Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 81.005
Filtrar
1.
Front Immunol ; 11: 569611, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33133083

RESUMO

COVID-19 caused by SARS CoV2 emerged in China at the end of 2019 and soon become a pandemic. Since the virus is novel, pre-existing CoV2-specific immunity is not expected to exist in humans, although studies have shown presence of CoV2 cross-reactive T cells in unexposed individuals. Lack of effective immunity in most individuals along with high infectiousness of the virus has resulted in massive global public health emergency. Intense efforts are on to study viral pathogenesis and immune response to help guide prophylactic and therapeutic interventions as well as epidemiological assessments like transmission modeling. To develop an effective vaccine or biologic therapeutic, it is critical to understand the immune correlates of COVID-19 control. At the same time, whether immunity in recovered individuals is effective for preventing re-infection will be important for informing interventions like social distancing. Key questions that are being investigated regarding immune response in COVID-19 which will help these efforts include, investigations of immune response that distinguishes patients with severe versus mild infection or those that recover relative to those that succumb, durability of immunity in recovered patients and relevance of developed immunity in a cured patient for protection against re-infection as well as value of convalescent plasma from recovered patients as a potential therapeutic modality. This is a broad and rapidly evolving area and multiple reports on status of innate and adaptive immunity against SARS-CoV2 are emerging on a daily basis. While many questions remain unanswered for now, the purpose of this focused review is to summarize the current understanding regarding immune correlates of COVID-19 severity and resolution in order to assist researchers in the field to pursue new directions in prevention and control.


Assuntos
Infecções por Coronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/imunologia , Pneumonia Viral/prevenção & controle , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Infecções por Coronavirus/tratamento farmacológico , Citocinas/imunologia , Humanos , Mediadores da Inflamação/imunologia , Gravidade do Paciente , Recidiva , Linfócitos T/imunologia , Vacinas Virais/imunologia
3.
Nat Commun ; 11(1): 5435, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33116135

RESUMO

Memory B cells (MBCs) are long-lived and produce high-affinity, generally, class-switched antibodies. Here, we use a multiparameter approach involving CD27 to segregate naïve B cells (NBC), IgD+ unswitched (unsw)MBCs and IgG+ or IgA+ class-switched (sw)MBCs from humans of different age, sex and race. Conserved antibody variable gene expression indicates that MBCs emerge through unbiased selection from NBCs. Integrative analyses of mRNAs, miRNAs, lncRNAs, chromatin accessibility and cis-regulatory elements uncover a core mRNA-ncRNA transcriptional signature shared by IgG+ and IgA+ swMBCs and distinct from NBCs, while unswMBCs display a transitional transcriptome. Some swMBC transcriptional signature loci are accessible but not expressed in NBCs. Profiling miRNAs reveals downregulated MIR181, and concomitantly upregulated MIR181 target genes such as RASSF6, TOX, TRERF1, TRPV3 and RORα, in swMBCs. Finally, lncRNAs differentially expressed in swMBCs cluster proximal to the IgH chain locus on chromosome 14. Our findings thus provide new insights into MBC transcriptional programs and epigenetic regulation, opening new investigative avenues on these critical cell elements in human health and disease.


Assuntos
Linfócitos B/imunologia , Memória Imunológica/genética , Adulto , Linfócitos B/classificação , Linfócitos B/metabolismo , Cromatina/genética , Cromatina/imunologia , Regiões Determinantes de Complementaridade , Epigênese Genética , Feminino , Perfilação da Expressão Gênica , Humanos , Switching de Imunoglobulina/genética , Cadeias Pesadas de Imunoglobulinas/genética , Masculino , MicroRNAs/genética , MicroRNAs/metabolismo , Mutação Puntual , Transdução de Sinais/genética , Fatores de Transcrição/genética , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Adulto Jovem
4.
Medicine (Baltimore) ; 99(44): e22490, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33126303

