RESUMO
Immune cells use a variety of membrane-disrupting proteins [complement, perforin, perforin-2, granulysin, gasdermins, mixed lineage kinase domain-like pseudokinase (MLKL)] to induce different kinds of death of microbes and host cells, some of which cause inflammation. After activation by proteolytic cleavage or phosphorylation, these proteins oligomerize, bind to membrane lipids, and disrupt membrane integrity. These membrane disruptors play a critical role in both innate and adaptive immunity. Here we review our current knowledge of the functions, specificity, activation, and regulation of membrane-disrupting immune proteins and what is known about the mechanisms behind membrane damage, the structure of the pores they form, how the cells expressing these lethal proteins are protected, and how cells targeted for destruction can sometimes escape death by repairing membrane damage.
Assuntos
Citotoxicidade Imunológica , Interações Hospedeiro-Patógeno/imunologia , Imunidade , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Animais , Apoptose/genética , Apoptose/imunologia , Biomarcadores , Membrana Celular/imunologia , Membrana Celular/metabolismo , Complexo de Ataque à Membrana do Sistema Complemento , Proteínas do Sistema Complemento/imunologia , Proteínas do Sistema Complemento/metabolismo , Regulação da Expressão Gênica , Humanos , Sistema Imunitário/imunologia , Sistema Imunitário/metabolismo , Metabolismo dos Lipídeos , Necroptose/genética , Necroptose/imunologia , Necrose/genética , Necrose/imunologia , Necrose/metabolismo , Proteínas Citotóxicas Formadoras de Poros/química , Proteínas Citotóxicas Formadoras de Poros/genética , Relação Estrutura-AtividadeRESUMO
Neonatal CD4+ and CD8+ T cells have historically been characterized as immature or defective. However, recent studies prompt a reinterpretation of the functions of neonatal T cells. Rather than a population of cells always falling short of expectations set by their adult counterparts, neonatal T cells are gaining recognition as a distinct population of lymphocytes well suited for the rapidly changing environment in early life. In this review, I will highlight new evidence indicating that neonatal T cells are not inert or less potent versions of adult T cells but instead are a broadly reactive layer of T cells poised to quickly develop into regulatory or effector cells, depending on the needs of the host. In this way, neonatal T cells are well adapted to provide fast-acting immune protection against foreign pathogens, while also sustaining tolerance to self-antigens.
Assuntos
Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Imunidade Adaptativa , Animais , Biomarcadores , Diferenciação Celular/imunologia , Interações Hospedeiro-Patógeno , Humanos , Memória Imunológica , Ativação Linfocitária/imunologia , Células Progenitoras Linfoides/citologia , Células Progenitoras Linfoides/imunologia , Células Progenitoras Linfoides/metabolismo , Fenótipo , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais , Subpopulações de Linfócitos T/citologiaRESUMO
SARS-CoV-2 and other sarbecoviruses continue to threaten humanity, highlighting the need to characterize common mechanisms of viral immune evasion for pandemic preparedness. Cytotoxic lymphocytes are vital for antiviral immunity and express NKG2D, an activating receptor conserved among mammals that recognizes infection-induced stress ligands (e.g., MIC-A/B). We found that SARS-CoV-2 evades NKG2D recognition by surface downregulation of MIC-A/B via shedding, observed in human lung tissue and COVID-19 patient serum. Systematic testing of SARS-CoV-2 proteins revealed that ORF6, an accessory protein uniquely conserved among sarbecoviruses, was responsible for MIC-A/B downregulation via shedding. Further investigation demonstrated that natural killer (NK) cells efficiently killed SARS-CoV-2-infected cells and limited viral spread. However, inhibition of MIC-A/B shedding with a monoclonal antibody, 7C6, further enhanced NK-cell activity toward SARS-CoV-2-infected cells. Our findings unveil a strategy employed by SARS-CoV-2 to evade cytotoxic immunity, identify the culprit immunevasin shared among sarbecoviruses, and suggest a potential novel antiviral immunotherapy.
