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1.
Artigo em Inglês | MEDLINE | ID: mdl-33444817

RESUMO

BACKGROUND & AIMS: Noroviruses (NoVs) are the leading cause of acute gastroenteritis worldwide and are associated with significant morbidity and mortality. Moreover, an asymptomatic carrier state can persist following acute infection, promoting NoV spread and evolution. Thus, defining immune correlates of NoV protection and persistence is needed to guide the development of future vaccines and limit viral spread. Whereas antibody responses following NoV infection or vaccination have been studied extensively, cellular immunity has received less attention. Data from the mouse NoV model suggest that T cells are critical for preventing persistence and achieving viral clearance, but little is known about NoV-specific T-cell immunity in humans, particularly at mucosal sites. METHODS: We screened peripheral blood mononuclear cells from 3 volunteers with an overlapping NoV peptide library. We then used HLA-peptide tetramers to track virus-specific CD8+ T cells in peripheral, lymphoid, and intestinal tissues. Tetramer+ cells were further characterized using markers for cellular trafficking, exhaustion, cytotoxicity, and proliferation. RESULTS: We defined 7 HLA-restricted immunodominant class I epitopes that were highly conserved across pandemic strains from genogroup II.4. NoV-specific CD8+ T cells with central, effector, or tissue-resident memory phenotypes were present at all sites and were especially abundant in the intestinal lamina propria. The properties and differentiation states of tetramer+ cells varied across donors and epitopes. CONCLUSIONS: Our findings are an important step toward defining the breadth, distribution, and properties of human NoV T-cell immunity. Moreover, the molecular tools we have developed can be used to evaluate future vaccines and engineer novel cellular therapeutics.

2.
Sci Immunol ; 6(55)2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452106

RESUMO

The developmental origins of memory T cells remain incompletely understood. During the expansion phase of acute viral infection, we identified a distinct subset of virus-specific CD8+ T cells that possessed distinct characteristics including expression of CD62L, T cell factor 1 (TCF-1), and Eomesodermin; relative quiescence; expression of activation markers; and features of limited effector differentiation. These cells were a quantitatively minor subpopulation of the TCF-1+ pool and exhibited self-renewal, heightened DNA damage surveillance activity, and preferential long-term recall capacity. Despite features of memory and somewhat restrained proliferation during the expansion phase, this subset displayed evidence of stronger TCR signaling than other responding CD8+ T cells, coupled with elevated expression of multiple inhibitory receptors including programmed cell death 1 (PD-1), lymphocyte activating gene 3 (LAG-3), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), CD5, and CD160. Genetic ablation of PD-1 and LAG-3 compromised the formation of this CD62Lhi TCF-1+ subset and subsequent CD8+ T cell memory. Although central memory phenotype CD8+ T cells were formed in the absence of these cells, subsequent memory CD8+ T cell recall responses were compromised. Together, these results identify an important link between genome integrity maintenance and CD8+ T cell memory. Moreover, the data indicate a role for inhibitory receptors in preserving key memory CD8+ T cell precursors during initial activation and differentiation. Identification of this rare subpopulation within the memory CD8+ T cell precursor pool may help reconcile models of the developmental origin of long-term CD8+ T cell memory.

3.
Mucosal Immunol ; 11(6): 1684-1693, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30111863

RESUMO

Simultaneous analyses of peripheral and mucosal immune compartments can yield insight into the pathogenesis of mucosal-associated diseases. Although methods to preserve peripheral immune cells are well established, studies involving mucosal immune cells have been hampered by lack of simple storage techniques. We provide a cryopreservation protocol allowing for storage of gastrointestinal (GI) tissue with preservation of viability and functionality of both immune and epithelial cells. These methods will facilitate translational studies allowing for batch analysis of mucosal tissue to investigate disease pathogenesis, biomarker discovery and treatment responsiveness.