RESUMO

RATIONALE: ALL is the most common form of leukemia (75% to 80%), it is characterized by clonal expansion of the lymphoid blasts in bone marrow, blood, and other tissues, which can be divided into T lineage and B lineage. Although relapse of acute leukemia is common, a change of immunophenotype at relapse only occurs rarely. Some of these cases have been labeled "lineage switch". PATIENT CONCERNS: A 31-year-old man had multiple lymph nodes in the neck, and the lymph nodes on the right side adhered to the surrounding tissues. His lymphocytes ratio in blood was up to 86.3%. Flow cytometry of the bone marrow aspirate showed positive results for CD2, CD5, CD7, cCD3, TDT, CD4, CD8, and CD10, negative results for CD34, CD117, CD33, HLA-DR, CD19, and CD20. Twenty six months later, the patient felt pain in the neck and shoulder after touching. His lymphocytes of blood were 109.9×109 /L. 43 fusion genes and positive BCR/ABL was detected. Flow cytometry of the bone marrow aspirate showed pro B lymphocytes accounted for 85.54%, and positive expression of CD38, CD10, CD34, CD33, TDT, CD9, and HLA-DR. Moreover, the RT-PCR data showed the patient expressed high level of T cell and B cell development transcription factors. DIAGNOSES: Upon examination, the patient was initially diagnosed with T-lineage pro cell ALL. BM morphologic analysis presented complete remission (CR) after systemic chemotherapy. Twenty six months later, we discovered the patient was diagnosed with B-lineage acute lymphocytic leukemia. INTERVENTIONS: Systemic chemotherapy is first given when a patient was diagnosed with T-cell acute lymphoblastic leukemia. After the patient happened linage switch, we adjusted the treatment plan, and the patient was complete remission after 1 course of treatment. OUTCOMES: Our case provides information of lineage switch from T-ALL to B-ALL in this report, which is never seen in our knowledge. LESSONS: This lineage switch from T-ALL to B-ALL is never reported beforemoreover, the RT-PCR data showed the patient expressed high level of T cell and B cell development transcription factors. Its early recognition can let doctor provides appropriate therapy to patient.


Assuntos
Leucemia Aguda Bifenotípica/sangue , Linfoma de Células B/sangue , Linfoma de Células T/sangue , Doença Aguda , Adulto , Linfócitos B , Linhagem da Célula , Humanos , Leucemia Aguda Bifenotípica/tratamento farmacológico , Linfoma de Células B/tratamento farmacológico , Linfoma de Células T/tratamento farmacológico , Masculino , Linfócitos T
6.
Front Immunol ; 11: 582010, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33117392

RESUMO

Severe COVID-19 is associated with profound lymphopenia and an elevated neutrophil to lymphocyte ratio. We applied a novel dimer avoidance multiplexed polymerase chain reaction next-generation sequencing assay to analyze T (TCR) and B cell receptor (BCR) repertoires. Surprisingly, TCR repertoires were markedly diminished during the early onset of severe disease but recovered during the convalescent stage. Monitoring TCR repertoires could serve as an indicative biomarker to predict disease progression and recovery. Panoramic concurrent assessment of BCR repertoires demonstrated isotype switching and a transient but dramatic early IgA expansion. Dominant B cell clonal expansion with decreased diversity occurred following recovery from infection. Profound changes in T cell homeostasis raise critical questions about the early events in COVID-19 infection and demonstrate that immune repertoire analysis is a promising method for evaluating emergent host immunity to SARS-CoV-2 viral infection, with great implications for assessing vaccination and other immunological therapies.


Assuntos
Linfócitos B/imunologia , Betacoronavirus/imunologia , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos T/genética , Linfócitos T/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Contagem de Linfócito CD4 , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/patologia , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Linfopenia/patologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/patologia
8.
Nat Commun ; 11(1): 5084, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-33033253

RESUMO

Identifying factors underlying resistance to immune checkpoint therapy (ICT) is still challenging. Most cancer patients do not respond to ICT and the availability of the predictive biomarkers is limited. Here, we re-analyze a publicly available single-cell RNA sequencing (scRNA-seq) dataset of melanoma samples of patients subjected to ICT and identify a subset of macrophages overexpressing TREM2 and a subset of gammadelta T cells that are both overrepresented in the non-responding tumors. In addition, the percentage of a B cell subset is significantly lower in the non-responders. The presence of these immune cell subtypes is corroborated in other publicly available scRNA-seq datasets. The analyses of bulk RNA-seq datasets of the melanoma samples identify and validate a signature - ImmuneCells.Sig - enriched with the genes characteristic of the above immune cell subsets to predict response to immunotherapy. ImmuneCells.Sig could represent a valuable tool for clinical decision making in patients receiving immunotherapy.


