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1.
J Exp Med ; 219(2)2022 02 07.
Article in English | MEDLINE | ID: covidwho-1594167

ABSTRACT

In rare instances, pediatric SARS-CoV-2 infection results in a novel immunodysregulation syndrome termed multisystem inflammatory syndrome in children (MIS-C). We compared MIS-C immunopathology with severe COVID-19 in adults. MIS-C does not result in pneumocyte damage but is associated with vascular endotheliitis and gastrointestinal epithelial injury. In MIS-C, the cytokine release syndrome is characterized by IFNγ and not type I interferon. Persistence of patrolling monocytes differentiates MIS-C from severe COVID-19, which is dominated by HLA-DRlo classical monocytes. IFNγ levels correlate with granzyme B production in CD16+ NK cells and TIM3 expression on CD38+/HLA-DR+ T cells. Single-cell TCR profiling reveals a skewed TCRß repertoire enriched for TRBV11-2 and a superantigenic signature in TIM3+/CD38+/HLA-DR+ T cells. Using NicheNet, we confirm IFNγ as a central cytokine in the communication between TIM3+/CD38+/HLA-DR+ T cells, CD16+ NK cells, and patrolling monocytes. Normalization of IFNγ, loss of TIM3, quiescence of CD16+ NK cells, and contraction of patrolling monocytes upon clinical resolution highlight their potential role in MIS-C immunopathogenesis.


Subject(s)
COVID-19/complications , Hepatitis A Virus Cellular Receptor 2/metabolism , Interferon-gamma/metabolism , Killer Cells, Natural/immunology , Monocytes/metabolism , Receptors, IgG/metabolism , Systemic Inflammatory Response Syndrome/immunology , T-Lymphocytes/immunology , Adolescent , Alveolar Epithelial Cells/pathology , B-Lymphocytes/immunology , Blood Vessels/pathology , COVID-19/immunology , COVID-19/pathology , Cell Proliferation , Child , Cohort Studies , Complement Activation , Cytokines/metabolism , Enterocytes/pathology , Female , Humans , Immunity, Humoral , Inflammation/pathology , Interferon Type I/metabolism , Interleukin-15/metabolism , Lymphocyte Activation/immunology , Male , Receptors, Antigen, T-Cell/metabolism , SARS-CoV-2/immunology , Superantigens/metabolism , Systemic Inflammatory Response Syndrome/pathology
2.
Front Immunol ; 12: 748097, 2021.
Article in English | MEDLINE | ID: covidwho-1477829

ABSTRACT

The SARS-CoV-2 infection [coronavirus disease 2019 (COVID-19)] is associated with severe lymphopenia and impaired immune response, including expansion of myeloid cells with regulatory functions, e.g., so-called low-density neutrophils, containing granulocytic myeloid-derived suppressor cells (LDNs/PMN-MDSCs). These cells have been described in both infections and cancer and are known for their immunosuppressive activity. In the case of COVID-19, long-term complications have been frequently observed (long-COVID). In this context, we aimed to investigate the immune response of COVID-19 convalescents after a mild or asymptomatic course of disease. We enrolled 13 convalescents who underwent a mild or asymptomatic infection with SARS-CoV-2, confirmed by a positive result of the PCR test, and 13 healthy donors without SARS-CoV-2 infection in the past. Whole blood was used for T-cell subpopulation and LDNs/PMN-MDSCs analysis. LDNs/PMN-MDSCs and normal density neutrophils (NDNs) were sorted out by FACS and used for T-cell proliferation assay with autologous T cells activated with anti-CD3 mAb. Serum samples were used for the detection of anti-SARS-CoV-2 neutralizing IgG and GM-CSF concentration. Our results showed that in convalescents, even 3 months after infection, an elevated level of LDNs/PMN-MDSCs is still maintained in the blood, which correlates negatively with the level of CD8+ and double-negative T cells. Moreover, LDNs/PMN-MDSCs and NDNs showed a tendency for affecting the production of anti-SARS-CoV-2 S1 neutralizing antibodies. Surprisingly, our data showed that in addition to LDNs/PMN-MDSCs, NDNs from convalescents also inhibit proliferation of autologous T cells. Additionally, in the convalescent sera, we detected significantly higher concentrations of GM-CSF, indicating the role of emergency granulopoiesis. We conclude that in mild or asymptomatic COVID-19 convalescents, the neutrophil dysfunction, including propagation of PD-L1-positive LDNs/PMN-MDSCs and NDNs, is responsible for long-term endotype of immunosuppression.


