scholarly journals Highly functional virus-specific cellular immune response in asymptomatic SARS-CoV-2 infection

2020 ◽  
Author(s):  
Nina Le Bert ◽  
Hannah E Clapham ◽  
Anthony T Tan ◽  
Wan Ni Chia ◽  
Christine YL Tham ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Inflammatory Cytokines ◽  
T Cell Activation ◽  
Cellular Immune Response ◽  
Cell Activation ◽  
Tnf Α ◽  
Specific Cellular Immune Response ◽  
Ifn Γ ◽  
Cellular Immune

AbstractThe efficacy of virus-specific T cells in clearing pathogens involves a fine balance between their antiviral and inflammatory features. SARS-CoV-2-specific T cells in individuals who clear SARS-CoV-2 infection without symptoms or disease could reveal non-pathological yet protective characteristics. We therefore compared the quantity and function of SARS-CoV-2-specific T cells in a cohort of asymptomatic individuals (n=85) with that of symptomatic COVID-19 patients (n=76), at different time points after antibody seroconversion. We quantified T cells reactive to structural proteins (M, NP and Spike) using ELISpot assays, and measured the magnitude of cytokine secretion (IL-2, IFN-γ, IL-4, IL-6, IL-1β, TNF-α and IL-10) in whole blood following T cell activation with SARS-CoV-2 peptide pools as a functional readout. Frequencies of T cells specific for the different SARS-CoV-2 proteins in the early phases of recovery were similar between asymptomatic and symptomatic individuals. However, we detected an increased IFN-γ and IL-2 production in asymptomatic compared to symptomatic individuals after activation of SARS-CoV-2-specific T cells in blood. This was associated with a proportional secretion of IL-10 and pro-inflammatory cytokines (IL-6, TNF-α and IL-1β) only in asymptomatic infection, while a disproportionate secretion of inflammatory cytokines was triggered by SARS-CoV-2-specific T cell activation in symptomatic individuals. Thus, asymptomatic SARS-CoV-2 infected individuals are not characterized by a weak antiviral immunity; on the contrary, they mount a robust and highly functional virus-specific cellular immune response. Their ability to induce a proportionate production of IL-10 might help to reduce inflammatory events during viral clearance.

scholarly journals Highly functional virus-specific cellular immune response in asymptomatic SARS-CoV-2 infection

2021 ◽  
Vol 218 (5) ◽  
Author(s):  
Nina Le Bert ◽  
Hannah E. Clapham ◽  
Anthony T. Tan ◽  
Wan Ni Chia ◽  
Christine Y.L. Tham ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell Activation ◽  
Cellular Immune Response ◽  
Cell Activation ◽  
Asymptomatic Infection ◽  
Tnf Α ◽  
Specific Cellular Immune Response ◽  
Ifn Γ ◽  
Cellular Immune

The efficacy of virus-specific T cells in clearing pathogens involves a fine balance between antiviral and inflammatory features. SARS-CoV-2–specific T cells in individuals who clear SARS-CoV-2 without symptoms could reveal nonpathological yet protective characteristics. We longitudinally studied SARS-CoV-2–specific T cells in a cohort of asymptomatic (n = 85) and symptomatic (n = 75) COVID-19 patients after seroconversion. We quantified T cells reactive to structural proteins (M, NP, and Spike) using ELISpot and cytokine secretion in whole blood. Frequencies of SARS-CoV-2–specific T cells were similar between asymptomatic and symptomatic individuals, but the former showed an increased IFN-γ and IL-2 production. This was associated with a proportional secretion of IL-10 and proinflammatory cytokines (IL-6, TNF-α, and IL-1β) only in asymptomatic infection, while a disproportionate secretion of inflammatory cytokines was triggered by SARS-CoV-2–specific T cell activation in symptomatic individuals. Thus, asymptomatic SARS-CoV-2–infected individuals are not characterized by weak antiviral immunity; on the contrary, they mount a highly functional virus-specific cellular immune response.

scholarly journals Adenovirus Vector Harboring the HBcAg and Tripeptidyl Peptidase II Genes Induces Potent Cellular Immune Responses In Vivo

2017 ◽  
Vol 41 (2) ◽  
pp. 423-438 ◽  
Author(s):  
Quanhui Tan ◽  
Siyuan Ma ◽  
Jianjun Hu ◽  
Xiaohua Chen ◽  
Yongsheng Yu ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Hepatitis B ◽  
Transgenic Mice ◽  
Immune Responses ◽  
Cellular Immune Response ◽  
Specific Cellular Immune Response ◽  
Ifn Γ ◽  
Cellular Immune