Assuntos
COVID-19 , Evasão da Resposta Imune , Células Matadoras Naturais , Subfamília K de Receptores Semelhantes a Lectina de Células NK , SARS-CoV-2 , Humanos , SARS-CoV-2/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , COVID-19/imunologia , COVID-19/virologia , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Animais , Citotoxicidade Imunológica , Regulação para Baixo , Pulmão/imunologia , Pulmão/virologia , Pulmão/patologiaRESUMO
Senescent cell accumulation has been implicated in the pathogenesis of aging-associated diseases, including cancer. The mechanism that prevents the accumulation of senescent cells in aging human organs is unclear. Here, we demonstrate that a virus-immune axis controls the senescent fibroblast accumulation in the human skin. Senescent fibroblasts increased in old skin compared with young skin. However, they did not increase with advancing age in the elderly. Increased CXCL9 and cytotoxic CD4+ T cells (CD4 CTLs) recruitment were significantly associated with reduced senescent fibroblasts in the old skin. Senescent fibroblasts expressed human leukocyte antigen class II (HLA-II) and human cytomegalovirus glycoprotein B (HCMV-gB), becoming direct CD4 CTL targets. Skin-resident CD4 CTLs eliminated HCMV-gB+ senescent fibroblasts in an HLA-II-dependent manner, and HCMV-gB activated CD4 CTLs from the human skin. Collectively, our findings demonstrate HCMV reactivation in senescent cells, which CD4 CTLs can directly eliminate through the recognition of the HCMV-gB antigen.
Assuntos
Antineoplásicos , Infecções por Citomegalovirus , Humanos , Idoso , Citomegalovirus , Linfócitos T Citotóxicos , Antígenos HLA , Linfócitos T CD4-Positivos , Senescência CelularRESUMO
Immune checkpoint therapy (ICT) has dramatically altered clinical outcomes for cancer patients and conferred durable clinical benefits, including cure in a subset of patients. Varying response rates across tumor types and the need for predictive biomarkers to optimize patient selection to maximize efficacy and minimize toxicities prompted efforts to unravel immune and non-immune factors regulating the responses to ICT. This review highlights the biology of anti-tumor immunity underlying response and resistance to ICT, discusses efforts to address the current challenges with ICT, and outlines strategies to guide the development of subsequent clinical trials and combinatorial efforts with ICT.
Assuntos
Imunoterapia , Neoplasias , Humanos , Antígeno B7-H1 , Neoplasias/tratamento farmacológico , Ensaios Clínicos como Assunto , Inibidores de Checkpoint Imunológico/administração & dosagemRESUMO
Colorectal cancers (CRCs) arise from precursor polyps whose cellular origins, molecular heterogeneity, and immunogenic potential may reveal diagnostic and therapeutic insights when analyzed at high resolution. We present a single-cell transcriptomic and imaging atlas of the two most common human colorectal polyps, conventional adenomas and serrated polyps, and their resulting CRC counterparts. Integrative analysis of 128 datasets from 62 participants reveals adenomas arise from WNT-driven expansion of stem cells, while serrated polyps derive from differentiated cells through gastric metaplasia. Metaplasia-associated damage is coupled to a cytotoxic immune microenvironment preceding hypermutation, driven partly by antigen-presentation differences associated with tumor cell-differentiation status. Microsatellite unstable CRCs contain distinct non-metaplastic regions where tumor cells acquire stem cell properties and cytotoxic immune cells are depleted. Our multi-omic atlas provides insights into malignant progression of colorectal polyps and their microenvironment, serving as a framework for precision surveillance and prevention of CRC.
