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1.
J Immunol Methods ; 496: 113099, 2021 09.
Article in English | MEDLINE | ID: covidwho-1292808

ABSTRACT

Bispecific antibodies (BsAbs) are engineered to simultaneously bind two different antigens, and offer promising clinical outcomes for various diseases. The dual binding properties of BsAbs may enable superior efficacies and/or potencies compared to standard monoclonal antibodies (mAbs) or combination mAb therapies. Characterizing BsAb binding properties is critical during biotherapeutic development, where data is leveraged to predict efficacy and potency, assess critical quality attributes and improve antibody design. Traditional single-target, single-readout approaches (e.g., ELISA) have limited usefulness for interpreting complex bispecific binding, and double the benchwork. To address these deficiencies, we developed and implemented a new dual-target/readout binding assay that accurately dissects the affinities of both BsAb binding domains directly and simultaneously. This new assay uses AlphaPlex® technology, which eliminates traditional ELISA wash steps and can be miniaturized for automated workflows. The optimized BsAb AlphaPlex assay demonstrates 99-107% accuracy within a 50-150% linear range, and detected >50% binding degradation from photo- and thermal stress conditions. To the best of our knowledge, this is the first instance of a dual-target/readout BsAb AlphaPlex assay with GMP-suitable linear range, accuracy, specificity, and stability-indicating properties. As a highly customizable and efficient assay, BsAb AlphaPlex may be applicable to numerous bispecific formats and/or co-formulations against a variety of antigens beyond the clinical therapeutic space.


Subject(s)
Antibodies, Bispecific/immunology , Antibody Specificity , Antigens/immunology , CTLA-4 Antigen/immunology , Immunoassay , Programmed Cell Death 1 Receptor/immunology , Antibodies, Bispecific/metabolism , Antigen-Antibody Complex , Antigens/metabolism , Binding Sites, Antibody , Buffers , CTLA-4 Antigen/metabolism , Enzyme-Linked Immunosorbent Assay , Epitopes , Humans , Hydrogen-Ion Concentration , Kinetics , Predictive Value of Tests , Programmed Cell Death 1 Receptor/metabolism , Protein Binding , Reproducibility of Results
2.
Cell Immunol ; 364: 104347, 2021 06.
Article in English | MEDLINE | ID: covidwho-1157177

ABSTRACT

Myeloid-derived suppressor cells (MDSC) are important immune-regulatory cells but their identification remains difficult. Here, we provide a critical view on selected surface markers, transcriptional and translational pathways commonly used to identify MDSC by specific, their developmental origin and new possibilities by transcriptional or proteomic profiling. Discrimination of MDSC from their non-suppressive counterparts is a prerequisite for the development of successful therapies. Understanding the switch mechanisms that direct granulocytic and monocytic development into a pro-inflammatory or anti-inflammatory direction will be crucial for therapeutic strategies. Manipulation of these myeloid checkpoints are exploited by tumors and pathogens, such as M. tuberculosis (Mtb), HIV or SARS-CoV-2, that induce MDSC for immune evasion. Thus, specific markers for MDSC identification may reveal also novel molecular candidates for therapeutic intervention at the level of MDSC.


Subject(s)
Biomarkers/metabolism , Gene Expression Profiling/methods , Myeloid-Derived Suppressor Cells/immunology , Proteomics/methods , Signal Transduction/immunology , Animals , B7-H1 Antigen/genetics , B7-H1 Antigen/immunology , B7-H1 Antigen/metabolism , COVID-19/immunology , COVID-19/prevention & control , COVID-19/virology , Cells, Cultured , Humans , Mice , Myeloid-Derived Suppressor Cells/metabolism , Neoplasms/genetics , Neoplasms/immunology , Neoplasms/metabolism , Programmed Cell Death 1 Receptor/genetics , Programmed Cell Death 1 Receptor/immunology , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Signal Transduction/genetics , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism
3.
Front Immunol ; 12: 640644, 2021.
Article in English | MEDLINE | ID: covidwho-1133916