Background: Chronic hepatitis B virus (HBV) infection is associated with a weak but specific cellular immune response of the host to HBV. Tripeptidyl peptidaseⅡ (TPPⅡ), an intracellular macromolecule and proteolytic enzyme, plays an important complementary and compensatory role for the proteasome during viral protein degradation and major histocompatibility complex class I antigen presentation by inducing a specific cellular immune response in vivo. Based on a previous study, we aimed to explore the role of MHC class I antigen presentation in vivo and the mechanisms that may be involved. Methods: In this study, recombinant adenoviral vectors harboring the hepatitis B core antigen (HBcAg) and the TPPII gene were constructed (Adv-HBcAg and Adv-HBcAg-TPPII), and H-2Kd HBV-transgenic BALB/c mice and HLA-A2 C57BL/6 mice were immunized with these vectors, respectively. We evaluated the specific immune responses induced by Adv-HBcAg-TPPII in the HBV transgenic BALB/c mice and HLA-A2 C57BL/6 mice as well as the anti-viral ability of HBV transgenic mice, and we explored the underlying mechanisms. Results: We found that immunization with Adv-HBcAg-TPPII induced the secretion of the cytokines interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) as well as the activities of IFN-γ-secreting CD8+ T cells and CD4+ T cells. In addition, HBcAg-specific CTL activity in C57/BL mice and HBV transgenic animals was significantly enhanced in the Adv-HBcAg-TPPII group. Furthermore, Adv-HBcAg-TPPII decreased the hepatitis B surface antigen (HBsAg) and HBV DNA levels and the amount of HBsAg and HBcAg in liver tissues. Moreover, Adv-HBcAg-TPPII enhanced the expression of T-box transcription factor (T-bet) and downregulated GATA-binding protein 3 (GATA-3) while increasing the expression levels of JAK2, STAT1, STAT4 and Tyk2. Conclusions: These results suggested that the JAK/STAT signaling pathway participates in the CTL response that is mediated by the adenoviral vector encoding TPPII. Adv-HBcAg-TPPII could therefore break immune tolerance and stimulate HBV-specific cytotoxic T lymphocyte activity and could have a good therapeutic effect in transgenic mice.

scholarly journals CCL19 enhances CD8+ T-cell responses and accelerates HBV clearance

2021 ◽  
Author(s):  
Yan Yan ◽  
Wei Zhao ◽  
Wei Liu ◽  
Yan Li ◽  
Xu Wang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Crucial Role ◽  
Cell Activation ◽  
Hbv Infection ◽  
Host Immune System ◽  
Tnf Α ◽  
Ifn Γ ◽  
High Level

Abstract Background Chemokine (C–C motif) ligand 19 (CCL19) is a leukocyte chemoattractant that plays a crucial role in cell trafficking and leukocyte activation. Dysfunctional CD8+ T cells play a crucial role in persistent HBV infection. However, whether HBV can be cleared by CCL19-activated immunity remains unclear. Methods We assessed the effects of CCL19 on the activation of PBMCs in patients with HBV infection. We also examined how CCL19 influences HBV clearance and modulates HBV-responsive T cells in a mouse model of chronic hepatitis B (CHB). In addition, C–C chemokine-receptor type 7 (CCR7) knockdown mice were used to elucidate the underlying mechanism of CCL19/CCR7 axis-induced immune activation. Results From in vitro experiments, we found that CCL19 enhanced the frequencies of Ag-responsive IFN-γ+ CD8+ T cells from patients by approximately twofold, while CCR7 knockdown (LV-shCCR7) and LY294002 partially suppressed IFN-γ secretion. In mice, CCL19 overexpression led to rapid clearance of intrahepatic HBV likely through increased intrahepatic CD8+ T-cell proportion, decreased frequency of PD-1+ CD8+ T cells in blood and compromised suppression of hepatic APCs, with lymphocytes producing a significantly high level of Ag-responsive TNF-α and IFN-γ from CD8+ T cells. In both CCL19 over expressing and CCR7 knockdown (AAV-shCCR7) CHB mice, the frequency of CD8+ T-cell activation-induced cell death (AICD) increased, and a high level of Ag-responsive TNF-α and low levels of CD8+ regulatory T (Treg) cells were observed. Conclusions Findings in this study provide insights into how CCL19/CCR7 axis modulates the host immune system, which may promote the development of immunotherapeutic strategies for HBV treatment by overcoming T-cell tolerance.

scholarly journals Why intracellular parasitism need not be a degrading experience for Mycobacterium

1997 ◽  
Vol 352 (1359) ◽  
pp. 1303-1310 ◽  
Author(s):  
David G. Russell ◽  
Sheila Sturgill-Koszycki ◽  
Tambryn Vanheyningen ◽  
Helen Collins ◽  
Ulrich E. Schaible
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Biochemical Analysis ◽  
Hydrolytic Activity ◽  
Intracellular Pathogens ◽  
Tnf Α ◽  
Mycobacterial Diseases ◽  
Ifn Γ ◽  
Cellular Immune ◽  
Endosomal System