Assuntos
Criopreservação/métodos , Imunofenotipagem/métodos , Mucosa Intestinal/imunologia , Intestinos/fisiologia , Sobrevivência Celular , Perfilação da Expressão Gênica , Humanos , Intestinos/patologia
4.
Immunity ; 47(4): 723-738.e5, 2017 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-29031786

RESUMO

Noroviruses can establish chronic infections with active viral shedding in healthy humans but whether persistence is associated with adaptive immune dysfunction is unknown. We used genetically engineered strains of mouse norovirus (MNV) to investigate CD8+ T cell differentiation during chronic infection. We found that chronic infection drove MNV-specific tissue-resident memory (Trm) CD8+ T cells to a differentiation state resembling inflationary effector responses against latent cytomegalovirus with only limited evidence of exhaustion. These MNV-specific Trm cells remained highly functional yet appeared ignorant of ongoing viral replication. Pre-existing MNV-specific Trm cells provided partial protection against chronic infection but largely ceased to detect virus within 72 hours of challenge, demonstrating rapid sequestration of viral replication away from T cells. Our studies revealed a strategy of immune evasion by MNV via the induction of a CD8+ T cell program normally reserved for latent pathogens and persistence in an immune-privileged enteric niche.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Infecções por Caliciviridae/imunologia , Diferenciação Celular/imunologia , Gastroenterite/imunologia , Norovirus/imunologia , Animais , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/virologia , Infecções por Caliciviridae/genética , Infecções por Caliciviridae/virologia , Diferenciação Celular/genética , Linhagem Celular , Microambiente Celular/genética , Microambiente Celular/imunologia , Gastroenterite/genética , Gastroenterite/virologia , Perfilação da Expressão Gênica/métodos , Ontologia Genética , Células HEK293 , Interações Hospedeiro-Patógeno/imunologia , Humanos , Memória Imunológica/genética , Memória Imunológica/imunologia , Camundongos Endogâmicos C57BL , Norovirus/fisiologia , Análise de Sequência com Séries de Oligonucleotídeos/métodos
5.
Nat Rev Gastroenterol Hepatol ; 14(10): 573-584, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28743984

RESUMO

A general consensus exists that IBD is associated with compositional and metabolic changes in the intestinal microbiota (dysbiosis). However, a direct causal relationship between dysbiosis and IBD has not been definitively established in humans. Findings from animal models have revealed diverse and context-specific roles of the gut microbiota in health and disease, ranging from protective to pro-inflammatory actions. Moreover, evidence from these experimental models suggest that although gut bacteria often drive immune activation, chronic inflammation in turn shapes the gut microbiota and contributes to dysbiosis. The purpose of this Review is to summarize current associations between IBD and dysbiosis, describe the role of the gut microbiota in the context of specific animal models of colitis, and discuss the potential role of microbiota-focused interventions in the treatment of human IBD. Ultimately, more studies will be needed to define host-microbial relationships relevant to human disease and amenable to therapeutic interventions.


Assuntos
Disbiose/imunologia , Disbiose/microbiologia , Microbioma Gastrointestinal/imunologia , Doenças Inflamatórias Intestinais/imunologia , Doenças Inflamatórias Intestinais/microbiologia , Animais , Humanos
7.
J Immunol ; 197(4): 1017-22, 2016 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-27430722

RESUMO

The role of Ab and B cells in preventing infection is established. In contrast, the role of B cell responses in containing chronic infections remains poorly understood. IgG2a (IgG1 in humans) can prevent acute infections, and T-bet promotes IgG2a isotype switching. However, whether IgG2a and B cell-expressed T-bet influence the host-pathogen balance during persisting infections is unclear. We demonstrate that B cell-specific loss of T-bet prevents control of persisting viral infection. T-bet in B cells controlled IgG2a production, as well as mucosal localization, proliferation, glycosylation, and a broad transcriptional program. T-bet controlled a broad antiviral program in addition to IgG2a because T-bet in B cells was important, even in the presence of virus-specific IgG2a. Our data support a model in which T-bet is a universal controller of antiviral immunity across multiple immune lineages.


