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1.
Front Immunol ; 12: 728936, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34484239

RESUMO

The use of minimal peptide sets offers an appealing alternative for design of vaccines and T cell diagnostics compared to conventional whole protein approaches. T cell immunogenicity towards peptides is contingent on binding to human leukocyte antigen (HLA) molecules of the given individual. HLA is highly polymorphic, and each variant typically presents a different repertoire of peptides. This polymorphism combined with pathogen diversity challenges the rational selection of peptide sets with broad immunogenic potential and population coverage. Here we propose PopCover-2.0, a simple yet highly effective method, for resolving this challenge. The method takes as input a set of (predicted) CD8 and/or CD4 T cell epitopes with associated HLA restriction and pathogen strain annotation together with information on HLA allele frequencies, and identifies peptide sets with optimal pathogen and HLA (class I and II) coverage. PopCover-2.0 was benchmarked on historic data in the context of HIV and SARS-CoV-2. Further, the immunogenicity of the selected SARS-CoV-2 peptides was confirmed by experimentally validating the peptide pools for T cell responses in a panel of SARS-CoV-2 infected individuals. In summary, PopCover-2.0 is an effective method for rational selection of peptide subsets with broad HLA and pathogen coverage. The tool is available at https://services.healthtech.dtu.dk/service.php?PopCover-2.0.


Assuntos
Epitopos de Linfócito T/imunologia , Antígenos HLA/genética , Antígenos HLA/imunologia , Peptídeos/imunologia , Alelos , Alergia e Imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , Genótipo , Antígenos HLA/classificação , Humanos , Imunogenicidade da Vacina , Técnicas Imunológicas , Peptídeos/classificação , SARS-CoV-2/imunologia
2.
J Immunol ; 207(5): 1388-1400, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34380649

RESUMO

Acute viral infection generates lineage-committed Th1 and T follicular helper (Tfh) memory cells that recall their lineage-specific functions following secondary challenge with virus. However, the lineage commitment of effector and memory Th cells in vivo following protein vaccination is poorly understood. In this study, we analyzed effector and memory CD4+ T cell differentiation in mice (Mus musculus) following adjuvanted glycoprotein immunization compared with acute lymphocytic choriomeningitis virus infection. Glycoprotein immunization induced CXCR5- non-Tfh effector and memory CD4+ T cells that surprisingly had not undergone polarization toward any particular Th cell lineage but had undergone memory differentiation. However, upon challenge with virus, these Th lineage-nonpolarized memory CD4+ T cells were able to generate Th1 secondary effector cells, demonstrating their lineage plasticity. In addition, Tfh and memory Tfh cells were generated in response to protein immunization, and these cells differed from infection-induced Tfh cells by their lack of the transcription factor Tbet. Rechallenge experiments demonstrated that viral infection, but not protein immunization, during either the primary or secondary immune response, restricts the recall of Bcl6 expression and the generation of germinal center Tfh cells. Together, these data demonstrate that protein immunization generates a combination of nonpolarized memory cells that are highly plastic and memory Tfh cells that can undergo further Th1-like modulation during a secondary response to viral infection.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Centro Germinativo/imunologia , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/fisiologia , Subpopulações de Linfócitos T/imunologia , Animais , Diferenciação Celular , Linhagem da Célula , Plasticidade Celular , Células Cultivadas , Imunização , Memória Imunológica , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas c-bcl-6/genética , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Vacinação
3.
J Immunol ; 207(5): 1239-1249, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34389623

