scholarly journals Absence of rapid T cell control corresponds with delayed viral clearance in hospitalised COVID-19 patients

2021 ◽  
Author(s):  
Mihaela Zlei ◽  
Igor A. Sidorov ◽  
Simone Joosten ◽  
Mirjam Heemskerk ◽  
Sebenzile K. Myeni ◽  
...  
Keyword(s):  
T Cell ◽  
Critical Illness ◽  
Neutralizing Antibodies ◽  
Severe Disease ◽  
Treatment Strategies ◽  
Underlying Mechanism ◽  
Viral Clearance ◽  
Cell Control ◽  
Immune Parameters ◽  
Immunological Mechanisms

Abstract SARS-CoV-2 viral load is associated with disease severity. A better understanding of immunological mechanisms involved in viral clearance is crucial to guide new therapeutic strategies. Here, we studied the timing of viral clearance in relation to 122 immune parameters in 150 hospitalized COVID-19 patients. Delayed viral clearance was associated with more severe disease, which occurred after the virus had been cleared in most cases. Paradoxically, delayed viral clearance was associated with over time higher maximum levels of SARS-CoV-2 specific IgG, IgA, and neutralizing antibodies, increased numbers of eosinophils, monocytes, and pro-inflammatory cyto-/chemokines. In contrast, early viral clearance and less critical illness correlated with higher levels of CD4 + and CD8 + T cells. Collectively, our data show that absence of rapid T cell control corresponds with delayed clearance and aberrant antibody and cytokine profiles. Viral clearance often precedes critical illness, which suggests immunopathology as underlying mechanism. These data can guide treatment strategies.

scholarly journals A Monovalent and Trivalent MVA-Based Vaccine Completely Protects Mice Against Lethal Venezuelan, Western, and Eastern Equine Encephalitis Virus Aerosol Challenge

2021 ◽  
Vol 11 ◽  
Author(s):  
Lisa Henning ◽  
Kathrin Endt ◽  
Robin Steigerwald ◽  
Michael Anderson ◽  
Ariane Volkmann
Keyword(s):  
T Cell ◽  
Neutralizing Antibodies ◽  
Viral Vector ◽  
Protective Efficacy ◽  
Phase 1 ◽  
Severe Disease ◽  
Clinical Signs ◽  
T Cell Responses ◽  
Vaccine Platform ◽  
Cell Responses

Venezuelan, eastern and western equine encephalitis viruses (EEV) can cause severe disease of the central nervous system in humans, potentially leading to permanent damage or death. Yet, no licensed vaccine for human use is available to protect against these mosquito-borne pathogens, which can be aerosolized and therefore pose a bioterror threat in addition to the risk of natural outbreaks. Using the mouse aerosol challenge model, we evaluated the immunogenicity and efficacy of EEV vaccines that are based on the modified vaccinia Ankara-Bavarian Nordic (MVA-BN®) vaccine platform: three monovalent vaccines expressing the envelope polyproteins E3-E2-6K-E1 of the respective EEV virus, a mixture of these three monovalent EEV vaccines (Triple-Mix) as a first approach to generate a multivalent vaccine, and a true multivalent alphavirus vaccine (MVA-WEV, Trivalent) encoding the polyproteins of all three EEVs in a single non-replicating MVA viral vector. BALB/c mice were vaccinated twice in a four-week interval and samples were assessed for humoral and cellular immunogenicity. Two weeks after the second immunization, animals were exposed to aerosolized EEV. The majority of vaccinated animals exhibited VEEV, WEEV, and EEEV neutralizing antibodies two weeks post-second administration, whereby the average VEEV neutralizing antibodies induced by the monovalent and Trivalent vaccine were significantly higher compared to the Triple-Mix vaccine. The same statistical difference was observed for VEEV E1 specific T cell responses. However, all vaccinated mice developed comparable interferon gamma T cell responses to the VEEV E2 peptide pools. Complete protective efficacy as evaluated by the prevention of mortality and morbidity, lack of clinical signs and viremia, was demonstrated for the respective monovalent MVA-EEV vaccines, the Triple-Mix and the Trivalent single vector vaccine not only in the homologous VEEV Trinidad Donkey challenge model, but also against heterologous VEEV INH-9813, WEEV Fleming, and EEEV V105-00210 inhalational exposures. These EEV vaccines, based on the safe MVA vector platform, therefore represent promising human vaccine candidates. The trivalent MVA-WEV construct, which encodes antigens of all three EEVs in a single vector and can potentially protect against all three encephalitic viruses, is currently being evaluated in a human Phase 1 trial.