Assuntos
Subpopulações de Linfócitos B/imunologia , Linfócitos B/imunologia , Coriomeningite Linfocítica/imunologia , Proteínas com Domínio T/imunologia , Animais , Separação Celular , Doença Crônica , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Imunoglobulina G/imunologia , Vírus da Coriomeningite Linfocítica , Camundongos , Camundongos Transgênicos , Análise de Sequência com Séries de Oligonucleotídeos
8.
PLoS Pathog ; 12(6): e1005684, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27327515

RESUMO

In order for a virus to persist, there must be a balance between viral replication and immune clearance. It is commonly believed that adaptive immunity drives clearance of viral infections and, thus, dysfunction or viral evasion of adaptive immunity is required for a virus to persist. Type I interferons (IFNs) play pleiotropic roles in the antiviral response, including through innate control of viral replication. Murine norovirus (MNoV) replicates in dendritic cells (DCs) and type I IFN signaling in DCs is important for early control of MNoV replication. We show here that the non-persistent MNoV strain CW3 persists systemically when CD11c positive DCs are unable to respond to type I IFN. Persistence in this setting is associated with increased early viral titers, maintenance of DC numbers, increased expression of DC activation markers and an increase in CD8 T cell and antibody responses. Furthermore, CD8 T cell function is maintained during the persistent phase of infection and adaptive immune cells from persistently infected mice are functional when transferred to Rag1-/- recipients. Finally, increased early replication and persistence are also observed in mixed bone marrow chimeras where only half of the CD11c positive DCs are unable to respond to type I IFN. These findings demonstrate that increased early viral replication due to a cell-intrinsic innate immune deficiency is sufficient for persistence and a functional adaptive immune response is not sufficient for viral clearance.


Assuntos
Infecções por Caliciviridae/imunologia , Células Dendríticas/imunologia , Células Dendríticas/virologia , Interferon Tipo I/imunologia , Receptor de Interferon alfa e beta/imunologia , Imunidade Adaptativa/imunologia , Animais , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Imunidade Inata/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Norovirus , Reação em Cadeia da Polimerase em Tempo Real , Receptor de Interferon alfa e beta/deficiência , Replicação Viral/fisiologia
9.
Science ; 345(6196): 578-82, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-25082704

RESUMO

The mammalian intestine is colonized by beneficial commensal bacteria and is a site of infection by pathogens, including helminth parasites. Helminths induce potent immunomodulatory effects, but whether these effects are mediated by direct regulation of host immunity or indirectly through eliciting changes in the microbiota is unknown. We tested this in the context of virus-helminth coinfection. Helminth coinfection resulted in impaired antiviral immunity and was associated with changes in the microbiota and STAT6-dependent helminth-induced alternative activation of macrophages. Notably, helminth-induced impairment of antiviral immunity was evident in germ-free mice, but neutralization of Ym1, a chitinase-like molecule that is associated with alternatively activated macrophages, could partially restore antiviral immunity. These data indicate that helminth-induced immunomodulation occurs independently of changes in the microbiota but is dependent on Ym1.


Assuntos
Infecções por Caliciviridae/imunologia , Coinfecção/imunologia , Gastroenterite/imunologia , Imunomodulação , Lectinas/imunologia , Microbiota/imunologia , Norovirus/imunologia , Trichinella/imunologia , Triquinelose/imunologia , beta-N-Acetil-Hexosaminidases/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Coinfecção/microbiologia , Coinfecção/parasitologia , Gastroenterite/virologia , Vida Livre de Germes , Intestinos/imunologia , Intestinos/microbiologia , Intestinos/virologia , Ativação de Macrófagos , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL
10.
Inflamm Bowel Dis ; 20(6): 1070-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24810138