RESUMO

HIV-1 infection substantially increases the risk of developing tuberculosis (TB). Mechanisms such as defects in the Th1 response to Mycobacterium tuberculosis in HIV-infected persons have been widely reported. However, Th1-independent mechanisms also contribute to protection against TB. To identify a broader spectrum of defects in TB immunity during HIV infection, we examined IL-17A and IL-22 production in response to mycobacterial Ags in peripheral blood of persons with latent TB infection and HIV coinfection. Upon stimulating with mycobacterial Ags, we observed a distinct CD4+ Th lineage producing IL-22 in the absence of IL-17A and IFN-γ. Mycobacteria-specific Th22 cells were present at high frequencies in blood and contributed up to 50% to the CD4+ T cell response to mycobacteria, comparable in magnitude to the IFN-γ Th1 response (median 0.91% and 0.55%, respectively). Phenotypic characterization of Th22 cells revealed that their memory differentiation was similar to M. tuberculosis-specific Th1 cells (i.e., predominantly early differentiated CD45RO+CD27+ phenotype). Moreover, CCR6 and CXCR3 expression profiles of Th22 cells were similar to Th17 cells, whereas their CCR4 and CCR10 expression patterns displayed an intermediate phenotype between Th1 and Th17 cells. Strikingly, mycobacterial IL-22 responses were 3-fold lower in HIV-infected persons compared with uninfected persons, and the magnitude of responses correlated inversely with HIV viral load. These data provide important insights into mycobacteria-specific Th subsets in humans and suggest a potential role for IL-22 in protection against TB during HIV infection. Further studies are needed to fully elucidate the role of IL-22 in protective TB immunity.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/imunologia , HIV-1/fisiologia , Interleucinas/metabolismo , Tuberculose Latente/imunologia , Mycobacterium tuberculosis/fisiologia , Subpopulações de Linfócitos T/imunologia , Adulto , Células Cultivadas , Coinfecção , Feminino , Soropositividade para HIV , Humanos , Interleucina-17/metabolismo , Masculino , África do Sul , Carga Viral , Adulto Jovem
4.
Nat Commun ; 12(1): 5090, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34429421

RESUMO

CRISPR-Cas9 mediated genome editing offers unprecedented opportunities for treating human diseases. There are several reports that demonstrate pre-existing immune responses to Cas9 which may have implications for clinical development of CRISPR-Cas9 mediated gene therapy. Here we use 209 overlapping peptides that span the entire sequence of Staphylococcus aureus Cas9 (SaCas9) and human peripheral blood mononuclear cells (PBMCs) from a cohort of donors with a distribution of Major Histocompatibility Complex (MHC) alleles comparable to that in the North American (NA) population to identify the immunodominant regions of the SaCas9 protein. We also use an MHC Associated Peptide Proteomics (MAPPs) assay to identify SaCas9 peptides presented by MHC Class II (MHC-II) proteins on dendritic cells. Using these two data sets we identify 22 SaCas9 peptides that are both presented by MHC-II proteins and stimulate CD4+ T-cells.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Sistemas CRISPR-Cas , Proliferação de Células/genética , Antígenos de Histocompatibilidade Classe II/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Sequência de Aminoácidos , Proteína 9 Associada à CRISPR/genética , Citocinas , Edição de Genes , Humanos , Staphylococcus aureus/genética , Linfócitos T/imunologia
5.
Viruses ; 13(8)2021 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-34452355

RESUMO

BACKGROUND: New coronavirus SARS-CoV-2, a causative agent of the COVID-19 pandemic, has been circulating among humans since November 2019. Multiple studies have assessed the qualitative and quantitative characteristics of virus-specific immunity in COVID-19 convalescents, however, some aspects of the development of memory T-cell responses after natural SARS-CoV-2 infection remain uncovered. METHODS: In most of published studies T-cell immunity to the new coronavirus is assessed using peptides corresponding to SARS-CoV-1 or SARS-CoV-2 T-cell epitopes, or with peptide pools covering various parts of the viral proteins. Here, we determined the level of CD4+ and CD8+ memory T-cell responses in COVID-19 convalescents by stimulating PBMCs collected 1 to 6 months after recovery with sucrose gradient-purified live SARS-CoV-2. IFNγ production by the central and effector memory helper and cytotoxic T cells was assessed by intracellular cytokine staining assay and flow cytometry. RESULTS: Stimulation of PBMCs with live SARS-CoV-2 revealed IFNγ-producing T-helper effector memory cells with CD4+CD45RA-CCR7- phenotype, which persisted in circulation for up to 6 month after COVID-19. In contrast, SARS-CoV-2-specific IFNγ-secreting cytotoxic effector memory T cells were found at significant levels only shortly after the disease, but rapidly decreased over time. CONCLUSION: The stimulation of immune cells with live SARS-CoV-2 revealed a rapid decline in the pool of effector memory CD8+, but not CD4+, T cells after recovery from COVID-19. These data provide additional information on the development and persistence of cellular immune responses after natural infection, and can inform further development of T cell-based SARS-CoV-2 vaccines.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , COVID-19/imunologia , Memória Imunológica , Interferon gama/imunologia , Leucócitos Mononucleares/imunologia , SARS-CoV-2/imunologia , COVID-19/virologia , Epitopos de Linfócito T/imunologia , Humanos , Leucócitos Mononucleares/virologia , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , Linfócitos T Citotóxicos/imunologia
6.
FASEB J ; 35(9): e21755, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34383962