The non-T-cell-inflamed tumor microenvironment: contributing factors and therapeutic solutions

2017 ◽  
Vol 1 (5) ◽  
pp. 447-456 ◽  
Author(s):  
Brendan L. Horton ◽  
Stefani Spranger
Keyword(s):  
T Cell ◽  
Tumor Cell ◽  
Signaling Pathways ◽  
Cd8 T Cells ◽  
Treatment Strategies ◽  
Predictive Biomarkers ◽  
Contributing Factors ◽  
T Cell Infiltration ◽  
Immunological Mechanisms ◽  
Number Of Patients

The recent successes of cancer immunotherapy, first and foremost checkpoint blockade therapy, illustrate the power of the immune system to control cancer. As the number of patients receiving this therapy is increasing, the number of patients being resistant or establishing resistance toward immunotherapy is also increasing. We, therefore, need to further understand the mechanisms mediate resistance in order to prevent or overcome those mechanisms. Increasing evidence is being reported that alterations in tumor cell-intrinsic signaling pathways, including the activation of the WNT/β-catenin pathway, are associated with blunted T-cell infiltration. Infiltration of tumor by CD8 T cells is one of the most predictive biomarkers for the response toward immunotherapy and therefore the notion that alterations of certain tumor cell-intrinsic signaling pathways might mediate resistance should be considered. Understanding the molecular and immunological mechanisms mediating resistance will ultimately facilitate the development of effective treatment strategies counteracting immune evasion.

scholarly journals Longitudinal characterization of humoral and cellular immunity in hospitalized COVID-19 patients reveal immune persistence up to 9 months after infection

2021 ◽  
Author(s):  
John Tyler Sandberg ◽  
Renata Varnaitė ◽  
Wanda Christ ◽  
Puran Chen ◽  
Jagadeeswara R. Muvva ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Cellular Immunity ◽  
Symptom Onset ◽  
Neutralizing Antibodies ◽  
Severe Disease ◽  
Neutralizing Antibody ◽  
Immune Memory ◽  
Humoral And Cellular Immunity ◽  
Cell Responses

AbstractBackgroundInsights into early, specific humoral and cellular responses to infection with SARS-CoV-2, as well as the persistence and magnitude of resulting immune memory is important amidst the ongoing pandemic. The combination of humoral and cellular immunity will most likely contribute to protection from reinfection or severe disease.MethodsHere, we conducted a longitudinal study on hospitalized moderate and severe COVID-19 patients from the acute phase of disease into convalescence at five- and nine-months post symptom onset. Utilizing flow cytometry, serological assays as well as B cell and T cell FluoroSpot assays, we assessed the magnitude and specificity of humoral and cellular immune memory during and after human SARS-CoV-2 infection.FindingsDuring acute COVID-19, we observed an increase in germinal center activity, a substantial expansion of antibodysecreting cells, and the generation of SARS-CoV-2-neutralizing antibodies. Despite gradually decreasing antibody levels, we show persistent, neutralizing antibody titers as well as robust specific memory B cell responses and polyfunctional T cell responses at five- and nine-months after symptom onset in both moderate and severe COVID-19 patients. Long-term SARS-CoV-2 specific responses were marked by preferential targeting of spike over nucleocapsid protein.ConclusionsOur findings describe the initiation and, importantly, persistence of cellular and humoral SARS-CoV-2 specific immunological memory in hospitalized COVID-19 patients long after recovery, likely contributing towards protection against reinfection.

scholarly journals Increased Pathogenicity and Virulence of Middle East Respiratory Syndrome Coronavirus Clade B In Vitro and In Vivo

2020 ◽  
Vol 94 (15) ◽  
Author(s):  
Yanqun Wang ◽  
Jing Sun ◽  
Xiaobo Li ◽  
Airu Zhu ◽  
Wenda Guan ◽  
...  
Keyword(s):  
T Cell ◽  
Middle East ◽  
Severe Disease ◽  
Adaptive Immune Response ◽  
Viral Clearance ◽  
Middle East Respiratory Syndrome ◽  
Clade B ◽  
Alignment Analysis

ABSTRACT Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe acute respiratory disease in humans. MERS-CoV strains from early epidemic clade A and contemporary epidemic clade B have not been phenotypically characterized to compare their abilities to infect cells and mice. We isolated the clade B MERS-CoV ChinaGD01 strain from a patient infected during the South Korean MERS outbreak in 2015 and compared the phylogenetics and pathogenicity of MERS-CoV EMC/2012 (clade A) and ChinaGD01 (clade B) in vitro and in vivo. Genome alignment analysis showed that most clade-specific mutations occurred in the orf1ab gene, including mutations that were predicted to be potential glycosylation sites. Minor differences in viral growth but no significant differences in plaque size or sensitivity to beta interferon (IFN-β) were detected between these two viruses in vitro. ChinaGD01 virus infection induced more weight loss and inflammatory cytokine production in human DPP4-transduced mice. Viral titers were higher in the lungs of ChinaGD01-infected mice than with EMC/2012 infection. Decreased virus-specific CD4+ and CD8+ T cell numbers were detected in the lungs of ChinaGD01-infected mice. In conclusion, MERS-CoV evolution induced changes to reshape its pathogenicity and virulence in vitro and in vivo and to evade adaptive immune response to hinder viral clearance. IMPORTANCE MERS-CoV is an important emerging pathogen and causes severe respiratory infection in humans. MERS-CoV strains from early epidemic clade A and contemporary epidemic clade B have not been phenotypically characterized to compare their abilities to infect cells and mice. In this study, we showed that a clade B virus ChinaGD01 strain caused more severe disease in mice, with delayed viral clearance, increased inflammatory cytokines, and decreased antiviral T cell responses, than the early clade A virus EMC/2012. Given the differences in pathogenicity of different clades of MERS-CoV, periodic assessment of currently circulating MERS-CoV is needed to monitor potential severity of zoonotic disease.