Subject(s)
Antibodies, Neutralizing/blood , COVID-19/complications , Myeloid-Derived Suppressor Cells/immunology , Neutrophils/immunology , SARS-CoV-2/immunology , Adult , Antibodies, Viral/blood , Asymptomatic Infections , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , COVID-19/pathology , Cell Proliferation , Female , Granulocyte-Macrophage Colony-Stimulating Factor/blood , Humans , Immunocompromised Host/immunology , Immunoglobulin G/blood , Lymphocyte Activation/immunology , Male , Middle Aged
3.
Int J Mol Sci ; 22(19)2021 Oct 08.
Article in English | MEDLINE | ID: covidwho-1463712

ABSTRACT

Nanomaterials have found extensive interest in the development of novel vaccines, as adjuvants and/or carriers in vaccination platforms. Conjugation of protein antigens at the particle surface by non-covalent adsorption is the most widely used approach in licensed particulate vaccines. Hence, it is essential to understand proteins' structural integrity at the material interface in order to develop safe-by-design nanovaccines. In this study, we utilized two model proteins, the wild-type allergen Bet v 1 and its hypoallergenic fold variant (BM4), to compare SiO2 nanoparticles with Alhydrogel® as particulate systems. A set of biophysical and functional assays including circular dichroism spectroscopy and proteolytic degradation was used to examine the antigens' structural integrity at the material interface. Conjugation of both biomolecules to the particulate systems decreased their proteolytic stability. However, we observed qualitative and quantitative differences in antigen processing concomitant with differences in their fold stability. These changes further led to an alteration in IgE epitope recognition. Here, we propose a toolbox of biophysical and functional in vitro assays for the suitability assessment of nanomaterials in the early stages of vaccine development. These tools will aid in safe-by-design innovations and allow fine-tuning the properties of nanoparticle candidates to shape a specific immune response.


Subject(s)
Allergens/immunology , Antigens, Plant/immunology , Epitopes/immunology , Lymphocyte Activation/immunology , Nanoparticles/chemistry , Silicon Dioxide/chemistry , Vaccines/immunology , Allergens/chemistry , Humans , Hydrogels , Immunoglobulin E/immunology , Respiratory Hypersensitivity/immunology , T-Lymphocytes/immunology
4.
Front Immunol ; 12: 731100, 2021.
Article in English | MEDLINE | ID: covidwho-1450811

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a serious infectious disease that has led to a global pandemic with high morbidity and mortality. High-affinity neutralizing antibody is important for controlling infection, which is closely regulated by follicular helper T (Tfh) cells. Tfh cells play a central role in promoting germinal center reactions and driving cognate B cell differentiation for antibody secretion. Available studies indicate a close relationship between virus-specific Tfh cell-mediated immunity and SARS-CoV-2 infection progression. Although several lines of evidence have suggested that Tfh cells contribute to the control of SARS-CoV-2 infection by eliciting neutralizing antibody productions, further studies are needed to elucidate Tfh-mediated effector mechanisms in anti-SARS-CoV-2 immunity. Here, we summarize the functional features and roles of virus-specific Tfh cells in the immunopathogenesis of SARS-CoV-2 infection and in COVID-19 vaccines, and highlight the potential of targeting Tfh cells as therapeutic strategy against SARS-CoV-2 infection.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , T Follicular Helper Cells/immunology , Antibody Formation/immunology , B-Lymphocytes/immunology , COVID-19/pathology , COVID-19 Vaccines/immunology , Cell Differentiation/immunology , Germinal Center/cytology , Germinal Center/immunology , Humans , Lymphocyte Activation/immunology , T Follicular Helper Cells/cytology
5.
Front Immunol ; 12: 693269, 2021.
Article in English | MEDLINE | ID: covidwho-1389185

ABSTRACT

Chronic immune activation has been considered as the driving force for CD4+ T cell depletion in people infected with HIV-1. Interestingly, the normal immune profile of adult HIV-negative individuals living in Africa also exhibit chronic immune activation, reminiscent of that observed in HIV-1 infected individuals. It is characterized by increased levels of soluble immune activation markers, such as the cytokines interleukin (IL)-4, IL-10, TNF-α, and cellular activation markers including HLA-DR, CD-38, CCR5, coupled with reduced naïve and increased memory cells in CD4+ and CD8+ subsets. In addition, it is accompanied by low CD4+ T cell counts when compared to Europeans. There is also evidence that mononuclear cells from African infants secrete less innate cytokines than South and North Americans and Europeans in vitro. Chronic immune activation in Africans is linked to environmental factors such as parasitic infections and could be responsible for previously observed immune hypo-responsiveness to infections and vaccines. It is unclear whether the immunogenicity and effectiveness of anti-SARS-CoV-2 vaccines will also be reduced by similar mechanisms. A review of studies investigating this phenomenon is urgently required as they should inform the design and delivery for vaccines to be used in African populations.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , COVID-19 Vaccines/immunology , Immunogenicity, Vaccine/immunology , Lymphocyte Activation/immunology , SARS-CoV-2/immunology , ADP-ribosyl Cyclase 1/blood , Africa , CD4 Lymphocyte Count , CD8-Positive T-Lymphocytes/immunology , COVID-19/prevention & control , HLA-DR Antigens/blood , Humans , Interleukin-10/blood , Interleukin-4/blood , Leukocytes, Mononuclear/metabolism , Membrane Glycoproteins/blood , Receptors, CCR5/blood , Tumor Necrosis Factor-alpha/blood
6.
Front Immunol ; 12: 672523, 2021.
Article in English | MEDLINE | ID: covidwho-1389182