Assuntos
Pólipos do Colo/patologia , Neoplasias Colorretais/patologia , Microambiente Tumoral , Imunidade Adaptativa , Adenoma/genética , Adenoma/patologia , Adulto , Idoso , Animais , Carcinogênese/genética , Carcinogênese/patologia , Morte Celular , Diferenciação Celular , Pólipos do Colo/genética , Pólipos do Colo/imunologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/imunologia , Progressão da Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Heterogeneidade Genética , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Mutação/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , RNA-Seq , Reprodutibilidade dos Testes , Análise de Célula Única , Microambiente Tumoral/imunologiaRESUMO
Foxp3+ T regulatory (Treg) cells promote immunological tumor tolerance, but how their immune-suppressive function is regulated in the tumor microenvironment (TME) remains unknown. Here, we used intravital microscopy to characterize the cellular interactions that provide tumor-infiltrating Treg cells with critical activation signals. We found that the polyclonal Treg cell repertoire is pre-enriched to recognize antigens presented by tumor-associated conventional dendritic cells (cDCs). Unstable cDC contacts sufficed to sustain Treg cell function, whereas T helper cells were activated during stable interactions. Contact instability resulted from CTLA-4-dependent downregulation of co-stimulatory B7-family proteins on cDCs, mediated by Treg cells themselves. CTLA-4-blockade triggered CD28-dependent Treg cell hyper-proliferation in the TME, and concomitant Treg cell inactivation was required to achieve tumor rejection. Therefore, Treg cells self-regulate through a CTLA-4- and CD28-dependent feedback loop that adjusts their population size to the amount of local co-stimulation. Its disruption through CTLA-4-blockade may off-set therapeutic benefits in cancer patients.
Assuntos
Antígeno CTLA-4/metabolismo , Retroalimentação Fisiológica , Neoplasias/imunologia , Linfócitos T Reguladores/imunologia , Animais , Células Apresentadoras de Antígenos/imunologia , Antígenos CD28/metabolismo , Proliferação de Células , Células Dendríticas/imunologia , Proteínas de Fluorescência Verde/metabolismo , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Imunoterapia , Interleucina-2/metabolismo , Ligantes , Linfonodos/metabolismo , Ativação Linfocitária/imunologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Fatores de Transcrição NFATC/metabolismo , Neoplasias/patologia , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Microambiente TumoralRESUMO
Lymphocyte migration is essential for adaptive immune surveillance. However, our current understanding of this process is rudimentary, because most human studies have been restricted to immunological analyses of blood and various tissues. To address this knowledge gap, we used an integrated approach to characterize tissue-emigrant lineages in thoracic duct lymph (TDL). The most prevalent immune cells in human and non-human primate efferent lymph were T cells. Cytolytic CD8+ T cell subsets with effector-like epigenetic and transcriptional signatures were clonotypically skewed and selectively confined to the intravascular circulation, whereas non-cytolytic CD8+ T cell subsets with stem-like epigenetic and transcriptional signatures predominated in tissues and TDL. Moreover, these anatomically distinct gene expression profiles were recapitulated within individual clonotypes, suggesting parallel differentiation programs independent of the expressed antigen receptor. Our collective dataset provides an atlas of the migratory immune system and defines the nature of tissue-emigrant CD8+ T cells that recirculate via TDL.
Assuntos
Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Animais , Diferenciação Celular , Células Clonais , Citotoxicidade Imunológica , Epigênese Genética , Humanos , Memória Imunológica , Linfonodos/citologia , Linfonodos/imunologia , Macaca mulatta , Subpopulações de Linfócitos T/imunologia , Transcrição Gênica , Transcriptoma/genéticaRESUMO
Maternal decidual NK (dNK) cells promote placentation, but how they protect against placental infection while maintaining fetal tolerance is unclear. Here we show that human dNK cells highly express the antimicrobial peptide granulysin (GNLY) and selectively transfer it via nanotubes to extravillous trophoblasts to kill intracellular Listeria monocytogenes (Lm) without killing the trophoblast. Transfer of GNLY, but not other cell death-inducing cytotoxic granule proteins, strongly inhibits Lm in human placental cultures and in mouse and human trophoblast cell lines. Placental and fetal Lm loads are lower and pregnancy success is greatly improved in pregnant Lm-infected GNLY-transgenic mice than in wild-type mice that lack GNLY. This immune defense is not restricted to pregnancy; peripheral NK (pNK) cells also transfer GNLY to kill bacteria in macrophages and dendritic cells without killing the host cell. Nanotube transfer of GNLY allows dNK to protect against infection while leaving the maternal-fetal barrier intact.