Assuntos
Perfilação da Expressão Gênica , Imunoterapia , Macrófagos/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Receptores Imunológicos/metabolismo , Linfócitos T/metabolismo , Área Sob a Curva , Linfócitos B/metabolismo , Biomarcadores Tumorais/metabolismo , Humanos , Macrófagos/patologia , Melanoma/genética , Melanoma/patologia , Reprodutibilidade dos Testes
9.
Clin Exp Rheumatol ; 38 Suppl 126(4): 271-282, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33025890

RESUMO

Primary Sjögren's syndrome (pSS) is often considered a B cell-mediated disease, yet the precise role of B cells in the pathogenesis is not fully understood. This is exemplified by the failure of multiple clinical trials directed at B cell depletion or inhibition. To date, most prognostic markers for severe disease outcomes are autoantibodies, but the underlying mechanisms by which B cells drive diverse disease presentations in pSS likely extend beyond autoantibody production. Here we outline an expanded role of B cells in disease pathogenesis drawing on examples from animal models of SS, and from other autoimmune diseases that share similar clinical or immunological abnormalities. We focus on recent findings from the detailed analysis of pathogenic B cells in patients with pSS to propose strategies for patient stratification to improve clinical trial outcomes. We conclude that an integrated cellular, molecular and genetic analysis of patients with pSS will reveal the underlying pathogenic mechanisms and guide precision medicine.


Assuntos
Doenças Autoimunes , Síndrome de Sjogren , Animais , Autoanticorpos , Linfócitos B , Humanos , Síndrome de Sjogren/diagnóstico
10.
Clin Exp Rheumatol ; 38 Suppl 126(4): 315-323, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33095148

RESUMO

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disorder affecting exocrine glands of the body, prevalently lacrimal and salivary glands. The pSS pathogenesis has been thought to be B-cell-centric and several clinical trials have been carried out in order to clarify the therapeutic role of B-cell depletion in patients with pSS. Unfortunately, however, B-cell depletion with rituximab has failed in demonstrating any significant results in pSS patients. Besides the contribution of B cells in the pathogenesis of pSS, effector Tfh, Th17 and Th22 cells, follicular dendritic cells (DCs), innate cells (ICs) and several cytokines, chemokines and miRNA have been proved to participate to the development of this systemic disease. Understanding these molecular processes may help guide research into resistant diseases and highly targeted therapeutic strategies. This review aims to discuss important pathogenetic mechanisms involved in the initiation and perpetuation of pSS behind the established role of B cells.


Assuntos
MicroRNAs , Síndrome de Sjogren , Linfócitos B , Humanos , Rituximab , Glândulas Salivares , Síndrome de Sjogren/tratamento farmacológico
11.
Sci Rep ; 10(1): 17718, 2020 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-33077873

RESUMO

COVID-19 has been widely spreading. We aimed to examine adaptive immune cells in non-severe patients with persistent SARS-CoV-2 shedding. 37 non-severe patients with persistent SARS-CoV-2 presence that were transferred to Zhongnan hospital of Wuhan University were retrospectively recruited to the PP (persistently positive) group, which was further allocated to PPP group (n = 19) and PPN group (n = 18), according to their testing results after 7 days (N = negative). Epidemiological, demographic, clinical and laboratory data were collected and analyzed. Data from age- and sex-matched non-severe patients at disease onset (PA [positive on admission] patients, n = 37), and lymphocyte subpopulation measurements from matched 54 healthy subjects were extracted for comparison (HC). Compared with PA patients, PP patients had much improved laboratory findings. The absolute numbers of CD3+ T cells, CD4+ T cells, and NK cells were significantly higher in PP group than that in PA group, and were comparable to that in healthy controls. PPP subgroup had markedly reduced B cells and T cells compared to PPN group and healthy subjects. Finally, paired results of these lymphocyte subpopulations from 10 PPN patients demonstrated that the number of T cells and B cells significantly increased when the SARS-CoV-2 tests turned negative. Persistent SARS-CoV-2 presence in non-severe COVID-19 patients is associated with reduced numbers of adaptive immune cells. Monitoring lymphocyte subpopulations could be clinically meaningful in identifying fully recovered COVID-19 patients.