ABSTRACT

Lower respiratory infections are among the leading causes of morbidity and mortality worldwide. These potentially deadly infections are further exacerbated due to the growing incidence of antimicrobial resistance. To combat these infections there is a need to better understand immune mechanisms that promote microbial clearance. This need in the context of lung infections has been further heightened with the emergence of SARS-CoV-2. Group 3 innate lymphoid cells (ILC3s) are a recently discovered tissue resident innate immune cell found at mucosal sites that respond rapidly in the event of an infection. ILC3s have clear roles in regulating mucosal immunity and tissue homeostasis in the intestine, though the immunological functions in lungs remain unclear. It has been demonstrated in both viral and bacterial pneumonia that stimulated ILC3s secrete the cytokines IL-17 and IL-22 to promote both microbial clearance as well as tissue repair. In this review, we will evaluate regulation of ILC3s during inflammation and discuss recent studies that examine ILC3 function in the context of both bacterial and viral pulmonary infections.


Subject(s)
COVID-19/immunology , Immunity, Mucosal/immunology , Lymphocytes/immunology , Pneumonia, Bacterial/immunology , Respiratory Mucosa/immunology , SARS-CoV-2/immunology , Bacteria/immunology , COVID-19/mortality , COVID-19/pathology , Immunity, Innate/immunology , Inflammation/immunology , Interleukin-17/metabolism , Interleukins/metabolism , Lung/immunology , Lymphocyte Activation/immunology , Respiratory Mucosa/cytology
7.
Eur J Immunol ; 51(11): 2651-2664, 2021 11.
Article in English | MEDLINE | ID: covidwho-1366229

ABSTRACT

Both B cells and T cells are involved in an effective immune response to SARS-CoV-2, the disease-causing virus of COVID-19. While B cells-with the indispensable help of CD4+ T cells-are essential to generate neutralizing antibodies, T cells on their own have been recognized as another major player in effective anti-SARS-CoV-2 immunity. In this report, we provide insights into the characteristics of individual HLA-A*02:01- and HLA-A*24:02-restricted SARS-CoV-2-reactive TCRs, isolated from convalescent COVID-19 patients. We observed that SARS-CoV-2-reactive T-cell populations were clearly detectable in convalescent samples and that TCRs isolated from these T cell clones were highly functional upon ectopic re-expression. The SARS-CoV-2-reactive TCRs described in this report mediated potent TCR signaling in reporter assays with low nanomolar EC50 values. We further demonstrate that these SARS-CoV-2-reactive TCRs conferred powerful T-cell effector function to primary CD8+ T cells as evident by a robust anti-SARS-CoV-2 IFN-γ response and in vitro cytotoxicity. We also provide an example of a long-lasting anti-SARS-CoV-2 memory response by reisolation of one of the retrieved TCRs 5 months after initial sampling. Taken together, these findings contribute to a better understanding of anti-SARS-CoV-2 T-cell immunity and may contribute to paving the way toward immunotherapeutics approaches targeting SARS-CoV-2.


Subject(s)
COVID-19/immunology , Epitopes, T-Lymphocyte/immunology , Receptors, Antigen, T-Cell/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Humans , Immunologic Memory , Lymphocyte Activation/immunology
8.
Sci Adv ; 7(34)2021 08.
Article in English | MEDLINE | ID: covidwho-1365116

ABSTRACT

The COVID-19 pandemic has spread worldwide, yet the role of antiviral T cell immunity during infection and the contribution of immune checkpoints remain unclear. By prospectively following a cohort of 292 patients with melanoma, half of which treated with immune checkpoint inhibitors (ICIs), we identified 15 patients with acute or convalescent COVID-19 and investigated their transcriptomic, proteomic, and cellular profiles. We found that ICI treatment was not associated with severe COVID-19 and did not alter the induction of inflammatory and type I interferon responses. In-depth phenotyping demonstrated expansion of CD8 effector memory T cells, enhanced T cell activation, and impaired plasmablast induction in ICI-treated COVID-19 patients. The evaluation of specific adaptive immunity in convalescent patients showed higher spike (S), nucleoprotein (N), and membrane (M) antigen-specific T cell responses and similar induction of spike-specific antibody responses. Our findings provide evidence that ICI during COVID-19 enhanced T cell immunity without exacerbating inflammation.