The success of mycobacteria as pathogens hinges on their ability to infect and persist within the macrophages of their host. However, activation of host macrophages by cytokines from a productive cellular immune response can stimulate the cells to kill their resident pathogens. This suggests that the interaction between host cell and microbe is in delicate balance, which can be tipped in favour of either organism. Biochemical analysis of mycobacterial vacuoles has shown them to be integral to the host cell's recycling endosomal system. As such they show limited acidification and hydrolytic activity despite possession of known lysosomal constituents such as cathepsins D, B and L, and LAMP 1. Even in established infections, they remain dynamic compartments accessible to several plasmalemma–derived constituents. Once the macrophage has been activated by IFN–γ and TNF–α the vacuoles coalesce and acidify. This marks a distinct alteration in vacuole physiology and leads to stasis and death of the mycobacteria. Mycobacteria have developed several strategies to avoid this outcome. Most notably, live bacilli induce sustained release of IL–6 from infected macrophages. IL–6 blocks the ability of both polyclonal primary T cells and T–cell hybridomas to respond to appropriate stimuli. Such an activity could render the centers of infection foci, such as granulomas, anergic and thus avoid release of macrophage–activating cytokines. This paper discusses both the mechanisms by which mycobacteria try to ensure their success as intracellular pathogens and the relevance of these strategies to the overall understanding of mycobacterial diseases.

scholarly journals HIV‐Specific Cellular Immune Response Is Inversely Correlated with Disease Progression as Defined by Decline of CD4+T Cells in Relation to HIV RNA Load

2004 ◽  
Vol 189 (7) ◽  
pp. 1199-1208 ◽  
Author(s):  
Annette Oxenius ◽  
David A. Price ◽  
Martin Hersberger ◽  
Erika Schlaepfer ◽  
Rainer Weber ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Disease Progression ◽  
Cellular Immune Response ◽  
Cd4 T Cells ◽  
Hiv Rna ◽  
Specific Cellular Immune Response ◽  
Cellular Immune

scholarly journals Methotrexate Hampers Immunogenicity to BNT162b2 mRNA COVID-19 Vaccine in Immune-Mediated Inflammatory Disease

2021 ◽  
Author(s):  
Rebecca H Haberman ◽  
Ramin Herati ◽  
David Simon ◽  
Marie Samanovic ◽  
Rebecca B. Blank ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell Activation ◽  
Cellular Immune Response ◽  
Healthy Subjects ◽  
Cell Activation ◽  
Inflammatory Diseases ◽  
Antibody Responses ◽  
Igg Antibody ◽  
Immune Mediated ◽  
Cellular Immune

Objective: To investigate the humoral and cellular immune response to mRNA COVID-19 vaccines in patients with immune-mediated inflammatory diseases (IMIDs) on immunomodulatory treatment. Methods: Established patients at NYU Langone Health with IMID (n=51) receiving the BNT162b2 mRNA vaccination were assessed at baseline and after second immunization. Healthy subjects served as controls (n=26). IgG antibody responses to the spike protein were analyzed for humoral response. Cellular immune response to SARS-CoV-2 was further analyzed using high-parameter spectral flow cytometry. A second independent, validation cohort of controls (n=182) and patients with IMID (n=31) from Erlangen, Germany were also analyzed for humoral immune response. Results: Although healthy subjects (n=208) and IMID patients on biologic treatments (mostly on TNF blockers, n=37) demonstrate robust antibody responses (over 90%), those patients with IMID on background methotrexate (n=45) achieve an adequate response in only 62.2% of cases. Similarly, IMID patients do not demonstrate an increase in CD8+ T cell activation after vaccination. Conclusions: In two independent cohorts of IMID patients, methotrexate, a widely used immunomodulator for the treatment of several IMIDs, adversely affected humoral and cellular immune response to COVID-19 mRNA vaccines. Although precise cut offs for immunogenicity that correlate with vaccine efficacy are yet to be established, our findings suggest that different strategies may need to be explored in patients with IMID taking methotrexate to increase the chances of immunization efficacy against SARS-CoV-2 as has been demonstrated for augmenting immunogenicity to other viral vaccines.

scholarly journals Differential CD147 Functional Epitopes on Distinct Leukocyte Subsets

2021 ◽  
Vol 12 ◽  
Author(s):  
Supansa Pata ◽  
Sirirat Surinkaew ◽  
Nuchjira Takheaw ◽  
Witida Laopajon ◽  
Kantinan Chuensirikulchai ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Function ◽  
Inflammatory Diseases ◽  
Cell Contact ◽  
Cell Functions ◽  
Tnf Α ◽  
Ifn Γ