ABSTRACT

Infection with SARS-CoV-2 can lead to Coronavirus disease-2019 (COVID-19) and result in severe acute respiratory distress syndrome (ARDS). Recent reports indicate an increased rate of fungal coinfections during COVID-19. With incomplete understanding of the pathogenesis and without any causative therapy available, secondary infections may be detrimental to the prognosis. We monitored 11 COVID-19 patients with ARDS for their immune phenotype, plasma cytokines, and clinical parameters on the day of ICU admission and on day 4 and day 7 of their ICU stay. Whole blood stimulation assays with lipopolysaccharide (LPS), heat-killed Listeria monocytogenes (HKLM), Aspergillus fumigatus, and Candida albicans were used to mimic secondary infections, and changes in immune phenotype and cytokine release were assessed. COVID-19 patients displayed an immune phenotype characterized by increased HLA-DR+CD38+ and PD-1+ CD4+ and CD8+ T cells, and elevated CD8+CD244+ lymphocytes, compared to healthy controls. Monocyte activation markers and cytokines IL-6, IL-8, TNF, IL-10, and sIL2Rα were elevated, corresponding to monocyte activation syndrome, while IL-1ß levels were low. LPS, HKLM and Aspergillus fumigatus antigen stimulation provoked an immune response that did not differ between COVID-19 patients and healthy controls, while COVID-19 patients showed an attenuated monocyte CD80 upregulation and abrogated release of IL-6, TNF, IL-1α, and IL-1ß toward Candida albicans. This study adds further detail to the characterization of the immune response in critically ill COVID-19 patients and hints at an increased susceptibility for Candida albicans infection.


Subject(s)
Aspergillus fumigatus/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Candida albicans/immunology , Listeria monocytogenes/immunology , SARS-CoV-2/physiology , Aged , Cells, Cultured , Cytokines/metabolism , Disease Susceptibility , Female , Humans , Immune Tolerance , Male , Middle Aged , Programmed Cell Death 1 Receptor/metabolism , Respiratory Distress Syndrome
4.
Immunity ; 54(1): 44-52.e3, 2021 01 12.
Article in English | MEDLINE | ID: covidwho-1065202

ABSTRACT

Memory T cell responses have been demonstrated in COVID-19 convalescents, but ex vivo phenotypes of SARS-CoV-2-specific T cells have been unclear. We detected SARS-CoV-2-specific CD8+ T cells by MHC class I multimer staining and examined their phenotypes and functions in acute and convalescent COVID-19. Multimer+ cells exhibited early differentiated effector-memory phenotypes in the early convalescent phase. The frequency of stem-like memory cells was increased among multimer+ cells in the late convalescent phase. Cytokine secretion assays combined with MHC class I multimer staining revealed that the proportion of interferon-γ (IFN-γ)-producing cells was significantly lower among SARS-CoV-2-specific CD8+ T cells than those specific to influenza A virus. Importantly, the proportion of IFN-γ-producing cells was higher in PD-1+ cells than PD-1- cells among multimer+ cells, indicating that PD-1-expressing, SARS-CoV-2-specific CD8+ T cells are not exhausted, but functional. Our current findings provide information for understanding of SARS-CoV-2-specific CD8+ T cells elicited by infection or vaccination.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/immunology , Acute-Phase Reaction/immunology , Acute-Phase Reaction/virology , COVID-19/pathology , COVID-19/virology , Convalescence , Epitopes, T-Lymphocyte , Histocompatibility Antigens Class I/immunology , Humans , Immunologic Memory , Immunophenotyping , Interferon-gamma/metabolism , Lymphocyte Activation , Viral Load
5.
Life Sci ; 270: 119124, 2021 Apr 01.
Article in English | MEDLINE | ID: covidwho-1051825

ABSTRACT

The outbreak of SARS-CoV-2 in Wuhan of China in December 2019 and its worldwide spread has turned into the COVID-19 pandemic. Respiratory disorders, lymphopenia, cytokine cascades, and the immune responses provoked by this virus play a major and fundamental role in the severity of the symptoms and the immunogenicity which it causes. Owing to the decrease in the inflammatory responses' regulation in the immune system and the sudden increase in the secretion of cytokines, it seems that an investigation of inhibitory immune checkpoints can influence theories regarding this disease's treatment methods. Acquired cell-mediated immune defense's T-cells have a key major contribution in clearing viral infections thus reducing the severity of COVID-19's symptoms. The most important diagnostic feature in individuals with COVID-19 is lymphocyte depletion, most importantly, T-cells. Due to the induction of interferon-γ (INF-γ) production by neutrophils and monocytes, which are abundantly present in the peripheral blood of the individuals with COVID-19, the expression of inhibitory immune checkpoints including, PD-1 (programmed death), PD-L1 and CTLA4 on the T-cells' surface is enhanced. The purpose of this review is to discuss the functions of these checkpoints and their effects on the dysfunction and exhaustion of T-cells, making them almost ineffective in individuals with COVID-19, especially in the cases with extreme symptoms.