Subject(s)
COVID-19/immunology , Immune Checkpoint Inhibitors/immunology , Melanoma/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Adaptive Immunity/drug effects , Adaptive Immunity/immunology , Aged , Antibodies, Viral/immunology , CD8-Positive T-Lymphocytes/drug effects , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/virology , COVID-19/complications , COVID-19/virology , Female , Humans , Immune Checkpoint Inhibitors/therapeutic use , Immunologic Memory/drug effects , Immunologic Memory/immunology , Lymphocyte Activation/drug effects , Lymphocyte Activation/immunology , Male , Melanoma/complications , Melanoma/drug therapy , Middle Aged , Prospective Studies , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , T-Lymphocytes/drug effects , T-Lymphocytes/virology
9.
Front Immunol ; 12: 697840, 2021.
Article in English | MEDLINE | ID: covidwho-1359188

ABSTRACT

Monocytes are antigen-presenting cells (APCs) that play diverse roles in promoting or regulating inflammatory responses, but their role in T cell stimulation is not well defined. In inflammatory conditions, monocytes frequently show increased expression of CD169/Siglec-1, a type-I interferon (IFN-I)-regulated protein. However, little is known about the phenotype and function of these CD169+ monocytes. Here, we have investigated the phenotype of human CD169+ monocytes in different diseases, their capacity to activate CD8+ T cells, and the potential for a targeted-vaccination approach. Using spectral flow cytometry, we detected CD169 expression by CD14+ CD16- classical and CD14+ CD16+ intermediate monocytes and unbiased analysis showed that they were distinct from dendritic cells, including the recently described CD14-expressing DC3. CD169+ monocytes expressed higher levels of co-stimulatory and HLA molecules, suggesting an increased activation state. IFNα treatment highly upregulated CD169 expression on CD14+ monocytes and boosted their capacity to cross-present antigen to CD8+ T cells. Furthermore, we observed CD169+ monocytes in virally-infected patients, including in the blood and bronchoalveolar lavage fluid of COVID-19 patients, as well as in the blood of patients with different types of cancers. Finally, we evaluated two CD169-targeting nanovaccine platforms, antibody-based and liposome-based, and we showed that CD169+ monocytes efficiently presented tumor-associated peptides gp100 and WT1 to antigen-specific CD8+ T cells. In conclusion, our data indicate that CD169+ monocytes are activated monocytes with enhanced CD8+ T cell stimulatory capacity and that they emerge as an interesting target in nanovaccine strategies, because of their presence in health and different diseases.


Subject(s)
Antigen Presentation/immunology , CD8-Positive T-Lymphocytes/immunology , Lymphocyte Activation/immunology , Monocytes/immunology , Sialic Acid Binding Ig-like Lectin 1/metabolism , COVID-19/immunology , Carcinoma, Pancreatic Ductal/immunology , Cells, Cultured , Flow Cytometry , Humans , Influenza, Human/immunology , Interferon-alpha/pharmacology , Lipopolysaccharide Receptors/metabolism , Lung Neoplasms/immunology , Pancreatic Neoplasms/immunology , SARS-CoV-2/immunology
10.
Sci Immunol ; 6(59)2021 05 25.
Article in English | MEDLINE | ID: covidwho-1337429