Assuntos
Antígenos de Diferenciação de Linfócitos T/imunologia , Bactérias/imunologia , Movimento Celular/imunologia , Células Matadoras Naturais/imunologia , Trofoblastos/imunologia , Animais , Linhagem Celular , Linhagem Celular Tumoral , Células Dendríticas/imunologia , Feminino , Células HeLa , Humanos , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Placenta/imunologia , Placenta/microbiologia , Gravidez , Ratos , Células THP-1 , Trofoblastos/microbiologiaRESUMO
Responses to anti-PD-1 immunotherapy occur but are infrequent in bladder cancer. The specific T cells that mediate tumor rejection are unknown. T cells from human bladder tumors and non-malignant tissue were assessed with single-cell RNA and paired T cell receptor (TCR) sequencing of 30,604 T cells from 7 patients. We find that the states and repertoires of CD8+ T cells are not distinct in tumors compared with non-malignant tissues. In contrast, single-cell analysis of CD4+ T cells demonstrates several tumor-specific states, including multiple distinct states of regulatory T cells. Surprisingly, we also find multiple cytotoxic CD4+ T cell states that are clonally expanded. These CD4+ T cells can kill autologous tumors in an MHC class II-dependent fashion and are suppressed by regulatory T cells. Further, a gene signature of cytotoxic CD4+ T cells in tumors predicts a clinical response in 244 metastatic bladder cancer patients treated with anti-PD-L1.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/metabolismo , Antígeno B7-H1/genética , Antígeno B7-H1/imunologia , Biomarcadores Farmacológicos/análise , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Genes MHC da Classe II , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Imunoterapia , Linfócitos do Interstício Tumoral , Receptor de Morte Celular Programada 1/genética , Receptores de Antígenos de Linfócitos T/genética , Análise de Célula Única/métodos , Linfócitos T Reguladores , Neoplasias da Bexiga Urinária/imunologiaRESUMO
Checkpoint blockade with antibodies specific for the PD-1 and CTLA-4 inhibitory receptors can induce durable responses in a wide range of human cancers. However, the immunological mechanisms responsible for severe inflammatory side effects remain poorly understood. Here we report a comprehensive single-cell analysis of immune cell populations in colitis, a common and severe side effect of checkpoint blockade. We observed a striking accumulation of CD8 T cells with highly cytotoxic and proliferative states and no evidence of regulatory T cell depletion. T cell receptor (TCR) sequence analysis demonstrated that a substantial fraction of colitis-associated CD8 T cells originated from tissue-resident populations, explaining the frequently early onset of colitis symptoms following treatment initiation. Our analysis also identified cytokines, chemokines, and surface receptors that could serve as therapeutic targets for colitis and potentially other inflammatory side effects of checkpoint blockade.
Assuntos
Linfócitos T CD8-Positivos/citologia , Antígeno CTLA-4/imunologia , Colite/metabolismo , Inibidores de Checkpoint Imunológico/efeitos adversos , Imunoterapia/efeitos adversos , Células Mieloides/metabolismo , Receptores de Quimiocinas/metabolismo , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Antígeno CTLA-4/metabolismo , Quimiocinas/metabolismo , Colite/tratamento farmacológico , Colite/genética , Colite/imunologia , Citocinas/metabolismo , Citometria de Fluxo , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Humanos , Inflamação/tratamento farmacológico , Inflamação/genética , Inflamação/metabolismo , Melanoma/genética , Melanoma/imunologia , Melanoma/metabolismo , Família Multigênica , Células Mieloides/citologia , RNA-Seq , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores CXCR3/genética , Receptores CXCR3/metabolismo , Receptores CXCR6/genética , Receptores CXCR6/metabolismo , Receptores de Quimiocinas/genética , Análise de Célula Única , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/metabolismoRESUMO
The contribution of CD4+ T cells to protective or pathogenic immune responses to SARS-CoV-2 infection remains unknown. Here, we present single-cell transcriptomic analysis of >100,000 viral antigen-reactive CD4+ T cells from 40 COVID-19 patients. In hospitalized patients compared to non-hospitalized patients, we found increased proportions of cytotoxic follicular helper cells and cytotoxic T helper (TH) cells (CD4-CTLs) responding to SARS-CoV-2 and reduced proportion of SARS-CoV-2-reactive regulatory T cells (TREG). Importantly, in hospitalized COVID-19 patients, a strong cytotoxic TFH response was observed early in the illness, which correlated negatively with antibody levels to SARS-CoV-2 spike protein. Polyfunctional TH1 and TH17 cell subsets were underrepresented in the repertoire of SARS-CoV-2-reactive CD4+ T cells compared to influenza-reactive CD4+ T cells. Together, our analyses provide insights into the gene expression patterns of SARS-CoV-2-reactive CD4+ T cells in distinct disease severities.