Subject(s)
B7-H1 Antigen/metabolism , COVID-19/immunology , CTLA-4 Antigen/metabolism , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/physiology , T-Lymphocytes/immunology , COVID-19/metabolism , Humans , Monocytes/immunology
6.
Cancer Immunol Res ; 9(3): 261-264, 2021 03.
Article in English | MEDLINE | ID: covidwho-1033549

ABSTRACT

The immunomodulatory effects of immune-checkpoint blockade (ICB) therapy for cancer may act at the crossroads between the need to increase antiviral immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to decrease the inflammatory responses in severe cases of coronavirus disease 2019 (COVID-19). There is evidence from preclinical models that blocking programmed death receptor 1 (PD1) protects against RNA virus infections, which suggests that patients with cancer receiving ICB may have lower rates of viral infection. However, given the heterogeneity of patient characteristics, this would be difficult to demonstrate using population-based registries or in clinical trials. Most studies of the impact of ICB therapy on the course of COVID-19 have centered on studying its potential detrimental impact on the course of the COVID-19 infection, in particular on the development of the most severe inflammatory complications. This is a logical concern as it is becoming clear that complications of COVID-19 such as severe respiratory distress syndrome are related to interferon signaling, which is the pathway that leads to expression of the PD1 ligand PD-L1. Therefore, PD1/PD-L1 ICB could potentially increase inflammatory processes, worsening the disease course for patients. However, review of the current evidence does not support the notion that ICB therapy worsens complications from COVID-19, and we conclude that it supports the continued use of ICB therapy during the COVID-19 pandemic provided that we now collect data on the effects of such therapy on COVID-19 vaccination.


Subject(s)
COVID-19/complications , COVID-19/therapy , Immune Checkpoint Inhibitors/therapeutic use , Neoplasms/therapy , B7-H1 Antigen/metabolism , Biomedical Research/economics , Biomedical Research/legislation & jurisprudence , COVID-19/immunology , COVID-19 Vaccines , Humans , Inflammation , Neoplasms/complications , Neoplasms/immunology , Pandemics , Prognosis , Programmed Cell Death 1 Receptor/metabolism , Signal Transduction
7.
J Immunother Cancer ; 8(2)2020 12.
Article in English | MEDLINE | ID: covidwho-971586

ABSTRACT

The COVID-19 outbreak caused by SARS-CoV-2 challenges the medical system by interfering with routine therapies for many patients with chronic diseases. In patients with cancer receiving immune checkpoint inhibitors (ICIs), difficulties also arise from the incomplete understanding of the intricate interplay between their routine treatment and pathogenesis of the novel virus. By referring to previous ICI-based investigations, we speculate that ICIs themselves are not linked to high-infection risks of respiratory diseases or inflammation-related adverse effects in patients with cancer. Moreover, ICI treatment may even enhance coronavirus clearance in some patients with malignant tumor by boosting antiviral T-cell responsiveness. However, the 'explosive' inflammation during COVID-19 in some ICI-treated patients with cancer was illustrated as exuberant immunopathological damage or even death. In case of the COVID-19 immunopathogenesis fueled by ICIs, we propose a regular monitor of pathogenic T-cell subsets and their exhaustion marker expression (eg, Th17 and interleukin (IL)-6-producing Th1 subsets with surface programmed death 1 expression) to guide the usage of ICI. Here we aimed to address these considerations, based on available literature and experience from our practice, that may assist with the decision-making of ICI administration during the pandemic.