ABSTRACT

Multiple Inflammatory Syndrome in Children (MIS-C) is a delayed and severe complication of SARS-CoV-2 infection that strikes previously healthy children. As MIS-C combines clinical features of Kawasaki disease and Toxic Shock Syndrome (TSS), we aimed to compare the immunological profile of pediatric patients with these different conditions. We analyzed blood cytokine expression, and the T cell repertoire and phenotype in 36 MIS-C cases, which were compared to 16 KD, 58 TSS, and 42 COVID-19 cases. We observed an increase of serum inflammatory cytokines (IL-6, IL-10, IL-18, TNF-α, IFNγ, CD25s, MCP1, IL-1RA) in MIS-C, TSS and KD, contrasting with low expression of HLA-DR in monocytes. We detected a specific expansion of activated T cells expressing the Vß21.3 T cell receptor ß chain variable region in both CD4 and CD8 subsets in 75% of MIS-C patients and not in any patient with TSS, KD, or acute COVID-19; this correlated with the cytokine storm detected. The T cell repertoire returned to baseline within weeks after MIS-C resolution. Vß21.3+ T cells from MIS-C patients expressed high levels of HLA-DR, CD38 and CX3CR1 but had weak responses to SARS-CoV-2 peptides in vitro. Consistently, the T cell expansion was not associated with specific classical HLA alleles. Thus, our data suggested that MIS-C is characterized by a polyclonal Vß21.3 T cell expansion not directed against SARS-CoV-2 antigenic peptides, which is not seen in KD, TSS and acute COVID-19.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , COVID-19/pathology , Receptors, Antigen, T-Cell, alpha-beta/immunology , Systemic Inflammatory Response Syndrome/immunology , Systemic Inflammatory Response Syndrome/pathology , Adult , Child , Child, Preschool , Cytokines/blood , HLA-DR Antigens/immunology , Humans , Lymphocyte Activation/immunology , SARS-CoV-2/immunology
11.
J Immunol ; 207(4): 1099-1111, 2021 08 15.
Article in English | MEDLINE | ID: covidwho-1328168

ABSTRACT

Understanding the function of SARS-CoV-2 Ag-specific T cells is crucial for the monitoring of antiviral immunity and vaccine design. Currently, both impaired and robust T cell immunity is described in COVID-19 patients. In this study, we explored and compared the effector functions of SARS-CoV-2-reactive T cells expressing coinhibitory receptors and examine the immunogenicity of SARS-CoV-2 S, M, and N peptide pools in regard to specific effector T cell responses, Th1/Th2/Th17, in COVID-19 patients. Analyzing a cohort of 108 COVID-19 patients with mild, moderate, and severe disease, we observed that coinhibitory receptors (e.g., PD-1, CTLA-4, TIM-3, VISTA, CD39, CD160, 2B4, TIGIT, Gal-9, and NKG2A) were upregulated on both CD4+ and CD8+ T cells. Importantly, the expression of coinhibitory receptors on T cells recognizing SARS-CoV-2 peptide pools (M/N/S) was associated with increased frequencies of cytokine-producing T cells. Thus, our data refute the concept of pathological T cell exhaustion in COVID-19 patients. Despite interindividual variations in the T cell response to viral peptide pools, a Th2 phenotype was associated with asymptomatic and milder disease, whereas a robust Th17 was associated with severe disease, which may potentiate the hyperinflammatory response in patients admitted to the Intensive Care Unit. Our data demonstrate that T cells may either play a protective or detrimental role in COVID-19 patients. This finding could have important implications for immune correlates of protection, diagnostic, and prophylaxis with respect to COVID-19 management.


Subject(s)
COVID-19/immunology , SARS-CoV-2/immunology , Th17 Cells/immunology , Th2 Cells/immunology , Adult , Aged , Coronavirus Nucleocapsid Proteins/immunology , Female , Humans , Lymphocyte Activation/immunology , Male , Middle Aged , Phosphoproteins/immunology , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes/immunology , Viral Matrix Proteins/immunology
12.
Mol Immunol ; 137: 221-227, 2021 09.
Article in English | MEDLINE | ID: covidwho-1313337

ABSTRACT

Natural Killer (NK) cells are considered the first line of defense against viral infections and tumors. Several factors affect NK cytotoxic activity rendering it dysfunctional and thereby impeding the ability to scavenge abnormal cells as a part of immune escaping mechanisms induced by different types of cancers. NK cells play a crucial role augmenting the activity of various types of anticancer mAb since dysfunctional NK cells are the main reason for the low response to these therapies. To this light, we examined the phenotypic characters of the circulating NK cells isolated from HCC patients compared to healthy controls. Then, dysfunctional NK cells, from HCC patients, were reactivated with cytokines cocktail and their cytotoxic activity with the anti-EGFR mAb "cetuximab" was investigated. This showed a downregulation of patients NK cells activating receptors (NKP30, NKP46, NKG2D and CD16) as well as CD56 and up-regulation of NKG2A inhibitory receptor. We also reported an increase in aberrant CD56- NK cells subset in peripheral blood of HCC patients compared to healthy controls. Thus, confirming the dysfunctionality of peripheral NK cells isolated from HCC patients. Cytokines re-activation of those NK cells lead to upregulation of NK activating receptors and downregulation of inhibitory receptor. Moreover, the percentage of aberrant CD56- NK cells subset was reduced. Here, we proved that advanced HCC patients have an increased percentage of more immature and noncytotoxic NK cell subsets in their peripheral blood, which might account for the low cytotoxicity noticed in those patients. A significant improvement in the cytotoxicity against HCC was noticed upon using reactivated NK cells combined with cetuximab. Therefore, this study highlights the potential recruitment of NK immune cells along with cetuximab to enhance cytotoxicity against HCC.