Assuntos
COVID-19/imunologia , SARS-CoV-2/genética , Células T Auxiliares Foliculares/imunologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Reguladores/imunologia , Transcriptoma , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Contagem de Linfócito CD4 , COVID-19/epidemiologia , COVID-19/virologia , Estudos de Coortes , Inglaterra/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Índice de Gravidade de Doença , Análise de Célula Única/métodos , Glicoproteína da Espícula de Coronavírus/imunologiaRESUMO
Inflammatory disorders of the CNS are frequently accompanied by synaptic loss, which is thought to involve phagocytic microglia and complement components. However, the mechanisms accounting for aberrant synaptic connectivity in the context of CD8+ T cell-driven neuronal damage are poorly understood. Here, we profiled the neuronal translatome in a murine model of encephalitis caused by CD8+ T cells targeting antigenic neurons. Neuronal STAT1 signaling and downstream CCL2 expression were essential for apposition of phagocytes, ensuing synaptic loss and neurological disease. Analogous observations were made in the brains of Rasmussen's encephalitis patients. In this devastating CD8+ T cell-driven autoimmune disease, neuronal STAT1 phosphorylation and CCL2 expression co-clustered with infiltrating CD8+ T cells as well as phagocytes. Taken together, our findings uncover an active role of neurons in coordinating phagocyte-mediated synaptic loss and highlight neuronal STAT1 and CCL2 as critical steps in this process that are amenable to pharmacological interventions.
Assuntos
Neurônios/metabolismo , Fagocitose/fisiologia , Sinapses/fisiologia , Animais , Encéfalo/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Quimiocina CCL2/genética , Quimiocina CCL2/fisiologia , Modelos Animais de Doenças , Encefalite/genética , Encefalite/imunologia , Encefalite/fisiopatologia , Feminino , Humanos , Inflamação/imunologia , Inflamação/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Doenças do Sistema Nervoso/metabolismo , Neurônios/fisiologia , Fagócitos/imunologia , Fagócitos/metabolismo , Fagocitose/imunologia , Fosforilação , Fator de Transcrição STAT1/fisiologia , Transcriptoma/genéticaRESUMO
Glioblastoma (GBM), a highly lethal brain cancer, is notorious for immunosuppression, but the mechanisms remain unclear. Here, we documented a temporospatial patterning of tumor-associated myeloid cells (TAMs) corresponding to vascular changes during GBM progression. As tumor vessels transitioned from the initial dense regular network to later scant and engorged vasculature, TAMs shifted away from perivascular regions and trafficked to vascular-poor areas. This process was heavily influenced by the immunocompetence state of the host. Utilizing a sensitive fluorescent UnaG reporter to track tumor hypoxia, coupled with single-cell transcriptomics, we revealed that hypoxic niches attracted and sequestered TAMs and cytotoxic T lymphocytes (CTLs), where they were reprogrammed toward an immunosuppressive state. Mechanistically, we identified chemokine CCL8 and cytokine IL-1ß as two hypoxic-niche factors critical for TAM trafficking and co-evolution of hypoxic zones into pseudopalisading patterns. Therefore, perturbation of TAM patterning in hypoxic zones may improve tumor control.
