (DC) impairs their ability to prime T cells in vitro. We show here that immunization of mice with immature DC transduced with an adenovirus encoding HCV core and E1 antigens (AdCE1) induced lower CD4+- and CD8+-T-cell responses than immunization with DC transduced with an adenovirus encoding NS3 (AdNS3). However, no differences in the strength of the immune response were detected when animals were immunized with mature DC subsequently transduced with AdCE1 or AdNS3. According to these findings, we observed that the expression of CE1 in DC inhibited the maturation caused by tumor necrosis factor alpha or CD40L but not that induced by lipopolysaccharide. Blockade of DC maturation by CE1 was manifested by a lower expression of maturation surface markers and was associated with a reduced ability of AdCE1-transduced DC to activate CD4+- and CD8+-T-cell responses in vivo. Our results suggest that HCV CE1 proteins modulate T-cell responses by decreasing the stimulatory ability of DC in vivo via inhibition of their physiological maturation pathways. These findings are relevant for the design of therapeutic vaccination strategies in HCV-infected patients.

scholarly journals HER2-LAMP vaccines effectively traffic to endolysosomal compartments and generate enhanced polyfunctional T cell responses that induce complete tumor regression

2020 ◽  
Vol 8 (1) ◽  
pp. e000258 ◽  
Author(s):  
Alan Chen Chen ◽  
Renhuan Xu ◽  
Tao Wang ◽  
Junping Wei ◽  
Xiao-Yi Yang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Tumor Regression ◽  
T Cell Responses ◽  
Immune Checkpoint Blockade ◽  
Cell Responses ◽  
Cell Immunity

BackgroundThe advent of immune checkpoint blockade antibodies has demonstrated that effective mobilization of T cell responses can cause tumor regression of metastatic cancers, although these responses are heterogeneous and restricted to certain histologic types of cancer. To enhance these responses, there has been renewed emphasis in developing effective cancer-specific vaccines to stimulate and direct T cell immunity to important oncologic targets, such as the oncogene human epidermal growth factor receptor 2 (HER2), expressed in ~20% of breast cancers (BCs).MethodsIn our study, we explored the use of alternative antigen trafficking through use of a lysosome-associated membrane protein 1 (LAMP) domain to enhance vaccine efficacy against HER2 and other model antigens in bothin vitroandin vivostudies.ResultsWe found that inclusion of this domain in plasmid vaccines effectively trafficked antigens to endolysosomal compartments, resulting in enhanced major histocompatibility complex (MHC) class I and II presentation. Additionally, this augmented the expansion/activation of antigen-specific CD4+ and CD8+ T cells and also led to elevated levels of antigen-specific polyfunctional CD8+ T cells. Significantly, vaccination with HER2-LAMP produced tumor regression in ~30% of vaccinated mice with established tumors in an endogenous model of metastatic HER2+ BC, compared with 0% of HER2-WT vaccinated mice. This therapeutic benefit is associated with enhanced tumor infiltration of activated CD4+ and CD8+ T cells.ConclusionsThese data demonstrate the potential of using LAMP-based endolysosomal trafficking as a means to augment the generation of polyfunctional, antigen-specific T cells in order to improve antitumor therapeutic responses using cancer antigen vaccines.

scholarly journals Enhanced Cellular Immunity in Macaques following a Novel Peptide Immunotherapy

2005 ◽  
Vol 79 (6) ◽  
pp. 3748-3757 ◽  
Author(s):  
S. Chea ◽  
C. J. Dale ◽  
R. De Rose ◽  
I. A. Ramshaw ◽  
S. J. Kent
Keyword(s):  
T Cell ◽  
Mononuclear Cells ◽  
De Novo ◽  
T Cell Responses ◽  
Peripheral Blood Mononuclear ◽  
Cell Responses ◽  
Cell Immunity ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Advances in treating and preventing AIDS depend on understanding how human immunodeficiency virus (HIV) is eliminated in vivo and on the manipulation of effective immune responses to HIV. During the development of assays quantifying the elimination of fluorescent autologous cells coated with overlapping 15-mer simian immunodeficiency virus (SIV) or HIV-1 peptides, we made a remarkable observation: the reinfusion of macaque peripheral blood mononuclear cells, or even whole blood, pulsed with SIV and/or HIV peptides generated sharply enhanced SIV- and HIV-1-specific T-cell immunity. Strong, broad CD4+- and CD8+-T-cell responses could be enhanced simultaneously against peptide pools spanning 87% of all SIV- and HIV-1-expressed proteins—highly desirable characteristics of HIV-specific immunity. De novo hepatitis C virus-specific CD4+- and CD8+-T-cell responses were generated in macaques by the same method. This simple technique holds promise for the immunotherapy of HIV and other chronic viral infections.

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