Assuntos
Linfócitos B/citologia , Infecções por Coronavirus/patologia , Pneumonia Viral/patologia , Linfócitos T/citologia , Adulto , Linfócitos B/imunologia , Linfócitos B/metabolismo , Betacoronavirus/isolamento & purificação , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Estudos de Casos e Controles , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Feminino , Humanos , Células Matadoras Naturais/citologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Masculino , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Estudos Retrospectivos , Índice de Gravidade de Doença , Linfócitos T/imunologia , Linfócitos T/metabolismo
12.
Arch Virol ; 165(12): 2869-2876, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33040308

RESUMO

Enzootic bovine leukosis (EBL) is a malignant B cell lymphoma caused by infection with bovine leukemia virus (BLV). Histopathological examination is commonly used for diagnosis of the disease, but observation of lymphoma alone does not confirm EBL because cattle may be affected by sporadic forms of lymphoma that are not associated with BLV. Detection of BLV in tumor cells can be definitive evidence of EBL, but currently, there is no technique available for such a purpose. In this study, we focused on a viral non-coding RNA, AS1, and developed a novel in situ hybridization assay for the detection of BLV from formalin-fixed paraffin-embedded (FFPE) tissues. RNA-seq analysis revealed that all examined B lymphocytes derived from clinical EBL abundantly expressed AS1 RNA, indicating a possible target for detection. The in situ hybridization assay using an AS1 probe clearly detected AS1 RNA in fetal lamb kidney cells persistently infected with BLV. The utility of this assay in clinical samples was assessed using three EBL-derived lymph node specimens and one BLV-negative specimen, and AS1 RNA was detected specifically in the EBL-derived tissues. These results suggest that AS1 RNA is a useful target for the detection of BLV from FFPE specimens of tumor tissues. This technique is expected to become a powerful tool for EBL diagnosis.


Assuntos
Hibridização In Situ , Vírus da Leucemia Bovina/isolamento & purificação , Linfoma de Células B/veterinária , Linfoma de Células B/virologia , RNA não Traduzido/genética , RNA Viral/isolamento & purificação , Animais , Linfócitos B/virologia , Bovinos , Leucose Enzoótica Bovina/virologia , Feminino , Formaldeído , Linfonodos/virologia , Masculino , Inclusão em Parafina , RNA-Seq , Reação em Cadeia da Polimerase em Tempo Real , Ovinos , Fixação de Tecidos
13.
Cell Host Microbe ; 28(4): 499-501, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-33031765

RESUMO

In this issue of Cell Host & Microbe, Nielsen and colleagues sequence antibody repertoires of patients with severe COVID-19 to reveal potentially convergent features on the background of a larger, polyclonal response. Their findings suggest that, as databases improve, it may be possible to monitor virus-specific B cells after infection or vaccination using antibody sequencing.


Assuntos
Infecções por Coronavirus , Pandemias , Pneumonia Viral , Síndrome Respiratória Aguda Grave , Anticorpos Antivirais , Formação de Anticorpos , Linfócitos B , Betacoronavirus , Humanos , Imunoglobulina G
14.
Sci Rep ; 10(1): 16219, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33004978

RESUMO

COVID-19 pandemic has resulted in 16,114,449 cases with 646,641 deaths from the 217 countries, or territories as on July 27th 2020. Due to multifaceted issues and challenges in the implementation of the safety and preventive measures, inconsistent coordination between societies-governments and most importantly lack of specific vaccine to SARS-CoV-2, the spread of the virus that initially emerged at Wuhan is still uprising after taking a heavy toll on human life. In the present study, we mapped immunogenic epitopes present on the four structural proteins of SARS-CoV-2 and we designed a multi-epitope peptide based vaccine that, demonstrated a high immunogenic response with a vast application on world's human population. On codon optimization and in-silico cloning, we found that candidate vaccine showed high expression in E. coli and immune simulation resulted in inducing a high level of both B-cell and T-cell mediated immunity. The results predicted that exposure of vaccine by administrating three injections significantly subsidized the antigen growth in the system. The proposed candidate vaccine found promising by yielding desired results and hence, should be validated by practical experimentations for its functioning and efficacy to neutralize SARS-CoV-2.