Assuntos
Glioblastoma , Linfócitos T Citotóxicos , Humanos , Macrófagos Associados a Tumor , Macrófagos , Terapia de Imunossupressão , Glioblastoma/patologia , Microambiente TumoralRESUMO
Local environmental factors influence CD8+ T cell priming in lymph nodes (LNs). Here, we sought to understand how factors unique to the tumor-draining mediastinal LN (mLN) impact CD8+ T cell responses toward lung cancer. Type 1 conventional dendritic cells (DC1s) showed a mLN-specific failure to induce robust cytotoxic T cells responses. Using regulatory T (Treg) cell depletion strategies, we found that Treg cells suppressed DC1s in a spatially coordinated manner within tissue-specific microniches within the mLN. Treg cell suppression required MHC II-dependent contact between DC1s and Treg cells. Elevated levels of IFN-γ drove differentiation Treg cells into Th1-like effector Treg cells in the mLN. In patients with cancer, Treg cell Th1 polarization, but not CD8+/Treg cell ratios, correlated with poor responses to checkpoint blockade immunotherapy. Thus, IFN-γ in the mLN skews Treg cells to be Th1-like effector Treg cells, driving their close interaction with DC1s and subsequent suppression of cytotoxic T cell responses.
Assuntos
Neoplasias Pulmonares , Linfócitos T Reguladores , Humanos , Linfócitos T CD8-Positivos , Interferon gama , Linfócitos T CitotóxicosRESUMO
Human cytotoxic lymphocytes kill intracellular microbes. The cytotoxic granule granzyme proteases released by cytotoxic lymphocytes trigger oxidative bacterial death by disrupting electron transport, generating superoxide anion and inactivating bacterial oxidative defenses. However, they also cause non-oxidative cell death because anaerobic bacteria are also killed. Here, we use differential proteomics to identify granzyme B substrates in three unrelated bacteria: Escherichia coli, Listeria monocytogenes, and Mycobacteria tuberculosis. Granzyme B cleaves a highly conserved set of proteins in all three bacteria, which function in vital biosynthetic and metabolic pathways that are critical for bacterial survival under diverse environmental conditions. Key proteins required for protein synthesis, folding, and degradation are also substrates, including multiple aminoacyl tRNA synthetases, ribosomal proteins, protein chaperones, and the Clp system. Because killer cells use a multipronged strategy to target vital pathways, bacteria may not easily become resistant to killer cell attack.
Assuntos
Escherichia coli/citologia , Granzimas/metabolismo , Células Matadoras Naturais/enzimologia , Listeria monocytogenes/citologia , Mycobacterium tuberculosis/citologia , Linfócitos T Citotóxicos/enzimologia , Aminoacil-tRNA Sintetases/metabolismo , Animais , Escherichia coli/metabolismo , Humanos , Células Matadoras Naturais/imunologia , Listeria monocytogenes/metabolismo , Redes e Vias Metabólicas , Camundongos , Mycobacterium tuberculosis/metabolismo , Biossíntese de Proteínas , Proteômica , Ribossomos/metabolismo , Linfócitos T Citotóxicos/imunologiaRESUMO
The gut microbiota contributes to the development of normal immunity but, when dysregulated, can promote autoimmunity through various non-antigen-specific effects on pathogenic and regulatory lymphocytes. Here, we show that an integrase expressed by several species of the gut microbial genus Bacteroides encodes a low-avidity mimotope of the pancreatic ß cell autoantigen islet-specific glucose-6-phosphatase-catalytic-subunit-related protein (IGRP206-214). Studies in germ-free mice monocolonized with integrase-competent, integrase-deficient, and integrase-transgenic Bacteroides demonstrate that the microbial epitope promotes the recruitment of diabetogenic CD8+ T cells to the gut. There, these effectors suppress colitis by targeting microbial antigen-loaded, antigen-presenting cells in an integrin ß7-, perforin-, and major histocompatibility complex class I-dependent manner. Like their murine counterparts, human peripheral blood T cells also recognize Bacteroides integrase. These data suggest that gut microbial antigen-specific cytotoxic T cells may have therapeutic value in inflammatory bowel disease and unearth molecular mimicry as a novel mechanism by which the gut microbiota can regulate normal immune homeostasis. PAPERCLIP.
