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1.
Science ; 366(6470)2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31672916

RESUMO

Vaccine induction of broadly neutralizing antibodies (bnAbs) to HIV remains a major challenge. Germline-targeting immunogens hold promise for initiating the induction of certain bnAb classes; yet for most bnAbs, a strong dependence on antibody heavy chain complementarity-determining region 3 (HCDR3) is a major barrier. Exploiting ultradeep human antibody sequencing data, we identified a diverse set of potential antibody precursors for a bnAb with dominant HCDR3 contacts. We then developed HIV envelope trimer-based immunogens that primed responses from rare bnAb-precursor B cells in a mouse model and bound a range of potential bnAb-precursor human naïve B cells in ex vivo screens. Our repertoire-guided germline-targeting approach provides a framework for priming the induction of many HIV bnAbs and could be applied to most HCDR3-dominant antibodies from other pathogens.

2.
Sci Signal ; 12(604)2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31641080

RESUMO

Transitional B cells must actively undergo selection for self-tolerance before maturing into their resting follicular B cell successors. We found that metabolic quiescence was acquired at the follicular B cell stage in both humans and mice. In follicular B cells, the expression of genes involved in ribosome biogenesis, aerobic respiration, and mammalian target of rapamycin complex 1 (mTORC1) signaling was reduced when compared to that in transitional B cells. Functional metabolism studies, profiling of whole-cell metabolites, and analysis of cell surface proteins in human B cells suggested that this transition was also associated with increased extracellular adenosine salvage. Follicular B cells increased the abundance of the cell surface ectonucleotidase CD73, which coincided with adenosine 5'-monophosphate-activated protein kinase (AMPK) activation. Differentiation to the follicular B cell stage in vitro correlated with surface acquisition of CD73 on human transitional B cells and was augmented with the AMPK agonist, AICAR. Last, individuals with gain-of-function PIK3CD (PI3Kδ) mutations and increased pS6 activation exhibited a near absence of circulating follicular B cells. Together, our data suggest that mTORC1 attenuation may be necessary for human follicular B cell development. These data identify a distinct metabolic switch during human B cell development at the transitional to follicular stages, which is characterized by an induction of extracellular adenosine salvage, AMPK activation, and the acquisition of metabolic quiescence.

3.
Life Sci Alliance ; 1(5): e201800060, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30456377

RESUMO

During B-cell activation, the dynamic reorganisation of the cytoskeleton is crucial for multiple cellular responses, such as receptor signalling, cell spreading, antigen internalisation, intracellular trafficking, and antigen presentation. However, the role of intermediate filaments (IFs), which represent a major component of the mammalian cytoskeleton, is not well defined. Here, by using multiple super-resolution microscopy techniques, including direct stochastic optical reconstruction microscopy, we show that IFs in B cells undergo drastic reorganisation immediately upon antigen stimulation and that this reorganisation requires actin and microtubules. Although the loss of vimentin in B cells did not impair B-cell development, receptor signalling, and differentiation, vimentin-deficient B cells exhibit altered positioning of antigen-containing and lysosomal associated membrane protein 1 (LAMP1+) compartments, implying that vimentin may play a role in the fine-tuning of intracellular trafficking. Indeed, vimentin-deficient B cells exhibit impaired antigen presentation and delayed antibody responses in vivo. Thus, our study presents a new perspective on the role of IFs in B-cell activation.

4.
EMBO J ; 37(18)2018 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-30087111

RESUMO

Here, we describe a one-step, in vivo CRISPR/Cas9 nuclease-mediated strategy to generate knock-in mice. We produced knock-in (KI) mice wherein a 1.9-kb DNA fragment bearing a pre-arranged human B-cell receptor heavy chain was recombined into the native murine immunoglobulin locus. Our methodology relies on Cas9 nuclease-induced double-stranded breaks directed by two sgRNAs to occur within the specific target locus of fertilized oocytes. These double-stranded breaks are subsequently repaired via homology-directed repair by a plasmid-borne template containing the pre-arranged human immunoglobulin heavy chain. To validate our knock-in mouse model, we examined the expression of the KI immunoglobulin heavy chains by following B-cell development and performing single B-cell receptor sequencing. We optimized this strategy to generate immunoglobulin KI mice in a short amount of time with a high frequency of homologous recombination (30-50%). In the future, we envision that such knock-in mice will provide much needed vaccination models to evaluate immunoresponses against immunogens specific for various infectious diseases.