Assuntos
Epitopos/imunologia , Simulação de Acoplamento Molecular , Vacinas de Subunidades/imunologia , Vacinas Virais/imunologia , Complexo Antígeno-Anticorpo/química , Complexo Antígeno-Anticorpo/imunologia , Antígenos Virais/imunologia , Linfócitos B/imunologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Epitopos/química , Antígenos HLA/química , Antígenos HLA/imunologia , Humanos , Imunogenicidade da Vacina , Proteínas do Nucleocapsídeo/química , Proteínas do Nucleocapsídeo/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Linfócitos T/imunologia , Receptores Toll-Like/imunologia , Vacinas de Subunidades/química , Proteínas da Matriz Viral/química , Proteínas da Matriz Viral/imunologia , Vacinas Virais/química
15.
mBio ; 11(5)2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978311

RESUMO

The high susceptibility of humans to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the cause of coronavirus disease 2019 (COVID-19), reflects the novelty of the virus and limited preexisting B cell immunity. IgG against the SARS-CoV-2 spike (S) protein, which carries the novel receptor binding domain (RBD), is absent or at low levels in unexposed individuals. To better understand the B cell response to SARS-CoV-2 infection, we asked whether virus-reactive memory B cells (MBCs) were present in unexposed subjects and whether MBC generation accompanied virus-specific IgG production in infected subjects. We analyzed sera and peripheral blood mononuclear cells (PBMCs) from non-SARS-CoV-2-exposed healthy donors and COVID-19 convalescent subjects. Serum IgG levels specific for SARS-CoV-2 proteins (S, including the RBD and S2 subunit, and nucleocapsid [N]) and non-SARS-CoV-2 proteins were related to measurements of circulating IgG MBC levels. Anti-RBD IgG was absent in unexposed subjects. Most unexposed subjects had anti-S2 IgG, and a minority had anti-N IgG, but IgG MBCs with these specificities were not detected, perhaps reflecting low frequencies. Convalescent subjects had high levels of IgG against the RBD, S2, and N, together with large populations of RBD- and S2-reactive IgG MBCs. Notably, IgG titers against the S protein of the human coronavirus OC43 were higher in convalescent subjects than in unexposed subjects and correlated strongly with anti-S2 titers. Our findings indicate cross-reactive B cell responses against the S2 subunit that might enhance broad coronavirus protection. Importantly, our demonstration of MBC induction by SARS-CoV-2 infection suggests that a durable form of B cell immunity is maintained even if circulating antibody levels wane.IMPORTANCE The recent rapid worldwide spread of SARS-CoV-2 has established a pandemic of potentially serious disease in the highly susceptible human population. Key issues are whether humans have preexisting immune memory that provides some protection against SARS-CoV-2 and whether SARS-CoV-2 infection generates lasting immune protection against reinfection. Our analysis focused on pre- and postinfection IgG and IgG memory B cells (MBCs) reactive to SARS-CoV-2 proteins. Most importantly, we demonstrate that infection generates both IgG and IgG MBCs against the novel receptor binding domain and the conserved S2 subunit of the SARS-CoV-2 spike protein. Thus, even if antibody levels wane, long-lived MBCs remain to mediate rapid antibody production. Our study results also suggest that SARS-CoV-2 infection strengthens preexisting broad coronavirus protection through S2-reactive antibody and MBC formation.


Assuntos
Linfócitos B/imunologia , Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Imunoglobulina G/imunologia , Pneumonia Viral/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto , Anticorpos Antivirais/imunologia , Linfócitos B/virologia , Convalescença , Reações Cruzadas , Feminino , Voluntários Saudáveis , Humanos , Memória Imunológica , Masculino , Pessoa de Meia-Idade , Proteínas do Nucleocapsídeo/imunologia , Pandemias , Domínios e Motivos de Interação entre Proteínas , Subunidades Proteicas , Glicoproteína da Espícula de Coronavírus/química
16.
PLoS One ; 15(9): e0239495, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956417