Subject(s)
Antineoplastic Agents, Immunological/pharmacology , COVID-19/immunology , Cytokine Release Syndrome/prevention & control , Neoplasms/drug therapy , SARS-CoV-2/immunology , Antineoplastic Agents, Immunological/therapeutic use , COVID-19/complications , COVID-19/diagnosis , COVID-19/epidemiology , Clinical Decision-Making , Cytokine Release Syndrome/blood , Cytokine Release Syndrome/immunology , Drug Monitoring , Humans , Lung/diagnostic imaging , Neoplasms/blood , Neoplasms/immunology , Pandemics , Patient Selection , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/isolation & purification , Th1 Cells/drug effects , Th1 Cells/immunology , Th1 Cells/metabolism , Th17 Cells/drug effects , Th17 Cells/immunology , Th17 Cells/metabolism , Tomography, X-Ray Computed
8.
APMIS ; 129(2): 91-102, 2021 Feb.
Article in English | MEDLINE | ID: covidwho-900954

ABSTRACT

T cells play vital roles in the development and progression of acute coronary syndromes (ACS), including cytotoxicity mediated by CD8+ T cells and immunoregulatory activity mediated by CD4+ T cells. Interleukin (IL)-9-secreting CD4+ T cells (Th9 cells) were recently found to be involved in the onset of ACS. We investigated regulatory role of Th9 cells to CD8+ T cells in patients with stable angina pectoris, unstable angina pectoris, and acute myocardial infarction (AMI). Circulating Th9 cells percentage, plasma IL-9 level, and PU.1 mRNA relative level was up-regulated in AMI patients compared with controls. There was no significant difference of IL-9-secreting CD8+ T cells percentage among groups. CD8+ T cells from AMI patients revealed increased cytotoxicity than those from controls, which presented as enhanced cytotolytic activity to target cells, increased interferon-γ and tumor necrosis factor-α secretion, elevated perforin and granzyme B production, and reduced programmed death-1 and cytotoxic T lymphocyte-associated protein 4. IL-9 stimulation did not affect proliferation, but promoted CD8+ T-cell cytotoxicity from both controls and AMI patients. IL-9-secreting CD4+ T cells were enriched in CD4+ CCR4- CCR6- CXCR3- cells. The enhancement of CD8+ T-cell cytotoxicity induced by CD4+ CCR4- CCR6- CXCR3- cells was dependent on IL-9 secretion. The present results indicated that up-regulation of IL-9-secreting CD4+ T cells may contribute to pathogenesis of AMI through enhancement of CD8+ T-cell cytotoxicity.


Subject(s)
Acute Coronary Syndrome/pathology , CD4-Positive T-Lymphocytes/immunology , Interleukin-9/blood , T-Lymphocytes, Cytotoxic/immunology , Acute Coronary Syndrome/immunology , CTLA-4 Antigen/metabolism , Cells, Cultured , Female , Granzymes/metabolism , Humans , Interleukin-9/metabolism , Male , Middle Aged , Programmed Cell Death 1 Receptor/metabolism
9.
EMBO Mol Med ; 12(12): e13001, 2020 12 07.
Article in English | MEDLINE | ID: covidwho-881540

ABSTRACT

In patients infected by SARS-CoV-2 who experience an exaggerated inflammation leading to pneumonia, monocytes likely play a major role but have received poor attention. Thus, we analyzed peripheral blood monocytes from patients with COVID-19 pneumonia and found that these cells show signs of altered bioenergetics and mitochondrial dysfunction, had a reduced basal and maximal respiration, reduced spare respiratory capacity, and decreased proton leak. Basal extracellular acidification rate was also diminished, suggesting reduced capability to perform aerobic glycolysis. Although COVID-19 monocytes had a reduced ability to perform oxidative burst, they were still capable of producing TNF and IFN-γ in vitro. A significantly high amount of monocytes had depolarized mitochondria and abnormal mitochondrial ultrastructure. A redistribution of monocyte subsets, with a significant expansion of intermediate/pro-inflammatory cells, and high amounts of immature monocytes were found, along with a concomitant compression of classical monocytes, and an increased expression of inhibitory checkpoints like PD-1/PD-L1. High plasma levels of several inflammatory cytokines and chemokines, including GM-CSF, IL-18, CCL2, CXCL10, and osteopontin, finally confirm the importance of monocytes in COVID-19 immunopathogenesis.