Subject(s)
Antibody-Dependent Cell Cytotoxicity/immunology , Antineoplastic Agents, Immunological/therapeutic use , Carcinoma, Hepatocellular/therapy , Cetuximab/therapeutic use , Cytokines/pharmacology , Killer Cells, Natural/immunology , Liver Neoplasms/therapy , CD56 Antigen/metabolism , Cell Line, Tumor , Humans , Lymphocyte Activation/immunology , NK Cell Lectin-Like Receptor Subfamily C/metabolism
13.
Signal Transduct Target Ther ; 6(1): 213, 2021 05 31.
Article in English | MEDLINE | ID: covidwho-1249203

ABSTRACT

Although inoculation of COVID-19 vaccines has rolled out globally, there is still a critical need for safe and effective vaccines to ensure fair and equitable supply for all countries. Here, we report on the development of a highly efficacious mRNA vaccine, SW0123 that is composed of sequence-modified mRNA encoding the full-length SARS-CoV-2 Spike protein packaged in core-shell structured lipopolyplex (LPP) nanoparticles. SW0123 is easy to produce using a large-scale microfluidics-based apparatus. The unique core-shell structured nanoparticle facilitates vaccine uptake and demonstrates a high colloidal stability, and a desirable biodistribution pattern with low liver targeting effect upon intramuscular administration. Extensive evaluations in mice and nonhuman primates revealed strong immunogenicity of SW0123, represented by induction of Th1-polarized T cell responses and high levels of antibodies that were capable of neutralizing not only the wild-type SARS-CoV-2, but also a panel of variants including D614G and N501Y variants. In addition, SW0123 conferred effective protection in both mice and non-human primates upon SARS-CoV-2 challenge. Taken together, SW0123 is a promising vaccine candidate that holds prospects for further evaluation in humans.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/therapeutic use , Female , Humans , Immunogenicity, Vaccine/immunology , Lymphocyte Activation/immunology , Mice , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Th1 Cells/immunology , Th1 Cells/virology , Vaccines, Synthetic/immunology , Vaccines, Synthetic/therapeutic use , Viral Vaccines/immunology
14.
Nat Commun ; 12(1): 3006, 2021 05 21.
Article in English | MEDLINE | ID: covidwho-1238000

ABSTRACT

Coronavirus disease 2019 (COVID-19) can lead to pneumonia and hyperinflammation. Here we show a sensitive method to measure polyclonal T cell activation by downstream effects on responder cells like basophils, plasmacytoid dendritic cells, monocytes and neutrophils in whole blood. We report a clear T cell hyporeactivity in hospitalized COVID-19 patients that is pronounced in ventilated patients, associated with prolonged virus persistence and reversible with clinical recovery. COVID-19-induced T cell hyporeactivity is T cell extrinsic and caused by plasma components, independent of occasional immunosuppressive medication of the patients. Monocytes respond stronger in males than females and IL-2 partially restores T cell activation. Downstream markers of T cell hyporeactivity are also visible in fresh blood samples of ventilated patients. Based on our data we developed a score to predict fatal outcomes and identify patients that may benefit from strategies to overcome T cell hyporeactivity.


Subject(s)
COVID-19/immunology , Inflammation/immunology , Lymphocyte Activation/immunology , Pneumonia/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Adult , Aged , Basophils/immunology , COVID-19/virology , Cells, Cultured , Dendritic Cells/immunology , Female , Humans , Male , Middle Aged , Monocytes/immunology , Neutrophils/immunology , SARS-CoV-2/physiology , Young Adult
15.
Immunity ; 54(6): 1257-1275.e8, 2021 06 08.
Article in English | MEDLINE | ID: covidwho-1230571