Assuntos
Autoantígenos/imunologia , Bacteroides/imunologia , Colite/imunologia , Microbioma Gastrointestinal , Glucose-6-Fosfatase/imunologia , Adulto , Animais , Bacteroides/classificação , Bacteroides/enzimologia , Colite/microbiologia , Feminino , Glucose-6-Fosfatase/genética , Humanos , Tecido Linfoide/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Pessoa de Meia-Idade , Mimetismo Molecular , Linfócitos T/imunologiaRESUMO
The intestinal epithelium comprises the body's largest surface exposed to viruses. Additionally, the gut epithelium hosts a large population of intraepithelial T lymphocytes, or IELs, although their role in resistance against viral infections remains elusive. By fate-mapping T cells recruited to the murine intestine, we observed an accumulation of newly recruited CD4+ T cells after infection with murine norovirus CR6 and adenovirus type-2 (AdV), but not reovirus. CR6- and AdV-recruited intraepithelial CD4+ T cells co-expressed Ly6A and chemokine receptor CCR9, exhibited T helper 1 and cytotoxic profiles, and conferred protection against AdV in vivo and in an organoid model in an IFN-γ-dependent manner. Ablation of the T cell receptor (TCR) or the transcription factor ThPOK in CD4+ T cells prior to AdV infection prevented viral control, while TCR ablation during infection did not impact viral clearance. These results uncover a protective role for intraepithelial Ly6A+CCR9+CD4+ T cells against enteric adenovirus.
Assuntos
Intestino Delgado , Viroses , Animais , Antígenos Ly , Linfócitos T CD4-Positivos , Mucosa Intestinal , Proteínas de Membrana , Camundongos , Receptores de QuimiocinasRESUMO
Understanding the drivers and markers of clonally expanding HIV-1-infected CD4+ T cells is essential for HIV-1 eradication. We used single-cell ECCITE-seq, which captures surface protein expression, cellular transcriptome, HIV-1 RNA, and TCR sequences within the same single cell to track clonal expansion dynamics in longitudinally archived samples from six HIV-1-infected individuals (during viremia and after suppressive antiretroviral therapy) and two uninfected individuals, in unstimulated conditions and after CMV and HIV-1 antigen stimulation. Despite antiretroviral therapy, persistent antigen and TNF responses shaped T cell clonal expansion. HIV-1 resided in Th1-polarized, antigen-responding T cells expressing BCL2 and SERPINB9 that may resist cell death. HIV-1 RNA+ T cell clones were larger in clone size, established during viremia, persistent after viral suppression, and enriched in GZMB+ cytotoxic effector memory Th1 cells. Targeting HIV-1-infected cytotoxic CD4+ T cells and drivers of clonal expansion provides another direction for HIV-1 eradication.
Assuntos
Infecções por HIV , HIV-1 , Linfócitos T CD4-Positivos , Células Clonais , Humanos , RNA , ViremiaRESUMO
Inflammation can support or restrain cancer progression and the response to therapy. Here, we searched for primary regulators of cancer-inhibitory inflammation through deep profiling of inflammatory tumor microenvironments (TMEs) linked to immune-dependent control in mice. We found that early intratumoral accumulation of interferon gamma (IFN-γ)-producing natural killer (NK) cells induced a profound remodeling of the TME and unleashed cytotoxic T cell (CTL)-mediated tumor eradication. Mechanistically, tumor-derived prostaglandin E2 (PGE2) acted selectively on EP2 and EP4 receptors on NK cells, hampered the TME switch, and enabled immune evasion. Analysis of patient datasets across human cancers revealed distinct inflammatory TME phenotypes resembling those associated with cancer immune control versus escape in mice. This allowed us to generate a gene-expression signature that integrated opposing inflammatory factors and predicted patient survival and response to immune checkpoint blockade. Our findings identify features of the tumor inflammatory milieu associated with immune control of cancer and establish a strategy to predict immunotherapy outcomes.