Subject(s)
COVID-19/pathology , Energy Metabolism/physiology , Mitochondria/metabolism , Monocytes/metabolism , Adult , Aged , Aged, 80 and over , COVID-19/virology , Case-Control Studies , Chemokines/blood , Cytokines/blood , Female , Humans , Male , Middle Aged , Mitochondria/ultrastructure , Monocytes/cytology , Programmed Cell Death 1 Receptor/genetics , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/isolation & purification
10.
J Cell Mol Med ; 24(21): 12457-12463, 2020 11.
Article in English | MEDLINE | ID: covidwho-796054

ABSTRACT

Coronavirus disease-2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2) has rapidly spread worldwide, threatening the health and lives of many people. Unfortunately, information regarding the immunological characteristics of COVID-19 patients remains limited. Herein, we collected blood samples from 18 healthy donors (HDs) and 38 COVID-19 patients to analyse changes in the adaptive immune cell populations and their phenotypes. We observed that the lymphocyte percentage moderately decreased, CD4 and CD8 T cell percentage among lymphocytes were similar, and B cell percentage was increased in COVID-19 patients in comparison to that in HDs. T cells, especially CD8 T cells, showed an enhanced expression of late activation marker CD25 and exhaustion marker PD-1. Importantly, SARS-CoV-2 infection increased the percentage of T follicular helper- and germinal centre B-like cells in the blood. The parameters in COVID-19 patients remained unchanged across various age groups. Therefore, we demonstrated that the T and B cells are activated naturally and are functional during SARS-CoV-2 infection. These data provide evidence that the adaptive immunity in most patients could be primed to induce a significant immune response against SARS-CoV-2 infection upon receiving standard medical care.


Subject(s)
Adaptive Immunity , COVID-19/immunology , Adult , Antigens, CD/metabolism , B-Lymphocytes/virology , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/virology , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/virology , COVID-19/blood , Female , Humans , Immunophenotyping , Male , Programmed Cell Death 1 Receptor/metabolism , Receptors, CXCR5/metabolism
11.
Front Immunol ; 11: 1870, 2020.
Article in English | MEDLINE | ID: covidwho-776203

ABSTRACT

Coronavirus disease 2019 (COVID-19) which is caused by the novel SARS-CoV-2 virus is a severe flu-like illness which is associated with hyperinflammation and immune dysfunction. The virus induces a strong T and B cell response but little is known about the immune pathology of this viral infection. Acute Plasmodium falciparum malaria also causes acute clinical illness and is characterized by hyperinflammation due to the strong production of pro-inflammatory cytokines and a massive activation of T cells. In malaria, T cells express a variety of co-inhibitory receptors which might be a consequence of their activation but also might limit their overwhelming function. Thus, T cells are implicated in protection as well as in pathology. The outcome of malaria is thought to be a consequence of the balance between co-activation and co-inhibition of T cells. Following the hypothesis that T cells in COVID-19 might have a similar, dual function, we comprehensively characterized the differentiation (CCR7, CD45RO) and activation status (HLA-DR, CD38, CD69, CD226), the co-expression of co-inhibitory molecules (PD1, TIM-3, LAG-3, BTLA, TIGIT), as well as the expression pattern of the transcription factors T-bet and eomes of CD8+ and CD4+ T cells of PBMC of n = 20 SARS-CoV-2 patients compared to n = 10 P. falciparum infected patients and n = 13 healthy controls. Overall, acute COVID-19 and malaria infection resulted in a comparably elevated activation and altered differentiation status of the CD8+ and CD4+ T cell populations. T effector cells of COVID-19 and malaria patients showed higher frequencies of the inhibitory receptors T-cell immunoglobulin mucin-3 (TIM-3) and Lymphocyte-activation gene-3 (LAG-3) which was linked to increased activation levels and an upregulation of the transcription factors T-bet and eomes. COVID-19 patients with a more severe disease course showed higher levels of LAG-3 and TIM-3 than patients with a mild disease course. During recovery, a rapid normalization of these inhibitory receptors could be observed. In summary, comparing the expression of different co-inhibitory molecules in CD8+ and CD4+ T cells in COVID-19 vs. malaria, there is a transient increase of the expression of certain inhibitory receptors like LAG-3 and TIM-3 in COVID-19 in the overall context of acute immune activation.


Subject(s)
Antigens, CD/metabolism , Betacoronavirus/genetics , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Coronavirus Infections/immunology , Hepatitis A Virus Cellular Receptor 2/metabolism , Lymphocyte Activation/immunology , Malaria, Falciparum/immunology , Plasmodium falciparum/isolation & purification , Pneumonia, Viral/immunology , Receptors, Antigen, T-Cell/metabolism , Acute Disease , Adult , Aged , COVID-19 , Cells, Cultured , Cohort Studies , Coronavirus Infections/virology , Female , Humans , Malaria, Falciparum/parasitology , Male , Middle Aged , Pandemics , Pneumonia, Viral/virology , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2 , Severity of Illness Index
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