RESUMO

Cell-type specific gene expression profiles are needed for many computational methods operating on bulk RNA-Seq samples, such as deconvolution of cell-type fractions and digital cytometry. However, the gene expression profile of a cell type can vary substantially due to both technical factors and biological differences in cell state and surroundings, reducing the efficacy of such methods. Here, we investigated which factors contribute most to this variation. We evaluated different normalization methods, quantified the variance explained by different factors, evaluated the effect on deconvolution of cell type fractions, and examined the differences between UMI-based single-cell RNA-Seq and bulk RNA-Seq. We investigated a collection of publicly available bulk and single-cell RNA-Seq datasets containing B and T cells, and found that the technical variation across laboratories is substantial, even for genes specifically selected for deconvolution, and this variation has a confounding effect on deconvolution. Tissue of origin is also a substantial factor, highlighting the challenge of using cell type profiles derived from blood with mixtures from other tissues. We also show that much of the differences between UMI-based single-cell and bulk RNA-Seq methods can be explained by the number of read duplicates per mRNA molecule in the single-cell sample. Our work shows the importance of either matching or correcting for technical factors when creating cell-type specific gene expression profiles that are to be used together with bulk samples.


Assuntos
Linfócitos B/química , Análise de Sequência de RNA , Linfócitos T/química , Transcriptoma , Adulto , Composição de Bases , Conjuntos de Dados como Assunto , Sangue Fetal/citologia , Humanos , Recém-Nascido , Análise de Componente Principal , Análise de Célula Única , Manejo de Espécimes
17.
Proc Natl Acad Sci U S A ; 117(38): 23742-23750, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32878998

RESUMO

Ataxin-1 (ATXN1) is a ubiquitous polyglutamine protein expressed primarily in the nucleus where it binds chromatin and functions as a transcriptional repressor. Mutant forms of ataxin-1 containing expanded glutamine stretches cause the movement disorder spinocerebellar ataxia type 1 (SCA1) through a toxic gain-of-function mechanism in the cerebellum. Conversely, ATXN1 loss-of-function is implicated in cancer development and Alzheimer's disease (AD) pathogenesis. ATXN1 was recently nominated as a susceptibility locus for multiple sclerosis (MS). Here, we show that Atxn1-null mice develop a more severe experimental autoimmune encephalomyelitis (EAE) course compared to wildtype mice. The aggravated phenotype is mediated by increased T helper type 1 (Th1) cell polarization, which in turn results from the dysregulation of B cell activity. Ataxin-1 ablation in B cells leads to aberrant expression of key costimulatory molecules involved in proinflammatory T cell differentiation, including cluster of differentiation (CD)44 and CD80. In addition, comprehensive phosphoflow cytometry and transcriptional profiling link the exaggerated proliferation of ataxin-1 deficient B cells to the activation of extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription (STAT) pathways. Lastly, selective deletion of the physiological binding partner capicua (CIC) demonstrates the importance of ATXN1 native interactions for correct B cell functioning. Altogether, we report a immunomodulatory role for ataxin-1 and provide a functional description of the ATXN1 locus genetic association with MS risk.


Assuntos
Ataxina-1/metabolismo , Linfócitos B/metabolismo , Encefalomielite Autoimune Experimental/metabolismo , Animais , Apresentação do Antígeno , Proliferação de Células , Encefalomielite Autoimune Experimental/fisiopatologia , Camundongos , Camundongos Knockout , Esclerose Múltipla , Transdução de Sinais
18.
Proc Natl Acad Sci U S A ; 117(38): 23674-23683, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32907933

RESUMO

The gut microbiome has garnered attention as an effective target to boost immunity and improve cancer immunotherapy. We found that B cell-defective (BCD) mice, such as µ-membrane targeted deletion (µMT) and activation-induced cytidine deaminase (AID) knockouts (KOs), have elevated antitumor immunity under specific pathogen-free but not germ-free conditions. Microbial dysbiosis in these BCD mice enriched the type I IFN (IFN) signature in mucosal CD8+ T cells, resulting in up-regulation of the type I IFN-inducible protein stem cell antigen-1 (Sca-1). Among CD8+ T cells, naïve cells predominantly circulate from the gut to the periphery, and those that had migrated from the mesenteric lymph nodes (mLNs) to the periphery had significantly higher expression of Sca-1. The gut-educated Sca-1+ naïve subset is endowed with enhanced mitochondrial activity and antitumor effector potential. The heterogeneity and functional versatility of the systemic naïve CD8+ T cell compartment was revealed by single-cell analysis and functional assays of CD8+ T cell subpopulations. These results indicate one of the potential mechanisms through which microbial dysbiosis regulates antitumor immunity.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Microbioma Gastrointestinal/imunologia , Interferon Tipo I/imunologia , Neoplasias Experimentais/imunologia , Animais , Antígenos Ly/imunologia , Antígenos Ly/metabolismo , Linfócitos B , Linhagem Celular Tumoral , Células Cultivadas , Disbiose/imunologia , Imunoglobulina A/imunologia , Imunoglobulina A/metabolismo , Interferon Tipo I/metabolismo , Linfonodos/citologia , Proteínas de Membrana/imunologia , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais/imunologia
19.
Cell ; 183(1): 143-157.e13, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32877699