Assuntos
Linfócitos B/imunologia , Sistemas CRISPR-Cas , Técnicas de Introdução de Genes/métodos , Cadeias Pesadas de Imunoglobulinas , Animais , Linfócitos B/citologia , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/imunologia , Camundongos , Camundongos Transgênicos
5.
Cell Rep ; 24(3): 619-629, 2018 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-30021160

RESUMO

Wiskott-Aldrich syndrome protein (WASp) is a main cytoskeletal regulator in B cells. WASp-interacting protein (WIP) binds to and stabilizes WASp but also interacts with actin. Using mice with a mutated actin binding domain of WIP (WIPΔABD), we here investigated the role of WIP binding to actin during B cell activation. We found an altered differentiation of WIPΔABD B cells and diminished antibody affinity maturation after immunization. Mechanistically, WIPΔABD B cells showed impaired B cell receptor (BCR)-induced PI3K signaling and actin reorganization, likely caused by diminished CD81 expression and altered CD19 dynamics on the B cell surface. WIPΔABD B cells displayed reduced in vivo motility, concomitantly with impaired chemotaxis and defective F-actin polarization, HS1 phosphorylation, and polarization of HS1 to F-actin-rich structures after CXCL12 stimulation in vitro. We thus concluded that WIP binding to actin, independent of its binding to WASp, is critical for actin cytoskeleton plasticity in B cells.


Assuntos
Actinas/metabolismo , Linfócitos B/citologia , Linfócitos B/metabolismo , Movimento Celular , Imunidade Humoral , Animais , Afinidade de Anticorpos , Antígenos CD/metabolismo , Proteínas de Transporte/metabolismo , Membrana Celular/metabolismo , Polaridade Celular , Quimiotaxia , Proteínas do Citoesqueleto , Difusão , Centro Germinativo/metabolismo , Fator Estimulador de Colônias de Granulócitos/metabolismo , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Ligação Proteica , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais
6.
Immunity ; 48(6): 1144-1159.e5, 2018 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-29884460

RESUMO

PKCß-null (Prkcb-/-) mice are severely immunodeficient. Here we show that mice whose B cells lack PKCß failed to form germinal centers and plasma cells, which undermined affinity maturation and antibody production in response to immunization. Moreover, these mice failed to develop plasma cells in response to viral infection. At the cellular level, we have shown that Prkcb-/- B cells exhibited defective antigen polarization and mTORC1 signaling. While altered antigen polarization impaired antigen presentation and likely restricted the potential of GC development, defective mTORC1 signaling impaired metabolic reprogramming, mitochondrial remodeling, and heme biosynthesis in these cells, which altogether overwhelmingly opposed plasma cell differentiation. Taken together, our study reveals mechanistic insights into the function of PKCß as a key regulator of B cell polarity and metabolic reprogramming that instructs B cell fate.


Assuntos
Linfócitos B/imunologia , Diferenciação Celular/imunologia , Ativação Linfocitária/imunologia , Plasmócitos/imunologia , Proteína Quinase C beta/imunologia , Animais , Heme/biossíntese , Camundongos , Camundongos Knockout , Mitocôndrias/imunologia , Mitocôndrias/metabolismo , Plasmócitos/citologia
7.
Elife ; 72018 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-29337666

RESUMO

Wiskott-Aldrich syndrome (WAS) is an immune pathology associated with mutations in WAS protein (WASp) or in WASp interacting protein (WIP). Together with the small GTPase Cdc42 and other effectors, these proteins participate in the remodelling of the actin network downstream of BCR engagement. Here we show that mice lacking the adaptor protein ITSN2, a G-nucleotide exchange factor (GEF) for Cdc42 that also interacts with WASp and WIP, exhibited increased mortality during primary infection, incomplete protection after Flu vaccination, reduced germinal centre formation and impaired antibody responses to vaccination. These defects were found, at least in part, to be intrinsic to the B cell compartment. In vivo, ITSN2 deficient B cells show a reduction in the expression of SLAM, CD84 or ICOSL that correlates with a diminished ability to form long term conjugates with T cells, to proliferate in vivo, and to differentiate into germinal centre cells. In conclusion, our study not only revealed a key role for ITSN2 as an important regulator of adaptive immune-response during vaccination and viral infection but it is also likely to contribute to a better understanding of human immune pathologies.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Linfócitos B/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/patologia , Orthomyxoviridae/imunologia , Linfócitos T/imunologia , Proteínas Adaptadoras de Transporte Vesicular/deficiência , Animais , Adesão Celular , Proliferação de Células , Vacinas contra Influenza/administração & dosagem , Camundongos , Análise de Sobrevida
8.
Cell ; 172(3): 517-533.e20, 2018 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-29249358

RESUMO

B cells constitute an essential line of defense from pathogenic infections through the generation of class-switched antibody-secreting cells (ASCs) in germinal centers. Although this process is known to be regulated by follicular helper T (TfH) cells, the mechanism by which B cells initially seed germinal center reactions remains elusive. We found that NKT cells, a population of innate-like T lymphocytes, are critical for the induction of B cell immunity upon viral infection. The positioning of NKT cells at the interfollicular areas of lymph nodes facilitates both their direct priming by resident macrophages and the localized delivery of innate signals to antigen-experienced B cells. Indeed, NKT cells secrete an early wave of IL-4 and constitute up to 70% of the total IL-4-producing cells during the initial stages of infection. Importantly, the requirement of this innate immunity arm appears to be evolutionarily conserved because early NKT and IL-4 gene signatures also positively correlate with the levels of neutralizing antibodies in Zika-virus-infected macaques. In conclusion, our data support a model wherein a pre-TfH wave of IL-4 secreted by interfollicular NKT cells triggers the seeding of germinal center cells and serves as an innate link between viral infection and B cell immunity.


Assuntos
Linfócitos B/imunologia , Centro Germinativo/imunologia , Imunidade Inata , Influenza Humana/imunologia , Interleucina-4/genética , Células Matadoras Naturais/imunologia , Infecção por Zika virus/imunologia , Animais , Galinhas , Cães , Centro Germinativo/citologia , Humanos , Interleucina-4/metabolismo , Macaca , Macrófagos/imunologia , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos C57BL
10.
J Immunol ; 199(5): 1682-1695, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28747344

RESUMO

Rho family GTPases regulate diverse cellular events, such as cell motility, polarity, and vesicle traffic. Although a wealth of data exists on the canonical Rho GTPases RhoA, Rac1, and Cdc42, several other family members remain poorly studied. In B cells, we recently demonstrated a critical role for Cdc42 in plasma cell differentiation. In this study, we focus on a close homolog of Cdc42, TC10 (also known as RhoQ), and investigate its physiological role in B cells. By generating a TC10-deficient mouse model, we show that despite reduced total B cell numbers, B cell development in these mice occurs normally through distinct developmental stages. Upon immunization, IgM levels were reduced and, upon viral infection, germinal center responses were defective in TC10-deficient mice. BCR signaling was mildly affected, whereas cell migration remained normal in TC10-deficient B cells. Furthermore, by generating a TC10/Cdc42 double knockout mouse model, we found that TC10 can compensate for the lack of Cdc42 in TLR-induced cell activation and proliferation, so the two proteins play partly redundant roles. Taken together, by combining in vivo and in vitro analysis using TC10-deficient mice, we define the poorly studied Rho GTPase TC10 as an immunomodulatory molecule playing a role in physiological B cell responses.


Assuntos
Linfócitos B/imunologia , Infecções por Orthomyxoviridae/imunologia , Vaccinia/imunologia , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Animais , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Centro Germinativo/imunologia , Imunomodulação , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais , Proteína cdc42 de Ligação ao GTP/genética , Proteínas rho de Ligação ao GTP/genética
11.
J Exp Med ; 214(8): 2471-2490, 2017 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-28739603

RESUMO

Vaccines remain the most effective tool to prevent infectious diseases. Here, we introduce an in vitro booster vaccination approach that relies on antigen-dependent activation of human memory B cells in culture. This stimulation induces antigen-specific B cell proliferation, differentiation of B cells into plasma cells, and robust antibody secretion after a few days of culture. We validated this strategy using cells from healthy donors to retrieve human antibodies against tetanus toxoid and influenza hemagglutinin (HA) from H1N1 and newly emergent subtypes such as H5N1 and H7N9. Anti-HA antibodies were cross-reactive against multiple subtypes, and some showed neutralizing activity. Although these antibodies may have arisen as a result of previous influenza infection, we also obtained gp120-reactive antibodies from non-HIV-infected donors, indicating that we can generate antibodies without prior antigenic exposure. Overall, our novel approach can be used to rapidly produce therapeutic antibodies and has the potential to assess the immunogenicity of candidate antigens, which could be exploited in future vaccine development.

12.
Science ; 355(6325): 641-647, 2017 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-28183981

RESUMO

Autophagy is important in a variety of cellular and pathophysiological situations; however, its role in immune responses remains elusive. Here, we show that among B cells, germinal center (GC) cells exhibited the highest rate of autophagy during viral infection. In contrast to mechanistic target of rapamycin complex 1-dependent canonical autophagy, GC B cell autophagy occurred predominantly through a noncanonical pathway. B cell stimulation was sufficient to down-regulate canonical autophagy transiently while triggering noncanonical autophagy. Genetic ablation of WD repeat domain, phosphoinositide-interacting protein 2 in B cells alone enhanced this noncanonical autophagy, resulting in changes of mitochondrial homeostasis and alterations in GC and antibody-secreting cells. Thus, B cell activation prompts a temporal switch from canonical to noncanonical autophagy that is important in controlling B cell differentiation and fate.


Assuntos
Autofagia/imunologia , Linfócitos B/imunologia , Linfócitos B/virologia , Viroses/imunologia , Animais , Regulação para Baixo , Centro Germinativo/imunologia , Centro Germinativo/virologia , Ativação Linfocitária , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Mitocôndrias/metabolismo , Complexos Multiproteicos/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Repetições WD40/genética
13.
Eur J Immunol ; 46(11): 2520-2530, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27550373

RESUMO

The SH2 domain-containing inositol 5'-phosphatase (SHIP) plays a key role in preventing autoimmune phenomena by limiting antigen-mediated B cell activation. SHIP function is thought to require the dual engagement of the BCR and negative regulatory coreceptors as only the latter appear capable of recruiting SHIP from the cytosol to the plasma membrane by the virtue of phosphorylated immunoreceptor tyrosine-based inhibitory motifs. Here, we demonstrate a coreceptor-independent membrane recruitment and function of SHIP in B cells. In the absence of coreceptor ligation, SHIP translocates to sites of BCR activation through a concerted action of the protein adaptor unit Dok-3/Grb2 and phosphorylated BCR signaling components. Our data reveal auto-inhibitory SHIP activation by the activated BCR and suggest an unexpected negative-regulatory capacity of immunoreceptor tyrosine-based activation motifs in Igα and Igß.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteína Adaptadora GRB2/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Linfócitos B/imunologia , Linhagem Celular , Membrana Celular/química , Membrana Celular/genética , Membrana Celular/imunologia , Galinhas , Ativação Linfocitária , Camundongos , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/genética , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/imunologia , Fosforilação , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Transdução de Sinais
14.
Sci Signal ; 9(434): ra66, 2016 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-27353366

RESUMO

The adaptor molecule Cbl-interacting protein of 85 kD (CIN85) regulates signaling from a number of cell surface receptors, such as growth factor receptors and antigen receptors on lymphocytes. Because of its multidomain structure, CIN85 is thought to act as a classical adaptor protein that connects functionally distinct components of a given signaling pathway through diverse protein domains. However, we found that in B lymphocytes, CIN85 functions to oligomerize SLP-65, which is the central effector protein of the B cell receptor (BCR). Therefore, CIN85 trimerizes through a carboxyl-terminal, coiled-coil domain. The multiple Src homology 3 (SH3) domains of trimeric CIN85 molecules associated with multiple SLP-65 molecules, which recruited further CIN85 trimers, thereby perpetuating the oligomerization process. Formation of this oligomeric signaling complex in resting B cells rendered the cells poised for the efficient initiation of intracellular signaling upon BCR stimulation. Our data suggest that the functionality of signaling cascades does not rely solely on the qualitative linkage of their various components but requires a critical number of effectors to become concentrated in signaling complexes.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Linfócitos B/metabolismo , Ativação Linfocitária , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal/genética , Linhagem Celular , Humanos , Receptores de Antígenos de Linfócitos B/genética , Domínios de Homologia de src
15.
J Cell Biol ; 212(3): 267-80, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26833785

RESUMO

Recent evidence implicates the actin cytoskeleton in the control of receptor signaling. This may be of particular importance in the context of immune receptors, such as the B cell receptor, where dysregulated signaling can result in autoimmunity and malignancy. Here, we discuss the role of the actin cytoskeleton in controlling receptor compartmentalization, dynamics, and clustering as a means to regulate receptor signaling through controlling the interactions with protein partners. We propose that the actin cytoskeleton is a point of integration for receptor cross talk through modulation of protein dynamics and clustering. We discuss the implication of this cross talk via the cytoskeleton for both ligand-induced and low-level constitutive (tonic) signaling necessary for immune cell survival.


Assuntos
Citoesqueleto de Actina/metabolismo , Receptor Cross-Talk , Receptores de Superfície Celular/metabolismo , Receptores Imunológicos/metabolismo , Transdução de Sinais , Citoesqueleto de Actina/imunologia , Animais , Humanos , Transporte Proteico , Receptores de Superfície Celular/imunologia , Receptores Imunológicos/imunologia , Fatores de Tempo
16.
EMBO J ; 35(3): 258-80, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26671981

RESUMO

Receptor organization and dynamics at the cell membrane are important factors of signal transduction regulation. Using super-resolution microscopy and single-particle tracking, we show how the negative coreceptor CD22 works with the cortical cytoskeleton in restraining BCR signalling. In naïve B cells, we found endogenous CD22 to be highly mobile and organized into nanodomains. The landscape of CD22 and its lateral diffusion were perturbed either in the absence of CD45 or when the CD22 lectin domain was mutated. To understand how a relatively low number of CD22 molecules can keep BCR signalling in check, we generated Brownian dynamic simulations and supported them with ex vivo experiments. This combined approach suggests that the inhibitory function of CD22 is influenced by its nanoscale organization and is ensured by its fast diffusion enabling a "global BCR surveillance" at the plasma membrane.


Assuntos
Linfócitos B/fisiologia , Citoesqueleto/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Transdução de Sinais , Animais , Linfócitos B/citologia , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência
17.
Cell Rep ; 13(12): 2699-714, 2015 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-26711338

RESUMO

Cancer-associated fibroblasts (CAFs) are non-cancerous cells found in solid tumors that remodel the tumor matrix and promote cancer invasion and angiogenesis. Here, we demonstrate that Cdc42EP3/BORG2 is required for the matrix remodeling, invasion, angiogenesis, and tumor-growth-promoting abilities of CAFs. Cdc42EP3 functions by coordinating the actin and septin networks. Furthermore, depletion of SEPT2 has similar effects to those of loss of Cdc42EP3, indicating a role for the septin network in the tumor stroma. Cdc42EP3 is upregulated early in fibroblast activation and precedes the emergence of the highly contractile phenotype characteristic of CAFs. Depletion of Cdc42EP3 in normal fibroblasts prevents their activation by cancer cells. We propose that Cdc42EP3 sensitizes fibroblasts to further cues-in particular, those activating actomyosin contractility-and thereby enables the generation of the pathological activated fibroblast state.


Assuntos
Fibroblastos/metabolismo , Fibroblastos/patologia , Reguladores de Proteínas de Ligação ao GTP/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Septinas/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo , Animais , Linhagem Celular , Linhagem Celular Tumoral , Humanos , Camundongos , Regulação para Cima
18.
Immunity ; 43(4): 660-73, 2015 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-26453379

RESUMO

Humans with Wiskott-Aldrich syndrome display a progressive immunological disorder associated with compromised Wiskott-Aldrich Syndrome Interacting Protein (WIP) function. Mice deficient in WIP recapitulate such an immunodeficiency that has been attributed to T cell dysfunction; however, any contribution of B cells is as yet undefined. Here we have shown that WIP deficiency resulted in defects in B cell homing, chemotaxis, survival, and differentiation, ultimately leading to diminished germinal center formation and antibody production. Furthermore, in the absence of WIP, several receptors, namely the BCR, BAFFR, CXCR4, CXCR5, CD40, and TLR4, were impaired in promoting CD19 co-receptor activation and subsequent PI3 kinase (PI3K) signaling. The underlying mechanism was due to a distortion in the actin and tetraspanin networks that lead to altered CD19 cell surface dynamics. In conclusion, our findings suggest that, by regulating the cortical actin cytoskeleton, WIP influences the function of CD19 as a general hub for PI3K signaling.


Assuntos
Antígenos CD19/fisiologia , Linfócitos B/imunologia , Proteínas de Transporte/fisiologia , Fosfatidilinositol 3-Quinases/fisiologia , Transdução de Sinais/imunologia , Citoesqueleto de Actina/ultraestrutura , Actinas/análise , Animais , Formação de Anticorpos , Linfócitos B/efeitos dos fármacos , Linfócitos B/enzimologia , Linfócitos B/ultraestrutura , Proteínas de Transporte/genética , Células Cultivadas , Quimiocinas/farmacologia , Quimiocinas/fisiologia , Quimiotaxia/efeitos dos fármacos , Proteínas do Citoesqueleto , Centro Germinativo/imunologia , Centro Germinativo/patologia , Haptenos , Hemocianinas/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Linfopoese , Proteínas de Membrana/imunologia , Camundongos , Fosforilação , Plasmócitos/imunologia , Processamento de Proteína Pós-Traducional , Quimera por Radiação , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Quimiocinas/fisiologia , Tetraspaninas/análise , Vaccinia/imunologia , Vaccinia/patologia
19.
J Leukoc Biol ; 98(3): 301-11, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25995205

RESUMO

Understanding the molecular mechanisms regulating T cell reactivity is required for successful reprogramming of immune responses in medical conditions, characterized by dysfunctions of the immune system. Nck proteins are cytoplasmic adaptors mediating diverse cellular functions, including TCR signaling. By enhancing TCR signal strength, Nck proteins influence thymic selection and regulate the size and sensitivity of the peripheral T cell repertoire. Here, we investigated the contribution of Nck proteins to CD4(+) T cell differentiation and effector function using Nck.T(-/-) mice. Impaired GC formation and reduced Tfh were observed in Nck.T(-/-) mice after immunization with T cell-dependent antigens. Th2/Tfh-related cytokines, such as IL-4, IL-10, and IL-21, were decreased in Nck.T(-/-) mice T cells. Moreover, an increased susceptibility to cell death of Tfh cells in Nck.T(-/-) mice was associated with decreased levels of Akt phosphorylation. As a result of this dysregulation in Tfh cells of Nck.T(-/-) mice, we found impaired production and affinity maturation of antibodies against T cell-dependent antigens. Thus, Nck proteins not only participate in thymic selection and generation of the peripheral T cell repertoire but also are involved in the differentiation and effector functions of CD4(+) T cells.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Diferenciação Celular , Proteínas Oncogênicas/metabolismo , Linfócitos T Auxiliares-Indutores/citologia , Linfócitos T Auxiliares-Indutores/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Animais , Formação de Anticorpos , Apoptose , Citocinas/biossíntese , Deleção de Genes , Centro Germinativo/citologia , Humanos , Camundongos , Proteínas Oncogênicas/deficiência , Fatores de Transcrição/metabolismo
20.
Science ; 347(6222): 667-72, 2015 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-25657250

RESUMO

The layer of macrophages at the subcapsular sinus (SCS) captures pathogens entering the lymph node, preventing their global dissemination and triggering an immune response. However, how infection affects SCS macrophages remains largely unexplored. Here we show that infection and inflammation disrupt the organization of SCS macrophages in a manner that involves the migration of mature dendritic cells to the lymph node. This disrupted organization reduces the capacity of SCS macrophages to retain and present antigen in a subsequent secondary infection, resulting in diminished B cell responses. Thus, the SCS macrophage layer may act as a sensor or valve during infection to temporarily shut down the lymph node to further antigenic challenge. This shutdown may increase an organism's susceptibility to secondary infections.


Assuntos
Linfócitos B/imunologia , Movimento Celular/imunologia , Coinfecção/imunologia , Inflamação/imunologia , Macrófagos/imunologia , Infecções Cutâneas Estafilocócicas/imunologia , Staphylococcus aureus , Animais , Antígenos/imunologia , Linfócitos B/patologia , Células Dendríticas/imunologia , Linfonodos/imunologia , Linfonodos/patologia , Macrófagos/patologia , Camundongos , Camundongos Endogâmicos C57BL
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