CD147, a member of the immunoglobulin (Ig) superfamily, is widely expressed in several cell types. CD147 molecules have multiple cellular functions, such as migration, adhesion, invasion, energy metabolism and T cell activation. In particular, recent studies have demonstrated the potential application of CD147 as an effective therapeutic target for cancer, as well as autoimmune and inflammatory diseases. In this study, we elucidated the functional epitopes on CD147 extracellular domains in T cell regulation using specific monoclonal antibodies (mAbs). Upon T cell activation, the anti-CD147 domain 1 mAbs M6-1E9 and M6-1D4 and the anti-CD147 domain 2 mAb MEM-M6/6 significantly reduced surface expression of CD69 and CD25 and T cell proliferation. To investigate whether functional epitopes of CD147 are differentially expressed on distinct leukocyte subsets, PBMCs, monocyte-depleted PBMCs and purified T cells were activated in the presence of anti-CD147 mAbs. The mAb M6-1E9 inhibited T cell functions via activation of CD147 on monocytes with obligatory cell-cell contact. Engagement of the CD147 epitope by the M6-1E9 mAb downregulated CD80 and CD86 expression on monocytes and IL-2, TNF-α, IFN-γ and IL-17 production in T cells. In contrast, the mAb M6-1D4 inhibited T cell function via activation of CD147 on T cells by downregulating IL-2, TNF-α and IFN-γ. Herein, we demonstrated that certain epitopes of CD147, expressed on both monocytes and T cells, are involved in the regulation of T cell activation.

scholarly journals Kinetics of the Immune Response Profile in Guinea Pigs after Vaccination with Mycobacterium bovis BCG and Infection with Mycobacterium tuberculosis

2009 ◽  
Vol 77 (11) ◽  
pp. 4837-4846 ◽  
Author(s):  
Ajay Grover ◽  
Jennifer Taylor ◽  
JoLynn Troudt ◽  
Andrew Keyser ◽  
Kimberly Arnett ◽  
...  
Keyword(s):  
T Cells ◽  
Mrna Expression ◽  
Mycobacterium Bovis ◽  
T Cell Activation ◽  
Guinea Pigs ◽  
Cell Activation ◽  
Activated T Cells ◽  
Bcg Vaccination ◽  
Tnf Α ◽  
Ifn Γ

ABSTRACT The guinea pig model of tuberculosis is used extensively in assessing novel vaccines, since Mycobacterium bovis BCG vaccination effectively prolongs survival after low-dose aerosol infection with virulent M. tuberculosis. To better understand how BCG extends time to death after pulmonary infection with M. tuberculosis, we examined cytokine responses postvaccination and recruitment of activated T cells and cytokine response postinfection. At 10 weeks postvaccination, splenic gamma interferon (IFN-γ) mRNA was significantly elevated compared to the levels at 5 weeks in ex vivo stimulation assays. At 15, 40, 60, and 120 days postinfection, T-cell activation (CD4+ CD62Llow and CD8+ CD62Llow) and mRNA expression of IFN-γ, tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-10, IL-12, and eomesodermin were assessed. Our data show that at day 40, BCG-vaccinated guinea pigs had significantly increased levels of IFN-γ mRNA expression but decreased TNF-α mRNA expression in their lungs compared to the levels in nonvaccinated animals. At day 120, a time when nonvaccinated guinea pigs succumbed to infection, low levels of IFN-γ mRNA were observed even though there were increasing levels of IL-1, IL-12, and IL-10, and the numbers of activated T cells did not differ from those in BCG-vaccinated animals. BCG vaccination conferred the advantage of recruiting greater numbers of CD4+ CD62Llow T cells at day 40, although the numbers of CD8+ CD62Llow T cells were not elevated compared to the numbers in nonvaccinated animals. Our data suggest that day 40 postinfection may be a pivotal time point in determining vaccine efficacy and prolonged survival and that BCG promotes the capacity of T cells in the lungs to respond to infection.

IL-35 inhibits HBV antigen-specific IFN-γ-producing CTLs in vitro

2015 ◽  
Vol 129 (5) ◽  
pp. 395-404 ◽  
Author(s):  
Xuefen Li ◽  
Li Tian ◽  
Yuejiao Dong ◽  
Qiaoyun Zhu ◽  
Yiyin Wang ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Chronic Hepatitis ◽  
Hepatitis B ◽  
Chronic Hepatitis B ◽  
Cellular Immune Response ◽  
Cd4 T Cells ◽  
Ifn Γ ◽  
Cellular Immune

Inhibitory cytokine, interleukin-35 (IL-35), is highly expressed in CD4+ T-cells from CHB patients and plays an important role in the inhibition of the cellular immune response, which contribute to the development and progression of chronic hepatitis B.

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