RESUMO

Humoral responses in coronavirus disease 2019 (COVID-19) are often of limited durability, as seen with other human coronavirus epidemics. To address the underlying etiology, we examined post mortem thoracic lymph nodes and spleens in acute SARS-CoV-2 infection and observed the absence of germinal centers and a striking reduction in Bcl-6+ germinal center B cells but preservation of AID+ B cells. Absence of germinal centers correlated with an early specific block in Bcl-6+ TFH cell differentiation together with an increase in T-bet+ TH1 cells and aberrant extra-follicular TNF-α accumulation. Parallel peripheral blood studies revealed loss of transitional and follicular B cells in severe disease and accumulation of SARS-CoV-2-specific "disease-related" B cell populations. These data identify defective Bcl-6+ TFH cell generation and dysregulated humoral immune induction early in COVID-19 disease, providing a mechanistic explanation for the limited durability of antibody responses in coronavirus infections, and suggest that achieving herd immunity through natural infection may be difficult.


Assuntos
Infecções por Coronavirus/imunologia , Centro Germinativo/imunologia , Pneumonia Viral/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Idoso , Idoso de 80 Anos ou mais , Linfócitos B/imunologia , Feminino , Centro Germinativo/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , Proteínas Proto-Oncogênicas c-bcl-6/genética , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Baço/imunologia , Baço/patologia , Fator de Necrose Tumoral alfa/metabolismo
20.
Eur J Immunol ; 50(9): 1283-1294, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32910469

RESUMO

Studies on the interactions between SARS-CoV-2 and humoral immunity are fundamental to elaborate effective therapies including vaccines. We used polychromatic flow cytometry, coupled with unsupervised data analysis and principal component analysis (PCA), to interrogate B cells in untreated patients with COVID-19 pneumonia. COVID-19 patients displayed normal plasma levels of the main immunoglobulin classes, of antibodies against common antigens or against antigens present in common vaccines. However, we found a decreased number of total and naïve B cells, along with decreased percentages and numbers of memory switched and unswitched B cells. On the contrary, IgM+ and IgM- plasmablasts were significantly increased. In vitro cell activation revealed that B lymphocytes showed a normal proliferation index and number of dividing cells per cycle. PCA indicated that B-cell number, naive and memory B cells but not plasmablasts clustered with patients who were discharged, while plasma IgM level, C-reactive protein, D-dimer, and SOFA score with those who died. In patients with pneumonia, the derangement of the B-cell compartment could be one of the causes of the immunological failure to control SARS-Cov2, have a relevant influence on several pathways, organs and systems, and must be considered to develop vaccine strategies.


Assuntos
Anticorpos Antivirais/sangue , Linfócitos B/imunologia , Betacoronavirus/patogenicidade , Infecções por Coronavirus/imunologia , Isotipos de Imunoglobulinas/sangue , Pulmão/imunologia , Pneumonia Viral/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/classificação , Linfócitos B/virologia , Betacoronavirus/imunologia , Proteína C-Reativa/imunologia , Estudos de Casos e Controles , Proliferação de Células , Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Estudos Transversais , Citocinas/genética , Citocinas/imunologia , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/imunologia , Humanos , Imunidade Humoral , Memória Imunológica , Pulmão/patologia , Pulmão/virologia , Ativação Linfocitária , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Escores de Disfunção Orgânica , Pandemias , Pneumonia Viral/mortalidade , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Cultura Primária de Células , Índice de Gravidade de Doença , Análise de Sobrevida
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA