RESUMO
Peripheral CD8+ T cell tolerance is a checkpoint in both autoimmune disease and anti-cancer immunity. Despite its importance, the relationship between tolerance-induced states and other CD8+ T cell differentiation states remains unclear. Using flow cytometric phenotyping, single-cell RNA sequencing (scRNA-seq), and chromatin accessibility profiling, we demonstrated that in vivo peripheral tolerance to a self-antigen triggered a fundamentally distinct differentiation state separate from exhaustion, memory, and functional effector cells but analogous to cells defectively primed against tumors. Tolerant cells diverged early and progressively from effector cells, adopting a transcriptionally and epigenetically distinct state within 60 h of antigen encounter. Breaching tolerance required the synergistic actions of strong T cell receptor (TCR) signaling and inflammation, which cooperatively induced gene modules that enhanced protein translation. Weak TCR signaling during bystander infection failed to breach tolerance due to the uncoupling of effector gene expression from protein translation. Thus, tolerance engages a distinct differentiation trajectory enforced by protein translation defects.
Assuntos
Linfócitos T CD8-Positivos , Diferenciação Celular , Tolerância Imunológica , Biossíntese de Proteínas , Receptores de Antígenos de Linfócitos T , Linfócitos T CD8-Positivos/imunologia , Animais , Diferenciação Celular/imunologia , Camundongos , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos de Linfócitos T/imunologia , Tolerância Imunológica/imunologia , Biossíntese de Proteínas/imunologia , Transdução de Sinais/imunologia , Camundongos Endogâmicos C57BL , Autoantígenos/imunologiaRESUMO
Mucosal-associated invariant T cells (MAIT cells) detect microbial vitamin B2 derivatives presented by the antigen-presenting molecule MR1. Here we defined three developmental stages and checkpoints for the MAIT cell lineage in humans and mice. Stage 1 and stage 2 MAIT cells predominated in thymus, while stage 3 cells progressively increased in abundance extrathymically. Transition through each checkpoint was regulated by MR1, whereas the final checkpoint that generated mature functional MAIT cells was controlled by multiple factors, including the transcription factor PLZF and microbial colonization. Furthermore, stage 3 MAIT cell populations were expanded in mice deficient in the antigen-presenting molecule CD1d, suggestive of a niche shared by MAIT cells and natural killer T cells (NKT cells). Accordingly, this study maps the developmental pathway and checkpoints that control the generation of functional MAIT cells.
Assuntos
Diferenciação Celular/imunologia , Células T Invariantes Associadas à Mucosa/citologia , Células T Invariantes Associadas à Mucosa/fisiologia , Timo/imunologia , Timo/metabolismo , Animais , Antígenos CD1d/genética , Biomarcadores , Diferenciação Celular/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Imunofenotipagem , Células Progenitoras Linfoides/imunologia , Células Progenitoras Linfoides/metabolismo , Masculino , Camundongos , Camundongos Knockout , MicroRNAs/genéticaRESUMO
During evolutionary adaptation in the immune system, host defense is traded off against autoreactivity. Signals through the costimulatory receptor CD28 enable T cells to respond specifically to pathogens, whereas those through the related costimulatory receptor, ICOS, which arose by gene duplication, are critical for affinity maturation and memory antibody responses. ICOS ligand, unlike the pathogen-inducible CD28 ligands, is widely and constitutively expressed in the immune system. Here, we show that crosstalk between these two pathways provides a mechanism for obviating the normal T cell dependence on CD28. Several CD28-mediated responses-generation of follicular helper T cells, germinal center formation, T helper 1 cell-dependent extrafollicular antibody responses to Salmonella and bacterial clearance, and regulatory T cell homeostasis-became independent of CD28 and dependent on ICOS when the E3 ubiquitin ligase Roquin was mutated. Mechanisms to functionally compartmentalize ICOS and CD28 signals are thus critical for two-signal control of normal immune reactions.
Assuntos
Antígenos de Diferenciação de Linfócitos T/imunologia , Antígenos CD28/imunologia , Linfócitos T/imunologia , Ubiquitina-Proteína Ligases/imunologia , Alelos , Animais , Antígenos de Diferenciação de Linfócitos T/genética , Antígenos de Diferenciação de Linfócitos T/metabolismo , Antígenos CD28/genética , Antígenos CD28/metabolismo , Diferenciação Celular/imunologia , Regulação da Expressão Gênica , Centro Germinativo/imunologia , Memória Imunológica/imunologia , Proteína Coestimuladora de Linfócitos T Induzíveis , Interleucina-2/imunologia , Interleucina-2/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação/genética , Salmonella/imunologia , Transdução de Sinais/imunologia , Linfócitos T/citologia , Linfócitos T/metabolismo , Timo/citologia , Timo/imunologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Male infertility affects at least 5% of reproductive age males. The most common pathology is a complex presentation of decreased sperm output and abnormal sperm shape and motility referred to as oligoasthenoteratospermia (OAT). For the majority of OAT men a precise diagnosis cannot be provided. Here we demonstrate that leucine-rich repeats and guanylate kinase-domain containing isoform 1 (LRGUK-1) is required for multiple aspects of sperm assembly, including acrosome attachment, sperm head shaping and the initiation of the axoneme growth to form the core of the sperm tail. Specifically, LRGUK-1 is required for basal body attachment to the plasma membrane, the appropriate formation of the sub-distal appendages, the extension of axoneme microtubules and for microtubule movement and organisation within the manchette. Manchette dysfunction leads to abnormal sperm head shaping. Several of these functions may be achieved in association with the LRGUK-1 binding partner HOOK2. Collectively, these data establish LRGUK-1 as a major determinant of microtubule structure within the male germ line.
Assuntos
Guanilato Quinases/metabolismo , Infertilidade Masculina/metabolismo , Espermatogênese , Espermatozoides/metabolismo , Sequência de Aminoácidos , Animais , Corpos Basais/metabolismo , Membrana Celular/metabolismo , Guanilato Quinases/química , Guanilato Quinases/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Associadas aos Microtúbulos/metabolismo , Dados de Sequência Molecular , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Alinhamento de Sequência , Espermatozoides/citologia , Testículo/citologia , Testículo/metabolismoRESUMO
MOTIVATION: Increasingly, cost-effective high-throughput DNA sequencing technologies are being utilized to sequence human pedigrees to elucidate the genetic cause of a wide variety of human diseases. While numerous tools exist for variant prioritization within a single genome, the ability to concurrently analyze variants within pedigrees remains a challenge, especially should there be no prior indication of the underlying genetic cause of the disease. Here, we present a tool, variant analysis of sequenced pedigrees (VASP), a flexible data integration environment capable of producing a summary of pedigree variation, providing relevant information such as compound heterozygosity, genome phasing and disease inheritance patterns. Designed to aggregate data across a sequenced pedigree, VASP allows both powerful filtering and custom prioritization of both single nucleotide variants (SNVs) and small indels. Hence, clinical and research users with prior knowledge of a disease are able to dramatically reduce the variant search space based on a wide variety of custom prioritization criteria. AVAILABILITY AND IMPLEMENTATION: Source code available for academic non-commercial research purposes at https://github.com/mattmattmattmatt/VASP.
Assuntos
Ligação Genética , Predisposição Genética para Doença , Variação Genética/genética , Software , Feminino , Marcadores Genéticos/genética , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Mutação INDEL/genética , Masculino , Linhagem , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
Katanin is an evolutionarily conserved microtubule-severing complex implicated in multiple aspects of microtubule dynamics. Katanin consists of a p60 severing enzyme and a p80 regulatory subunit. The p80 subunit is thought to regulate complex targeting and severing activity, but its precise role remains elusive. In lower-order species, the katanin complex has been shown to modulate mitotic and female meiotic spindle dynamics and flagella development. The in vivo function of katanin p80 in mammals is unknown. Here we show that katanin p80 is essential for male fertility. Specifically, through an analysis of a mouse loss-of-function allele (the Taily line), we demonstrate that katanin p80, most likely in association with p60, has an essential role in male meiotic spindle assembly and dissolution and the removal of midbody microtubules and, thus, cytokinesis. Katanin p80 also controls the formation, function, and dissolution of a microtubule structure intimately involved in defining sperm head shaping and sperm tail formation, the manchette, and plays a role in the formation of axoneme microtubules. Perturbed katanin p80 function, as evidenced in the Taily mouse, results in male sterility characterized by decreased sperm production, sperm with abnormal head shape, and a virtual absence of progressive motility. Collectively these data demonstrate that katanin p80 serves an essential and evolutionarily conserved role in several aspects of male germ cell development.
Assuntos
Adenosina Trifosfatases , Células Germinativas , Infertilidade Masculina/genética , Microtúbulos , Espermatogênese/genética , Espermatozoides , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Sequência de Aminoácidos , Animais , Astenozoospermia/genética , Expressão Gênica , Células Germinativas/citologia , Células Germinativas/metabolismo , Katanina , Masculino , Meiose/genética , Camundongos , Microtúbulos/genética , Microtúbulos/metabolismo , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Oligospermia/genética , Subunidades Proteicas/genética , Motilidade dos Espermatozoides/genética , Espermatozoides/citologia , Espermatozoides/metabolismo , Espermatozoides/patologia , Fuso Acromático/genética , Testículo/metabolismoRESUMO
Activated Th cells influence other T cells via positive feedback circuits that expand and polarize particular types of response, but little is known about how they may also initiate negative feedback against immunopathological reactions. In this study, we demonstrate the emergence, during chronic inflammation, of GATA-3(+) Th2 inhibitory (Th2i) cells that express high levels of inhibitory proteins including IL-10, CTLA-4, and granzyme B, but do so independently of Foxp3. Whereas other Th2 effectors promote proliferation and IL-4 production by naive T cells, Th2i cells suppress proliferation and IL-4 production. We show that Th2i cells develop directly from Th2 effectors, in a manner that can be promoted by effector cytokines including IL-2, IL-10, and IL-21 ex vivo and that requires T cell activation through CD28, Card11, and IL-2 in vivo. Formation of Th2i cells may act as an inbuilt activation-induced feedback inhibition mechanism against excessive or chronic Th2 responses.
Assuntos
Antígeno CTLA-4/biossíntese , Fatores de Transcrição Forkhead , Mediadores da Inflamação/fisiologia , Interleucina-10/biossíntese , Interleucina-2/fisiologia , Células Th2/imunologia , Animais , Antígeno CTLA-4/deficiência , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Células Cultivadas , Doença Crônica , Feminino , Fatores de Transcrição Forkhead/deficiência , Fatores de Transcrição Forkhead/fisiologia , Granzimas/biossíntese , Tolerância Imunológica/genética , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Células Th2/metabolismo , Células Th2/patologiaRESUMO
CD1d-dependent NKT cells represent a heterogeneous family of effector T cells including CD4(+)CD8(-) and CD4(-)CD8(-) subsets that respond to glycolipid Ags with rapid and potent cytokine production. NKT cell development is regulated by a unique combination of factors, however very little is known about factors that control the development of NKT subsets. In this study, we analyze a novel mouse strain (helpless) with a mis-sense mutation in the BTB-POZ domain of ZBTB7B and demonstrate that this mutation has dramatic, intrinsic effects on development of NKT cell subsets. Although NKT cell numbers are similar in Zbtb7b mutant mice, these cells are hyperproliferative and most lack CD4 and instead express CD8. Moreover, the majority of ZBTB7B mutant NKT cells in the thymus are retinoic acid-related orphan receptor γt positive, and a high frequency produce IL-17 while very few produce IFN-γ or other cytokines, sharply contrasting the profile of normal NKT cells. Mice heterozygous for the helpless mutation also have reduced numbers of CD4(+) NKT cells and increased production of IL-17 without an increase in CD8(+) cells, suggesting that ZBTB7B acts at multiple stages of NKT cell development. These results reveal ZBTB7B as a critical factor genetically predetermining the balance of effector subsets within the NKT cell population.
Assuntos
Antígenos CD1d/imunologia , Proteínas de Ligação a DNA/imunologia , Interleucina-17/imunologia , Mutação de Sentido Incorreto , Células T Matadoras Naturais/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/imunologia , Fatores de Transcrição/imunologia , Animais , Antígenos CD1d/genética , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Diferenciação Celular/imunologia , Proliferação de Células , Proteínas de Ligação a DNA/genética , Expressão Gênica/imunologia , Interferon gama/biossíntese , Interferon gama/imunologia , Interleucina-17/biossíntese , Masculino , Camundongos , Camundongos Transgênicos , Células T Matadoras Naturais/metabolismo , Células T Matadoras Naturais/patologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Estrutura Terciária de Proteína , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/patologia , Timo/imunologia , Timo/metabolismo , Timo/patologia , Fatores de Transcrição/genéticaRESUMO
Germinal centers (GCs) are specialized microenvironments formed after infection where activated B cells can mutate their B-cell receptors to undergo affinity maturation. A stringent process of selection allows high affinity, non-self-reactive B cells to become long-lived memory B cells and plasma cells. While the precise mechanism of selection is still poorly understood, the last decade has advanced our understanding of the role of T cells and follicular dendritic cells (FDCs) in GC B-cell formation and selection. T cells and non-T-cell-derived CD40 ligands on FDCs are essential for T-dependent (TD) and T-independent GC formation, respectively. TD-GC formation requires Bcl-6-expressing T cells capable of signaling through SAP, which promotes formation of stable T:B conjugates. By contrast, differentiation of B blasts along the extrafollicular pathway is less dependent on SAP. T-follicular helper (Tfh) cell-derived CD40L, interleukin-21, and interleukin-4 play important roles in GC B-cell proliferation, survival, and affinity maturation. A role for FDC-derived integrin signals has also emerged: GC B cells capable of forming an immune synapse with FDCs have a survival advantage. This emerges as a powerful mechanism to ensure death of B cells that bind self-reactive antigen, which would not normally be presented on FDCs.
Assuntos
Linfócitos B/imunologia , Células Dendríticas Foliculares/imunologia , Centro Germinativo/imunologia , Linfócitos T/imunologia , Animais , Linfócitos B/citologia , Sobrevivência Celular , Centro Germinativo/citologia , Humanos , Transdução de SinaisRESUMO
A subset of human follicular helper T cells (TFH) cells expresses CD57 for which no distinct function has been identified. We show that CD57+ TFH cells are universally PD-1hi, but compared to their CD57- PD-1hi counterparts, express little IL-21 or IL-10 among others. Instead, CD57 expression on TFH cells marks cytotoxicity transcriptional signatures that translate into only a weak cytotoxic phenotype. Similarly, circulating PD-1+ CD57+ CD4+ T cells make less cytokine than their CD57- PD-1+ counterparts, but have a prominent cytotoxic phenotype. By analysis of responses to STAT3-dependent cytokines and cells from patients with gain- or loss-of-function STAT3 mutations, we show that CD4+ T cell cytotoxicity is STAT3-dependent. TFH formation also requires STAT3, but paradoxically, once formed, PD-1hi cells become unresponsive to STAT3. These findings suggest that changes in blood and germinal center cytotoxicity might be affected by changes in STAT3 signaling, or modulation of PD-1 by therapy.
Assuntos
Antígenos CD57/imunologia , Regulação da Expressão Gênica/imunologia , Fator de Transcrição STAT3/imunologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Tonsilite/imunologia , Antígenos CD57/genética , Estudos de Casos e Controles , Proliferação de Células , Citotoxicidade Imunológica , Humanos , Imunofenotipagem , Interleucina-10/genética , Interleucina-10/imunologia , Interleucinas/genética , Interleucinas/imunologia , Tonsila Palatina/imunologia , Tonsila Palatina/patologia , Tonsila Palatina/cirurgia , Fenótipo , Cultura Primária de Células , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/imunologia , Fator de Transcrição STAT3/genética , Transdução de Sinais , Linfócitos T Citotóxicos/patologia , Linfócitos T Auxiliares-Indutores/patologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/patologia , Tonsilectomia , Tonsilite/genética , Tonsilite/patologia , Tonsilite/cirurgiaRESUMO
Type 1 (T1D) and type 2 (T2D) diabetes share pathophysiological characteristics, yet mechanistic links have remained elusive. T1D results from autoimmune destruction of pancreatic beta cells, whereas beta cell failure in T2D is delayed and progressive. Here we find a new genetic component of diabetes susceptibility in T1D non-obese diabetic (NOD) mice, identifying immune-independent beta cell fragility. Genetic variation in Xrcc4 and Glis3 alters the response of NOD beta cells to unfolded protein stress, enhancing the apoptotic and senescent fates. The same transcriptional relationships were observed in human islets, demonstrating the role of beta cell fragility in genetic predisposition to diabetes.
Assuntos
Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 2/genética , Predisposição Genética para Doença , Células Secretoras de Insulina/patologia , Animais , Apoptose , Senescência Celular , Proteínas de Ligação a DNA/genética , Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 2/patologia , Dieta , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Dobramento de Proteína , Proteínas Repressoras/genética , Fatores Sexuais , Estresse Fisiológico , Transativadores/genéticaRESUMO
A diversity of tools is available for identification of variants from genome sequence data. Given the current complexity of incorporating external software into a genome analysis infrastructure, a tendency exists to rely on the results from a single tool alone. The quality of the output variant calls is highly variable however, depending on factors such as sequence library quality as well as the choice of short-read aligner, variant caller, and variant caller filtering strategy. Here we present a two-part study first using the high quality 'genome in a bottle' reference set to demonstrate the significant impact the choice of aligner, variant caller, and variant caller filtering strategy has on overall variant call quality and further how certain variant callers outperform others with increased sample contamination, an important consideration when analyzing sequenced cancer samples. This analysis confirms previous work showing that combining variant calls of multiple tools results in the best quality resultant variant set, for either specificity or sensitivity, depending on whether the intersection or union, of all variant calls is used respectively. Second, we analyze a melanoma cell line derived from a control lymphocyte sample to determine whether software choices affect the detection of clinically important melanoma risk-factor variants finding that only one of the three such variants is unanimously detected under all conditions. Finally, we describe a cogent strategy for implementing a clinical variant detection pipeline; a strategy that requires careful software selection, variant caller filtering optimizing, and combined variant calls in order to effectively minimize false negative variants. While implementing such features represents an increase in complexity and computation the results offer indisputable improvements in data quality.
Assuntos
Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Linhagem Celular Tumoral , Simulação por Computador , Feminino , Humanos , Polimorfismo de Nucleotídeo Único/genética , Curva ROC , Fatores de Risco , SoftwareRESUMO
Studies on the biology of mucosal-associated invariant T cells (MAIT cells) in mice have been hampered by a lack of specific reagents. Using MR1-antigen (Ag) tetramers that specifically bind to the MR1-restricted MAIT T cell receptors (TCRs), we demonstrate that MAIT cells are detectable in a broad range of tissues in C57BL/6 and BALB/c mice. These cells include CD4(-)CD8(-), CD4(-)CD8(+), and CD4(+)CD8(-) subsets, and their frequency varies in a tissue- and strain-specific manner. Mouse MAIT cells have a CD44(hi)CD62L(lo) memory phenotype and produce high levels of IL-17A, whereas other cytokines, including IFN-γ, IL-4, IL-10, IL-13, and GM-CSF, are produced at low to moderate levels. Consistent with high IL-17A production, most MAIT cells express high levels of retinoic acid-related orphan receptor γt (RORγt), whereas RORγt(lo) MAIT cells predominantly express T-bet and produce IFN-γ. Most MAIT cells express the promyelocytic leukemia zinc finger (PLZF) transcription factor, and their development is largely PLZF dependent. These observations contrast with previous reports that MAIT cells from Vα19 TCR transgenic mice are PLZF(-) and express a naive CD44(lo) phenotype. Accordingly, MAIT cells from normal mice more closely resemble human MAIT cells than previously appreciated, and this provides the foundation for further investigations of these cells in health and disease.
Assuntos
Antígenos de Histocompatibilidade Classe I/metabolismo , Mucosa/imunologia , Células T Matadoras Naturais/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Animais , Proliferação de Células , Citocinas/metabolismo , Técnicas Histológicas , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Antígenos de Histocompatibilidade Menor , Mucosa/citologia , Células T Matadoras Naturais/citologia , Proteína com Dedos de Zinco da Leucemia Promielocítica , Especificidade da EspécieRESUMO
The generation of naïve T lymphocytes is critical for immune function yet the mechanisms governing their maturation remain incompletely understood. We have identified a mouse mutant, bloto, that harbors a hypomorphic mutation in the zinc finger protein Zfp335. Zfp335(bloto/bloto) mice exhibit a naïve T cell deficiency due to an intrinsic developmental defect that begins to manifest in the thymus and continues into the periphery, affecting T cells that have recently undergone thymic egress. The effects of Zfp335(bloto) are multigenic and cannot be attributed to altered thymic selection, proliferation or Bcl2-dependent survival. Zfp335 binds to promoter regions via a consensus motif, and its target genes are enriched in categories related to protein metabolism, mitochondrial function, and transcriptional regulation. Restoring the expression of one target, Ankle2, partially rescues T cell maturation. These findings identify Zfp335 as a transcription factor and essential regulator of late-stage intrathymic and post-thymic T cell maturation.
Assuntos
Proteínas de Membrana/genética , Mutação , Proteínas Nucleares/genética , Linfócitos T/metabolismo , Timo/metabolismo , Fatores de Transcrição/genética , Dedos de Zinco/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Diferenciação Celular , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Teste de Complementação Genética , Imunidade Inata , Proteínas de Membrana/imunologia , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos CBA , Camundongos Transgênicos , Dados de Sequência Molecular , Proteínas Nucleares/imunologia , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/imunologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Alinhamento de Sequência , Transdução de Sinais , Linfócitos T/imunologia , Linfócitos T/patologia , Timo/imunologia , Timo/patologia , Fatores de Transcrição/imunologia , Fatores de Transcrição/metabolismo , Transcrição Gênica , Dedos de Zinco/imunologiaRESUMO
The processes that normally generate and maintain adaptive immunity and immunological memory are poorly understood, and yet of fundamental importance when infectious diseases place such a major economic and social burden on the world's health and agriculture systems. Defects in these mechanisms also underlie the many forms of human primary immunodeficiency. Identifying these mechanisms in a systematic way is therefore important if we are to develop better strategies for treating and preventing infection, inherited disease, transplant rejection and autoimmunity. In this review we describe a genome-wide screen in mice for the genes important for generating these adaptive responses, and describe two independent DOCK8 mutant mice strains identified by this screen. DOCK 8 was found to play an essential role in humoral immune responses and to be important in the proper formation of the B cell immunological synapse.
Assuntos
Fatores de Troca do Nucleotídeo Guanina , Imunidade Humoral , Memória Imunológica , Animais , Anticorpos/imunologia , Linfócitos B/imunologia , Modelos Animais de Doenças , Etilnitrosoureia , Estudo de Associação Genômica Ampla , Centro Germinativo/imunologia , Centro Germinativo/patologia , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/imunologia , Síndromes de Imunodeficiência/imunologia , Síndromes de Imunodeficiência/patologia , Sinapses Imunológicas/imunologia , Sinapses Imunológicas/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MutaçãoRESUMO
During a screen for ethylnitrosourea-induced mutations in mice affecting blood natural killer (NK) cells, we identified a strain, designated Duane, in which NK cells were reduced in blood and spleen but increased in lymph nodes (LNs) and bone marrow (BM). The accumulation of NK cells in LNs reflected a decreased ability to exit into lymph. This strain carries a point mutation within Tbx21 (T-bet), which generates a defective protein. Duane NK cells have a 30-fold deficiency in sphingosine-1-phosphate receptor 5 (S1P5) transcript levels, and S1P5-deficient mice exhibit an egress defect similar to Duane. Chromatin immunoprecipitation confirms binding of T-bet to the S1pr5 locus. S1P-deficient mice exhibit a more severe NK cell egress block, and the FTY720-sensitive S1P1 also plays a role in NK cell egress from LNs. S1P5 is not inhibited by CD69, a property that may facilitate trafficking of activated NK cells to effector sites. Finally, the accumulation of NK cells within BM of S1P-deficient mice was associated with reduced numbers in BM sinusoids, suggesting a role for S1P in BM egress. In summary, these findings identify S1P5 as a T-bet-induced gene that is required for NK cell egress from LNs and BM.
Assuntos
Células da Medula Óssea/citologia , Movimento Celular , Células Matadoras Naturais/citologia , Células Matadoras Naturais/metabolismo , Linfonodos/citologia , Receptores de Lisoesfingolipídeo/metabolismo , Proteínas com Domínio T/metabolismo , Animais , Células da Medula Óssea/efeitos dos fármacos , Contagem de Células , Movimento Celular/efeitos dos fármacos , Etilnitrosoureia , Cloridrato de Fingolimode , Células Matadoras Naturais/efeitos dos fármacos , Linfonodos/efeitos dos fármacos , Ativação Linfocitária/efeitos dos fármacos , Lisofosfolipídeos/deficiência , Lisofosfolipídeos/farmacologia , Camundongos , Camundongos Mutantes , Mutação/genética , Propilenoglicóis/farmacologia , Esfingosina/análogos & derivados , Esfingosina/deficiência , Esfingosina/farmacologiaRESUMO
Coligation of CD21 with BCR on the surface of B cells provides a costimulatory signal essential for efficient Ab responses to T-dependent Ags. To achieve this, Ag must be directly linked to C3 fragments, but how this occurs in vivo is not fully understood. Using BCR transgenic mice, we demonstrated that C3 was deposited on the surface of B cells following both high- and moderate-affinity Ag binding. This was dependent on the specific binding of IgM to the BCR-bound Ag and can occur independently of soluble immune complex formation. Based on these data, we propose a novel model in which immune complexes can form directly on the surface of the B cell following Ag binding. This model has implications for our understanding of B lymphocyte activation.