ABSTRACT

The kinetics of the immune changes in COVID-19 across severity groups have not been rigorously assessed. Using immunophenotyping, RNA sequencing, and serum cytokine analysis, we analyzed serial samples from 207 SARS-CoV2-infected individuals with a range of disease severities over 12 weeks from symptom onset. An early robust bystander CD8+ T cell immune response, without systemic inflammation, characterized asymptomatic or mild disease. Hospitalized individuals had delayed bystander responses and systemic inflammation that was already evident near symptom onset, indicating that immunopathology may be inevitable in some individuals. Viral load did not correlate with this early pathological response but did correlate with subsequent disease severity. Immune recovery is complex, with profound persistent cellular abnormalities in severe disease correlating with altered inflammatory responses, with signatures associated with increased oxidative phosphorylation replacing those driven by cytokines tumor necrosis factor (TNF) and interleukin (IL)-6. These late immunometabolic and immune defects may have clinical implications.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , COVID-19/virology , Host-Pathogen Interactions/immunology , Lymphocyte Activation/immunology , SARS-CoV-2/immunology , Biomarkers , CD8-Positive T-Lymphocytes/metabolism , COVID-19/diagnosis , COVID-19/genetics , Cytokines/metabolism , Disease Susceptibility , Gene Expression Profiling , Humans , Inflammation Mediators/metabolism , Longitudinal Studies , Lymphocyte Activation/genetics , Oxidative Phosphorylation , Phenotype , Prognosis , Reactive Oxygen Species/metabolism , Severity of Illness Index , Transcriptome
16.
Eur J Immunol ; 51(8): 2074-2085, 2021 08.
Article in English | MEDLINE | ID: covidwho-1212744

ABSTRACT

The aberrant release of inflammatory mediators often referred to as a cytokine storm or cytokine release syndrome (CRS), is a common and sometimes fatal complication in acute infectious diseases including Ebola, dengue, COVID-19, and influenza. Fatal CRS occurrences have also plagued the development of highly promising cancer therapies based on T-cell engagers and chimeric antigen receptor (CAR) T cells. CRS is intimately linked with dysregulated and excessive cytokine release, including IFN-γ, TNF-α, IL 1, IL-6, and IL-10, resulting in a systemic inflammatory response leading to multiple organ failure. Here, we show that mice intravenously administered the agonistic hamster anti-mouse CD3ε monoclonal antibody 145-2C11 develop clinical and laboratory manifestations seen in patients afflicted with CRS, including body weight loss, hepatosplenomegaly, thrombocytopenia, increased vascular permeability, lung inflammation, and hypercytokinemia. Blood cytokine levels and gene expression analysis from lung, liver, and spleen demonstrated a hierarchy of inflammatory cytokine production and infiltrating immune cells with differentiating organ-dependent kinetics. IL-2, IFN-γ, TNF-α, and IL-6 up-regulation preceded clinical signs of CRS. The co-treatment of mice with a neutralizing anti-cytokine antibody cocktail transiently improved early clinical and laboratory features of CRS. We discuss the predictive use of this model in the context of new anti-cytokine strategies to treat human CRS.


Subject(s)
Antibodies, Monoclonal/pharmacology , Antibodies/immunology , CD3 Complex/antagonists & inhibitors , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/metabolism , Cytokines/antagonists & inhibitors , Cytokines/metabolism , Animals , Antibodies/adverse effects , Antibodies, Monoclonal/therapeutic use , Cytokine Release Syndrome/diagnosis , Cytokine Release Syndrome/drug therapy , Cytokines/blood , Disease Models, Animal , Drug Therapy, Combination , Inflammation Mediators/blood , Inflammation Mediators/metabolism , Lymphocyte Activation/immunology , Mice , Phenotype , Severity of Illness Index , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Treatment Outcome
17.
Int J Mol Sci ; 21(18)2020 Sep 05.
Article in English | MEDLINE | ID: covidwho-1215392

ABSTRACT

The transcription factor T cell factor 1 (TCF1), a pioneer transcription factor as well as a downstream effector of WNT/ß-catenin signaling, is indispensable for T cell development in the thymus. Recent studies have highlighted the additional critical role of TCF1 in peripheral T cell responses to acute and chronic infections as well as cancer. Here, we review the regulatory functions of TCF1 in the differentiation of T follicular helper cells, memory T cells and recently described stem-like exhausted T cells, where TCF1 promotes less differentiated stem-like cell states by controlling common gene-regulatory networks. These studies also provide insights into the mechanisms of defective T cell responses in older individuals. We discuss alterations in TCF1 expression and related regulatory networks with age and their consequences for T cell responses to infections and vaccination. The increasing understanding of the pathways regulating TCF1 expression and function in aged T cells holds the promise of enabling the design of therapeutic interventions aiming at improving T cell responses in older individuals.