RESUMO

Visceral leishmaniasis (VL) is a debilitating human pathogenesis in which the body's immune functions are severely compromised. Various subsets of T cells, including Th17 cells are important regulators of immune responses observed in various pathologies. The role of Th17 cells and its correlation with immuno-regulatory cytokines are however not well understood in human VL. Herein we studied how IL-17 is associated with the progression of Leishmania donovani infection using murine model of VL. We found induction of a strong IL-17 response at the early phase of infection which progressively reduced to basal level during chronic VL. The mechanistic study of this behavior was found to be linked with the role of regulatory T cells (CD4+ CD25+ T cells) that suppresses the proliferation of the Th17 cell population. Moreover, TGF-ß and IL-35 derived from CD4+ CD25+ T cells are the key mediators for the downregulation of IL-17 during chronic VL. Thus, this study points to an antagonistic effect of Tregs and Th17 cells that can be used for designing better therapeutic and preventive strategies against leishmaniasis.


Assuntos
Interleucinas/imunologia , Leishmaniose Visceral/imunologia , Células Th17/imunologia , Fator de Crescimento Transformador beta/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/parasitologia , Células Cultivadas , Subunidade alfa de Receptor de Interleucina-2/imunologia , Leishmania donovani/parasitologia , Leishmaniose Visceral/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Células Th17/parasitologia
7.
Mol Immunol ; 138: 121-127, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34392110

RESUMO

AIMS: Coronavirus disease 2019 (COVID-19) is a novel viral infection threatening worldwide health as currently there exists no effective treatment strategy and vaccination programs are not publicly available yet. T lymphocytes play an important role in antiviral defenses. However, T cell frequency and functionality may be affected during the disease. MATERIAL AND METHODS: Total blood samples were collected from patients with mild and severe COVID-19, and the total lymphocyte number, as well as CD4+ and CD8 + T cells were assessed using flowcytometry. Besides, the expression of exhausted T cell markers was evaluated. The levels of proinflammatory cytokines were also investigated in the serum of all patients using enzyme-linked immunesorbent assay (ELISA). Finally, the obtained results were analyzed along with laboratory serological reports. RESULTS: COVID-19 patients showed lymphopenia and reduced CD4+ and CD8 + T cells, as well as high percentage of PD-1 expression by T cells, especially in severe cases. Serum secretion of TNF-α, IL-1ß, and IL-2 receptor (IL-2R) were remarkably increased in patients with severe symptoms, as compared with healthy controls. Moreover, high levels of triglyceride (TG) and low density lipoprotein cholesterol (LDL-C), were correlated with the severity of the disease. CONCLUSION: Reduced number and function of T cells were observed in COVID-19 patients, especially in severe patients. Meanwhile, the secretion of proinflammatory cytokines was increased as the disease developed. High level of serum IL-2R was also considered as a sign of lymphopenia. Additionally, hypercholesterolemia and hyperlipidemia could be important prognostic factors in determining the severity of the infection.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , COVID-19/imunologia , Linfopenia/imunologia , SARS-CoV-2/imunologia , Adulto , Idoso , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/virologia , COVID-19/metabolismo , COVID-19/virologia , LDL-Colesterol/sangue , Citocinas/sangue , Citocinas/imunologia , Citocinas/metabolismo , Progressão da Doença , Feminino , Humanos , Contagem de Linfócitos , Linfopenia/sangue , Linfopenia/virologia , Masculino , Pessoa de Meia-Idade , Prognóstico , SARS-CoV-2/fisiologia , Índice de Gravidade de Doença , Triglicerídeos/sangue
8.
J Immunol ; 207(5): 1468-1477, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34408009

RESUMO

Immuno-positron emission tomography (PET), a noninvasive imaging modality, can provide a dynamic approach for longitudinal assessment of cell populations of interest. Transformation of mAbs into single-chain variable fragment (scFv)-based PET imaging agents would allow noninvasive tracking in vivo of a wide range of possible targets. We used sortase-mediated enzymatic labeling in combination with PEGylation to develop an anti-mouse CD4 scFv-based PET imaging agent constructed from an anti-mouse CD4 mAb. This anti-CD4 scFv can monitor the in vivo distribution of CD4+ T cells by immuno-PET. We tracked CD4+ and CD8+ T cells in wild-type mice, in immunodeficient recipients reconstituted with monoclonal populations of OT-II and OT-I T cells, and in a B16 melanoma model. Anti-CD4 and -CD8 immuno-PET showed that the persistence of both CD4+ and CD8+ T cells transferred into immunodeficient mice improved when recipients were immunized with OVA in CFA. In tumor-bearing animals, infiltration of both CD4+ and CD8+ T cells increased as the tumor grew. The approach described in this study should be readily applicable to convert clinically useful Abs into the corresponding scFv PET imaging agents.