scholarly journals Targeting Interleukin-2-Inducible T-Cell Kinase (ITK) Differentiates GVL and GVHD in Allo-HSCT

2020 ◽  
Vol 11 ◽  
Author(s):  
Mahinbanu Mammadli ◽  
Weishan Huang ◽  
Rebecca Harris ◽  
Aisha Sultana ◽  
Ying Cheng ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Interleukin 2 ◽  
Treatment Strategies ◽  
Receptor Expression ◽  
Hematopoietic Stem ◽  
Target Organs ◽  
Donor T Cells ◽  
Inducible T Cell Kinase

Allogeneic hematopoietic stem cell transplantation is a potentially curative procedure for many malignant diseases. Donor T cells prevent disease recurrence via graft-versus-leukemia (GVL) effect. Donor T cells also contribute to graft-versus-host disease (GVHD), a debilitating and potentially fatal complication. Novel treatment strategies are needed which allow preservation of GVL effects without causing GVHD. Using murine models, we show that targeting IL-2-inducible T cell kinase (ITK) in donor T cells reduces GVHD while preserving GVL effects. Both CD8+ and CD4+ donor T cells from Itk-/- mice produce less inflammatory cytokines and show decrease migration to GVHD target organs such as the liver and small intestine, while maintaining GVL efficacy against primary B-cell acute lymphoblastic leukemia (B-ALL). Itk-/- T cells exhibit reduced expression of IRF4 and decreased JAK/STAT signaling activity but upregulating expression of Eomesodermin (Eomes) and preserve cytotoxicity, necessary for GVL effect. Transcriptome analysis indicates that ITK signaling controls chemokine receptor expression during alloactivation, which in turn affects the ability of donor T cells to migrate to GVHD target organs. Our data suggest that inhibiting ITK could be a therapeutic strategy to reduce GVHD while preserving the beneficial GVL effects following allo-HSCT treatment.

scholarly journals Protective efficacy of a SARS-CoV-2 DNA vaccine in wild-type and immunosuppressed Syrian hamsters

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Rebecca L. Brocato ◽  
Steven A. Kwilas ◽  
Robert K. Kim ◽  
Xiankun Zeng ◽  
Lucia M. Principe ◽  
...  
Keyword(s):  
Dna Vaccine ◽  
Neutralizing Antibodies ◽  
Protective Efficacy ◽  
Phase 1 ◽  
Severe Disease ◽  
Disease Model ◽  
Wild Type ◽  
Jet Injection ◽  
Syrian Hamsters ◽  
Dna Targeting

AbstractA worldwide effort to counter the COVID-19 pandemic has resulted in hundreds of candidate vaccines moving through various stages of research and development, including several vaccines in phase 1, 2 and 3 clinical trials. A relatively small number of these vaccines have been evaluated in SARS-CoV-2 disease models, and fewer in a severe disease model. Here, a SARS-CoV-2 DNA targeting the spike protein and delivered by jet injection, nCoV-S(JET), elicited neutralizing antibodies in hamsters and was protective in both wild-type and transiently immunosuppressed hamster models. This study highlights the DNA vaccine, nCoV-S(JET), we developed has a great potential to move to next stage of preclinical studies, and it also demonstrates that the transiently-immunosuppressed Syrian hamsters, which recapitulate severe and prolonged COVID-19 disease, can be used for preclinical evaluation of the protective efficacy of spike-based COVID-19 vaccines.

scholarly journals Modelling the interplay between the CD4$$^{+}$$/CD8$$^{+}$$ T-cell ratio and the expression of MHC-I in tumours

2021 ◽  
Vol 83 (1) ◽  
Author(s):  
Christian John Hurry ◽  
Alexander Mozeika ◽  
Alessia Annibale
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Critical Level ◽  
Cell Infiltration ◽  
Cytotoxic T Cell ◽  
Mhc I ◽  
Cell Ratio ◽  
T Cell Infiltration ◽  
Immunological Mechanisms ◽  
Tcr Repertoire

AbstractDescribing the anti-tumour immune response as a series of cellular kinetic reactions from known immunological mechanisms, we create a mathematical model that shows the CD4$$^{+}$$ + /CD8$$^{+}$$ + T-cell ratio, T-cell infiltration and the expression of MHC-I to be interacting factors in tumour elimination. Methods from dynamical systems theory and non-equilibrium statistical mechanics are used to model the T-cell dependent anti-tumour immune response. Our model predicts a critical level of MHC-I expression which determines whether or not the tumour escapes the immune response. This critical level of MHC-I depends on the helper/cytotoxic T-cell ratio. However, our model also suggests that the immune system is robust against small changes in this ratio. We also find that T-cell infiltration and the specificity of the intra-tumour TCR repertoire will affect the critical MHC-I expression. Our work suggests that the functional form of the time evolution of MHC-I expression may explain the qualitative behaviour of tumour growth seen in patients.

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