Subject(s)
Cell Differentiation/physiology , T Cell Transcription Factor 1/metabolism , T-Lymphocytes/metabolism , Aging/genetics , Aging/physiology , Animals , CD8-Positive T-Lymphocytes/immunology , Cellular Senescence/genetics , Cellular Senescence/physiology , Gene Expression Regulation/genetics , Hematopoiesis/physiology , Humans , Lymphocyte Activation/immunology , T Cell Transcription Factor 1/physiology , Transcription Factors/genetics , Transcription Factors/metabolism , Wnt Signaling Pathway/physiology
19.
Front Immunol ; 12: 626308, 2021.
Article in English | MEDLINE | ID: covidwho-1190310

ABSTRACT

We have previously shown that conformational change in the ß2-integrin is a very early activation marker that can be detected with fluorescent multimers of its ligand intercellular adhesion molecule (ICAM)-1 for rapid assessment of antigen-specific CD8+ T cells. In this study, we describe a modified protocol of this assay for sensitive detection of functional antigen-specific CD4+ T cells using a monoclonal antibody (clone m24 Ab) specific for the open, high-affinity conformation of the ß2-integrin. The kinetics of ß2-integrin activation was different on CD4+ and CD8+ T cells (several hours vs. few minutes, respectively); however, m24 Ab readily stained both cell types 4-6 h after antigen stimulation. With this protocol, we were able to monitor ex vivo effector and memory CD4+ and CD8+ T cells specific for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), cytomegalovirus (CMV), Epstein-Barr virus (EBV), and hepatitis B virus (HBV) in whole blood or cryopreserved peripheral blood mononuclear cells (PBMCs) of infected or vaccinated individuals. By costaining ß2-integrin with m24 and CD154 Abs, we assessed extremely low frequencies of polyfunctional CD4+ T cell responses. The novel assay used in this study allows very sensitive and simultaneous screening of both CD4+ and CD8+ T cell reactivities, with versatile applicability in clinical and vaccination studies.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Host-Pathogen Interactions/immunology , Integrins/metabolism , Adult , Aged , Amino Acid Sequence , Binding Sites , COVID-19/genetics , COVID-19/immunology , COVID-19/metabolism , COVID-19/virology , Carrier Proteins/chemistry , Cytokines/metabolism , Cytomegalovirus/immunology , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/immunology , Female , HLA Antigens/chemistry , HLA Antigens/immunology , Host-Pathogen Interactions/genetics , Humans , Immunohistochemistry , Immunophenotyping , Integrins/genetics , Intercellular Adhesion Molecule-1/chemistry , Intercellular Adhesion Molecule-1/metabolism , Lymphocyte Activation/immunology , Male , Middle Aged , Protein Binding , Protein Multimerization , SARS-CoV-2/immunology , T-Cell Antigen Receptor Specificity , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism
20.
PLoS Pathog ; 17(4): e1009448, 2021 04.
Article in English | MEDLINE | ID: covidwho-1190180

ABSTRACT

The SARS-CoV-2 infection causes severe respiratory involvement (COVID-19) in 5-20% of patients through initial immune derangement, followed by intense cytokine production and vascular leakage. Evidence of immune involvement point to the participation of T, B, and NK cells in the lack of control of virus replication leading to COVID-19. NK cells contribute to early phases of virus control and to the regulation of adaptive responses. The precise mechanism of NK cell dysregulation is poorly understood, with little information on tissue margination or turnover. We investigated these aspects by multiparameter flow cytometry in a cohort of 28 patients hospitalized with early COVID-19. Relevant decreases in CD56brightCD16+/- NK subsets were detected, with a shift of circulating NK cells toward more mature CD56dimCD16+KIR+NKG2A+ and "memory" KIR+CD57+CD85j+ cells with increased inhibitory NKG2A and KIR molecules. Impaired cytotoxicity and IFN-γ production were associated with conserved expression of natural cytotoxicity receptors and perforin. Moreover, intense NK cell activation with increased HLA-DR and CD69 expression was associated with the circulation of CD69+CD103+ CXCR6+ tissue-resident NK cells and of CD34+DNAM-1brightCXCR4+ inflammatory precursors to mature functional NK cells. Severe disease trajectories were directly associated with the proportion of CD34+DNAM-1brightCXCR4+ precursors and inversely associated with the proportion of NKG2D+ and of CD103+ NK cells. Intense NK cell activation and trafficking to and from tissues occurs early in COVID-19, and is associated with subsequent disease progression, providing an insight into the mechanism of clinical deterioration. Strategies to positively manipulate tissue-resident NK cell responses may provide advantages to future therapeutic and vaccine approaches.


Subject(s)
COVID-19/immunology , Killer Cells, Natural/immunology , Aged , Aged, 80 and over , COVID-19/mortality , Cohort Studies , Female , Flow Cytometry/methods , Humans , Interferon-gamma/metabolism , Italy/epidemiology , Lymphocyte Activation/immunology , Male , Middle Aged , Severity of Illness Index
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