Assuntos
Antígenos CD4/imunologia , Linfócitos T CD4-Positivos/imunologia , Imunoterapia/métodos , Linfócitos do Interstício Tumoral/imunologia , Melanoma/terapia , Monitorização Imunológica/métodos , Neoplasias Cutâneas/terapia , Animais , Anticorpos Monoclonais/metabolismo , Diagnóstico por Imagem , Feminino , Memória Imunológica , Melanoma Experimental , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Tomografia por Emissão de Pósitrons , Anticorpos de Cadeia Única/metabolismo
9.
Eur J Med Res ; 26(1): 93, 2021 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-34391478

RESUMO

BACKGROUND: To investigate the value of Dickkopf-related protein 3 (DKK3) on aerobic glycolysis in pancreatic cancer cells, where DKK3-overexpression is used to determine its effects on CD4+ T cells. METHODS: The BxPC-3-DKK3 cell line was constructed, and peripheral blood mononuclear cell (PBMC) was prepared. After isolated the CD4+ T cells, the lactic acid, glucose uptake ability, cellular viability, proliferation, apoptosis, and markers were detected by PCR and western blot, and the concentrations of multiple cytokines were determined using the ELISA method. RESULTS: After co-culture with pancreatic cancer cells overexpressing DKK3, the glucose uptake markedly, proliferation enhanced and apoptosis inhibited in CD4+ T cells. The co-culture model also revealed that DKK3-overexpression promotes the activation and regulates the metabolism and function of CD4+ T cells. CONCLUSIONS: DKK3 alters the metabolic microenvironment of pancreatic cancer cells and further facilitates the function of CD4+ T cells which suggesting that DKK3 may have a therapeutic potential in pancreatic cancer.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Ativação Linfocitária , Neoplasias Pancreáticas/metabolismo , Efeito Warburg em Oncologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Apoptose , Linfócitos T CD4-Positivos/imunologia , Linhagem Celular Tumoral , Células Cultivadas , Humanos
10.
Int J Mol Sci ; 22(15)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34360781

RESUMO

To identify potential early biomarkers of treatment response and immune-related adverse events (irAE), a pilot immune monitoring study was performed in stage IV melanoma patients by flow cytometric analysis of peripheral blood mononuclear cells (PBMC). Overall, 17 patients were treated with either nivolumab or pembrolizumab alone, or with a combination of nivolumab and ipilimumab every three weeks. Of 15 patients for which complete response assessment was available, treatment responders (n = 10) as compared to non-responders (n = 5) were characterized by enhanced PD-1 expression on CD8+ T cells immediately before treatment (median ± median absolute deviation/MAD 26.7 ± 10.4% vs. 17.2 ± 5.3%). Responders showed a higher T cell responsiveness after T cell receptor ex vivo stimulation as determined by measurement of programmed cell death 1 (PD-1) expression on CD3+ T cells before the second cycle of treatment. The percentage of CD8+ effector memory (CD8+CD45RA-CD45RO+CCR7-) T cells was higher in responders compared to non-responders before and immediately after the first cycle of treatment (median ± MAD 39.2 ± 7.3% vs. 30.5 ± 4.1% and 37.7 ± 4.6 vs. 24.0 ± 6.4). Immune-related adverse events (irAE) were accompanied by a higher percentage of activated CD4+ (CD4+CD38+HLADR+) T cells before the second treatment cycle (median ± MAD 14.9 ± 3.9% vs. 5.3 ± 0.4%). In summary, PBMC immune monitoring of immune-checkpoint inhibition (ICI) treatment in melanoma appears to be a promising approach to identify early markers of treatment response and irAEs.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Inibidores de Checkpoint Imunológico/administração & dosagem , Melanoma , Nivolumabe/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados/efeitos adversos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Feminino , Citometria de Fluxo , Humanos , Inibidores de Checkpoint Imunológico/efeitos adversos , Memória Imunológica/efeitos dos fármacos , Ativação Linfocitária/efeitos dos fármacos , Masculino , Melanoma/tratamento farmacológico , Melanoma/imunologia , Melanoma/patologia , Pessoa de Meia-Idade , Proteínas de Neoplasias/imunologia , Nivolumabe/efeitos adversos , Receptor de Morte Celular Programada 1/imunologia
11.
Elife ; 102021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34350827