RESUMO

BACKGROUND: There is a need for simple, noninvasive patient-driven disease assessment instruments in ulcerative colitis (UC). We sought to further assess and refine the previous described 6-point Mayo score. METHODS: A cross-sectional study of 282 UC patients was conducted assessing the correlation of the 2 patient-reported Mayo score components (6-point Mayo score) with the simple clinical colitis activity index (SCCAI) and a single Likert scale of patient-reported disease activity. Spearman's correlation, sensitivity, specificity, and area under the receiver operating curves (AUC) were calculated. A separate validation study in 59 UC patients was also conducted. RESULTS: Participants predominantly had long-standing disease (83%) and were in self-reported remission (63%). The 6-point Mayo score correlated well with the SCCAI (rho = 0.71; P < 0.0001) and patient-reported disease activity (rho = 0.65; P < 0.0001). Using a cutpoint of 1.5, the 6-point Mayo score had 83% sensitivity and 72% specificity for patient-defined remission, and 89% sensitivity and 67% specificity for SCCAI-defined remission (score, <2.5). The 6-point Mayo score and SCCAI had similar accuracy of predicting patient-defined remission (AUC = 0.84 and 0.87, respectively). Addition of the SCCAI general well-being question to the 6-point Mayo improved the predictive ability for patient-defined remission; and a new weighted score had an AUC of 0.89 in the development cohort and 0.93 in the validation cohort. The optimal cutpoint was 1.6. CONCLUSIONS: The patient-reported UC severity index that includes stool frequency, bleeding, and general well-being accurately measures clinical disease activity without requiring direct physician contact.


Assuntos
Colite Ulcerativa/diagnóstico , Colite Ulcerativa/fisiopatologia , Inquéritos Epidemiológicos/normas , Autorrelato/normas , Índice de Gravidade de Doença , Adulto , Estudos Transversais , Defecação , Feminino , Hemorragia Gastrointestinal/diagnóstico , Hemorragia Gastrointestinal/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Serviços Postais , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade
11.
J Virol ; 87(12): 7015-31, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23596300

RESUMO

Norovirus (NV) gastroenteritis is a major contributor to global morbidity and mortality, yet little is known about immune mechanisms leading to NV control. Previous studies using the murine norovirus (MNV) model have established a key role for T cells in MNV clearance. Despite these advances, important questions remain regarding the magnitude, location, and dynamics of the MNV-specific T cell response. To address these questions, we identified MNV-specific major histocompatibility complex (MHC) class I immunodominant epitopes using an overlapping peptide screen. One of these epitopes (amino acids 519 to 527 of open reading frame 2 [ORF2(519-527)]) was highly conserved among all NV genogroups. Using MHC class I peptide tetramers, we tracked MNV-specific CD8 T cells in lymphoid and mucosal sites during infection with two MNV strains with distinct biological behaviors, the acutely cleared strain CW3 and the persistent strain CR6. Here, we show that enteric MNV infection elicited robust T cell responses primarily in the intestinal mucosa and that MNV-specific CD8 T cells dynamically regulated the expression of surface molecules associated with activation, differentiation, and homing. Furthermore, compared to MNV-CW3 infection, chronic infection with MNV-CR6 resulted in fewer and less-functional CD8 T cells, and this difference was evident as early as day 8 postinfection. Finally, MNV-specific CD8 T cells were capable of reducing the viral load in persistently infected Rag1(-/-) mice, suggesting that these cells are a crucial component of NV immunity. Collectively, these data provide fundamental new insights into the adaptive immune response to two closely related NV strains with distinct biological behaviors and bring us closer to understanding the correlates of protective antiviral immunity in the intestine.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Infecções por Caliciviridae/imunologia , Gastroenterite/imunologia , Mucosa Intestinal , Norovirus/imunologia , Animais , Infecções por Caliciviridae/virologia , Doença Crônica , Epitopos de Linfócito T , Feminino , Citometria de Fluxo , Gastroenterite/virologia , Epitopos Imunodominantes , Mucosa Intestinal/imunologia , Mucosa Intestinal/virologia , Ativação Linfocitária , Complexo Principal de Histocompatibilidade , Camundongos , Camundongos Endogâmicos C57BL
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