RESUMO

For an emerging disease like COVID-19, systems immunology tools may quickly identify and quantitatively characterize cells associated with disease progression or clinical response. With repeated sampling, immune monitoring creates a real-time portrait of the cells reacting to a novel virus before disease-specific knowledge and tools are established. However, single cell analysis tools can struggle to reveal rare cells that are under 0.1% of the population. Here, the machine learning workflow Tracking Responders EXpanding (T-REX) was created to identify changes in both rare and common cells across human immune monitoring settings. T-REX identified cells with highly similar phenotypes that localized to hotspots of significant change during rhinovirus and SARS-CoV-2 infections. Specialized MHCII tetramer reagents that mark rhinovirus-specific CD4+ cells were left out during analysis and then used to test whether T-REX identified biologically significant cells. T-REX identified rhinovirus-specific CD4+ T cells based on phenotypically homogeneous cells expanding by ≥95% following infection. T-REX successfully identified hotspots of virus-specific T cells by comparing infection (day 7) to either pre-infection (day 0) or post-infection (day 28) samples. Plotting the direction and degree of change for each individual donor provided a useful summary view and revealed patterns of immune system behavior across immune monitoring settings. For example, the magnitude and direction of change in some COVID-19 patients was comparable to blast crisis acute myeloid leukemia patients undergoing a complete response to chemotherapy. Other COVID-19 patients instead displayed an immune trajectory like that seen in rhinovirus infection or checkpoint inhibitor therapy for melanoma. The T-REX algorithm thus rapidly identifies and characterizes mechanistically significant cells and places emerging diseases into a systems immunology context for comparison to well-studied immune changes.


Assuntos
COVID-19/imunologia , Leucemia Mieloide Aguda/imunologia , Melanoma/imunologia , Infecções por Picornaviridae/imunologia , Aprendizado de Máquina não Supervisionado , Adolescente , Adulto , Algoritmos , Linfócitos T CD4-Positivos/imunologia , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Melanoma/tratamento farmacológico , Neoplasias , Rhinovirus/isolamento & purificação , SARS-CoV-2/isolamento & purificação , Adulto Jovem
12.
Front Immunol ; 12: 692729, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34421902

RESUMO

Epidemiological studies and clinical trials suggest Bacillus Calmette-Guérin (BCG) vaccine has protective effects against coronavirus disease 2019 (COVID-19). There are now over 30 clinical trials evaluating if BCG vaccination can prevent or reduce the severity of COVID-19. However, the mechanism by which BCG vaccination can induce severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cell responses is unknown. Here, we identify 8 novel BCG-derived peptides with significant sequence homology to either SARS-CoV-2 NSP3 or NSP13-derived peptides. Using an in vitro co-culture system, we show that human CD4+ and CD8+ T cells primed with a BCG-derived peptide developed enhanced reactivity to its corresponding homologous SARS-CoV-2-derived peptide. As expected, HLA differences between individuals meant that not all persons developed immunogenic responses to all 8 BCG-derived peptides. Nevertheless, all of the 20 individuals that were primed with BCG-derived peptides developed enhanced T cell reactivity to at least 7 of 8 SARS-CoV-2-derived peptides. These findings provide an in vitro mechanism that may account, in part, for the epidemiologic observation that BCG vaccination confers some protection from COVID-19.


Assuntos
Vacina BCG/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Reações Cruzadas , SARS-CoV-2/imunologia , Adulto , COVID-19/imunologia , COVID-19/prevenção & controle , Células Cultivadas , Técnicas de Cocultura , Feminino , Citometria de Fluxo , Humanos , Masculino , Análise de Sequência de Proteína , Homologia de Sequência , Vacinas de Subunidades/imunologia , Adulto Jovem
13.
Science ; 373(6552)2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34437125

RESUMO

Germinal centers (GCs) are the site of immunoglobulin somatic hypermutation and affinity maturation, processes essential to an effective antibody response. The formation of GCs has been studied in detail, but less is known about what leads to their regression and eventual termination, factors that ultimately limit the extent to which antibodies mature within a single reaction. We show that contraction of immunization-induced GCs is immediately preceded by an acute surge in GC-resident Foxp3+ T cells, attributed at least partly to up-regulation of the transcription factor Foxp3 by T follicular helper (TFH) cells. Ectopic expression of Foxp3 in TFH cells is sufficient to decrease GC size, implicating the natural up-regulation of Foxp3 by TFH cells as a potential regulator of GC lifetimes.


Assuntos
Linfócitos B/imunologia , Linfócitos T CD4-Positivos/imunologia , Fatores de Transcrição Forkhead/genética , Centro Germinativo/imunologia , Células T Auxiliares Foliculares/metabolismo , Linfócitos T Reguladores/imunologia , Animais , Linfócitos T CD4-Positivos/fisiologia , Fatores de Transcrição Forkhead/metabolismo , Genes Codificadores dos Receptores de Linfócitos T , Centro Germinativo/citologia , Imunização , Imunofenotipagem , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Análise de Célula Única , Células T Auxiliares Foliculares/imunologia , Linfócitos T Reguladores/fisiologia , Regulação para Cima
14.
Front Immunol ; 12: 669357, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34349756

RESUMO

Development of adaptive immunity after COVID-19 and after vaccination against SARS-CoV-2 is predicated on recognition of viral peptides, presented on HLA class II molecules, by CD4+ T-cells. We capitalised on extensive high-resolution HLA data on twenty five human race/ethnic populations to investigate the role of HLA polymorphism on SARS-CoV-2 immunogenicity at the population and individual level. Within populations, we identify wide inter-individual variability in predicted peptide presentation from structural, non-structural and accessory SARS-CoV-2 proteins, according to individual HLA genotype. However, we find similar potential for anti-SARS-CoV-2 cellular immunity at the population level suggesting that HLA polymorphism is unlikely to account for observed disparities in clinical outcomes after COVID-19 among different race/ethnic groups. Our findings provide important insight on the potential role of HLA polymorphism on development of protective immunity after SARS-CoV-2 infection and after vaccination and a firm basis for further experimental studies in this field.


Assuntos
COVID-19/imunologia , Antígenos de Histocompatibilidade Classe II/genética , Imunidade Celular , SARS-CoV-2/imunologia , Apresentação do Antígeno , Linfócitos T CD4-Positivos/imunologia , COVID-19/genética , Genótipo , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Peptídeos/imunologia , Polimorfismo Genético , Proteoma/imunologia , Proteínas Virais/imunologia
15.
BMC Pediatr ; 21(1): 317, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34271894

RESUMO

BACKGROUND: Biliary atresia (BA) is a severe cholangiopathy possibly resulting from virus-induced and immune-mediated injury of the biliary system. IFN-γ, secreted from CD4+ Th1 cells and CD8+ cytotoxic T cells, is a major mediator of liver pathology. Programmed death protein-1 (PD-1) signaling suppresses T cell function. However, how PD-1 modify T cell function in BA remains incompletely understood. METHODS: Frequencies of PD-1 expressing CD4+ and CD8+ T cells were analyzed in the liver and blood from BA and control subjects. Associations of PD-1+CD4+/CD8+T cell abundances with liver function indices were measured. Function of PD-1 was measured by administration of an anti-PD-1 antibody in a Rhesus Rotavirus (RRV)-induced BA model. Survival, histology, direct bilirubin, liver immune cell subsets and cytokine production were analyzed. RESULTS: PD-1 was significantly upregulated in CD4+ and CD8+ T cells in patients with BA compared with control subjects. PD-1 expression in T cells was negatively associated with IFN-γ concentration in liver (PD-1+CD4+T cells in liver vs. IFN-γ concentration, r = - 0.25, p = 0.05; PD-1+CD8+T cells in liver vs. IFN-γ concentration, r = - 0.39, p = 0.004). Blockade of PD-1 increased IFN-γ expression in CD4+ T and CD8+ T cells (RRV vs. anti-PD-1 treated RRV mice: 11.59 ± 3.43% vs. 21.26 ± 5.32% IFN-γ+ in hepatic CD4+T cells, p = 0.0003; 9.33 ± 4.03% vs. 22.55 ± 7.47% IFN-γ+ in hepatic CD8+T cells, p = 0.0001), suppressed bilirubin production (RRV vs. anti-PD-1 treated RRV mice: 285.4 ± 47.93 vs. 229.8 ± 45.86 µmol/L total bilirubin, p = 0.01) and exacerbated liver immunopathology. CONCLUSIONS: PD-1 plays a protective role in infants with BA by suppressing IFN-γ production in T cells. Increasing PD-1 signaling may serve as a therapeutic strategy for BA.


Assuntos
Linfócitos T CD8-Positivos , Interferon gama/imunologia , Receptor de Morte Celular Programada 1 , Animais , Animais Recém-Nascidos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Modelos Animais de Doenças , Humanos , Lactente , Fígado , Camundongos , Camundongos Endogâmicos BALB C
16.
Nat Commun ; 12(1): 4678, 2021 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-34326343

RESUMO

SARS-CoV-2 infection of children leads to a mild illness and the immunological differences with adults are unclear. Here, we report SARS-CoV-2 specific T cell responses in infected adults and children and find that the acute and memory CD4+ T cell responses to structural SARS-CoV-2 proteins increase with age, whereas CD8+ T cell responses increase with time post-infection. Infected children have lower CD4+ and CD8+ T cell responses to SARS-CoV-2 structural and ORF1ab proteins when compared with infected adults, comparable T cell polyfunctionality and reduced CD4+ T cell effector memory. Compared with adults, children have lower levels of antibodies to ß-coronaviruses, indicating differing baseline immunity. Total T follicular helper responses are increased, whilst monocyte numbers are reduced, indicating rapid adaptive co-ordination of the T and B cell responses and differing levels of inflammation. Therefore, reduced prior ß-coronavirus immunity and reduced T cell activation in children might drive milder COVID-19 pathogenesis.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , Fatores Etários , Idoso , Anticorpos Antivirais/imunologia , COVID-19/metabolismo , COVID-19/patologia , COVID-19/virologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Inflamação/imunologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Adulto Jovem
17.
J Immunol ; 207(4): 1065-1077, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34321229

RESUMO

CNS tuberculosis (CNSTB) is the most severe manifestation of extrapulmonary tuberculosis infection, but the mechanism of how mycobacteria cross the blood-brain barrier (BBB) is not well understood. In this study, we report a novel murine in vitro BBB model combining primary brain endothelial cells, Mycobacterium bovis bacillus Calmette-Guérin-infected dendritic cells (DCs), PBMCs, and bacterial Ag-specific CD4+ T cells. We show that mycobacterial infection limits DC mobility and also induces cellular cluster formation that has a similar composition to pulmonary mycobacterial granulomas. Within the clusters, infection from DCs disseminates to the recruited monocytes, promoting bacterial expansion. Mycobacterium-induced in vitro granulomas have been described previously, but this report shows that they can form on brain endothelial cell monolayers. Cellular cluster formation leads to cluster-associated damage of the endothelial cell monolayer defined by mitochondrial stress, disorganization of the tight junction proteins ZO-1 and claudin-5, upregulation of the adhesion molecules VCAM-1 and ICAM-1, and increased transmigration of bacteria-infected cells across the BBB. TNF-α inhibition reduces cluster formation on brain endothelial cells and mitigates cluster-associated damage. These data describe a model of bacterial dissemination across the BBB shedding light on a mechanism that might contribute to CNS tuberculosis infection and facilitate treatments.


Assuntos
Barreira Hematoencefálica/imunologia , Células Dendríticas/imunologia , Mycobacterium bovis/imunologia , Tuberculose/imunologia , Fator de Necrose Tumoral alfa/imunologia , Animais , Encéfalo/imunologia , Linfócitos T CD4-Positivos/imunologia , Células Endoteliais/imunologia , Granuloma/imunologia , Molécula 1 de Adesão Intercelular/imunologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Molécula 1 de Adesão de Célula Vascular/imunologia
18.
Front Immunol ; 12: 606056, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34220792

RESUMO

Context: Immune-related adverse events frequently take place after initiation of immune checkpoint inhibitors (ICI) therapy. The thyroid gland is the endocrine organ most commonly affected by ICI therapy, the pathological mechanism is still poorly understood. Case Description: A 60-year old Upper Austrian male melanoma patient under pembrolizumab therapy received thyroidectomy because of a suspicious FDG avid thyroid nodule. Histopathology showed a pattern comparable with thyroiditis de Quervain. The inflammatory process consisted predominantly of T lymphocytes with a dominance of CD4+ T helper cells. In addition CD68+ histiocytes co-expressing PD-L1 were observed. Conclusion: Clusters of perifollicular histiocytes expressing PD-L1 were observed in this case of pembrolizumab induced thyroiditis - probably induced by the former ICI therapy. This finding might indicate the initial target for the breakdown of self tolerance. In context with other data the immunological process seems to be driven by CD3+ lymphocytes infiltrating the thyroid.


Assuntos
Anticorpos Monoclonais Humanizados/efeitos adversos , Antígeno B7-H1/metabolismo , Linfócitos T CD4-Positivos/imunologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/diagnóstico , Histiócitos/imunologia , Inibidores de Checkpoint Imunológico/efeitos adversos , Imunoterapia/métodos , Melanoma/tratamento farmacológico , Neoplasias Cutâneas/tratamento farmacológico , Glândula Tireoide/patologia , Tireoidite/diagnóstico , Anticorpos Monoclonais Humanizados/uso terapêutico , Movimento Celular , Humanos , Inibidores de Checkpoint Imunológico/uso terapêutico , Masculino , Melanoma/complicações , Melanoma/diagnóstico , Pessoa de Meia-Idade , Metástase Neoplásica , Estadiamento de Neoplasias , Neoplasias Cutâneas/complicações , Neoplasias Cutâneas/diagnóstico , Glândula Tireoide/imunologia , Tireoidectomia , Tireoidite/etiologia
19.
mBio ; 12(4): e0150321, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34311582

RESUMO

Severe coronavirus disease 2019 (COVID-19) has been associated with T cell lymphopenia, but no causal effect of T cell deficiency on disease severity has been established. To investigate the specific role of T cells in recovery from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, we studied rhesus macaques that were depleted of either CD4+, CD8+, or both T cell subsets prior to infection. Peak virus loads were similar in all groups, but the resolution of virus in the T cell-depleted animals was slightly delayed compared to that in controls. The T cell-depleted groups developed virus-neutralizing antibody responses and class switched to IgG. When reinfected 6 weeks later, the T cell-depleted animals showed anamnestic immune responses characterized by rapid induction of high-titer virus-neutralizing antibodies, faster control of virus loads, and reduced clinical signs. These results indicate that while T cells play a role in the recovery of rhesus macaques from acute SARS-CoV-2 infections, their depletion does not induce severe disease, and T cells do not account for the natural resistance of rhesus macaques to severe COVID-19. Neither primed CD4+ nor CD8+ T cells appeared critical for immunoglobulin class switching, the development of immunological memory, or protection from a second infection. IMPORTANCE Patients with severe COVID-19 often have decreased numbers of T cells, a cell type important in fighting most viral infections. However, it is not known whether the loss of T cells contributes to severe COVID-19 or is a consequence of it. We studied rhesus macaques, which develop only mild COVID-19, similar to most humans. Experimental depletion of T cells slightly prolonged their clearance of virus, but there was no increase in disease severity. Furthermore, they were able to develop protection from a second infection and produced antibodies capable of neutralizing the virus. They also developed immunological memory, which allows a much stronger and more rapid response upon a second infection. These results suggest that T cells are not critical for recovery from acute SARS-CoV-2 infections in this model and point toward B cell responses and antibodies as the essential mediators of protection from re-exposure.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/patologia , Memória Imunológica/imunologia , Linfopenia/imunologia , SARS-CoV-2/imunologia , Animais , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , COVID-19/imunologia , Feminino , Depleção Linfocítica/métodos , Macaca mulatta/imunologia , Masculino
20.
Nature ; 597(7875): 268-273, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34320609

RESUMO

SARS-CoV-2 spike mRNA vaccines1-3 mediate protection from severe disease as early as ten days after prime vaccination3, when neutralizing antibodies are hardly detectable4-6. Vaccine-induced CD8+ T cells may therefore be the main mediators of protection at this early stage7,8. The details of their induction, comparison to natural infection, and association with other arms of vaccine-induced immunity remain, however, incompletely understood. Here we show on a single-epitope level that a stable and fully functional CD8+ T cell response is vigorously mobilized one week after prime vaccination with bnt162b2, when circulating CD4+ T cells and neutralizing antibodies are still weakly detectable. Boost vaccination induced a robust expansion that generated highly differentiated effector CD8+ T cells; however, neither the functional capacity nor the memory precursor T cell pool was affected. Compared with natural infection, vaccine-induced early memory T cells exhibited similar functional capacities but a different subset distribution. Our results indicate that CD8+ T cells are important effector cells, are expanded in the early protection window after prime vaccination, precede maturation of other effector arms of vaccine-induced immunity and are stably maintained after boost vaccination.


Assuntos
Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Vacinas contra COVID-19/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Vacinação , Vacinas Sintéticas/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Linfócitos T CD4-Positivos/imunologia , COVID-19/virologia , Células Cultivadas , Epitopos de Linfócito T/imunologia , Humanos , Imunização Secundária , Memória Imunológica/imunologia , SARS-CoV-2/química , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Fatores de Tempo
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