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1.
J Hepatol ; 79(2): 296-313, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37224925

RESUMO

BACKGROUND & AIMS: The progression of non-alcoholic steatohepatitis (NASH) to fibrosis and hepatocellular carcinoma (HCC) is aggravated by auto-aggressive T cells. The gut-liver axis contributes to NASH, but the mechanisms involved and the consequences for NASH-induced fibrosis and liver cancer remain unknown. We investigated the role of gastrointestinal B cells in the development of NASH, fibrosis and NASH-induced HCC. METHODS: C57BL/6J wild-type (WT), B cell-deficient and different immunoglobulin-deficient or transgenic mice were fed distinct NASH-inducing diets or standard chow for 6 or 12 months, whereafter NASH, fibrosis, and NASH-induced HCC were assessed and analysed. Specific pathogen-free/germ-free WT and µMT mice (containing B cells only in the gastrointestinal tract) were fed a choline-deficient high-fat diet, and treated with an anti-CD20 antibody, whereafter NASH and fibrosis were assessed. Tissue biopsy samples from patients with simple steatosis, NASH and cirrhosis were analysed to correlate the secretion of immunoglobulins to clinicopathological features. Flow cytometry, immunohistochemistry and single-cell RNA-sequencing analysis were performed in liver and gastrointestinal tissue to characterise immune cells in mice and humans. RESULTS: Activated intestinal B cells were increased in mouse and human NASH samples and licensed metabolic T-cell activation to induce NASH independently of antigen specificity and gut microbiota. Genetic or therapeutic depletion of systemic or gastrointestinal B cells prevented or reverted NASH and liver fibrosis. IgA secretion was necessary for fibrosis induction by activating CD11b+CCR2+F4/80+CD11c-FCGR1+ hepatic myeloid cells through an IgA-FcR signalling axis. Similarly, patients with NASH had increased numbers of activated intestinal B cells; additionally, we observed a positive correlation between IgA levels and activated FcRg+ hepatic myeloid cells, as well the extent of liver fibrosis. CONCLUSIONS: Intestinal B cells and the IgA-FcR signalling axis represent potential therapeutic targets for the treatment of NASH. IMPACT AND IMPLICATIONS: There is currently no effective treatment for non-alcoholic steatohepatitis (NASH), which is associated with a substantial healthcare burden and is a growing risk factor for hepatocellular carcinoma (HCC). We have previously shown that NASH is an auto-aggressive condition aggravated, amongst others, by T cells. Therefore, we hypothesized that B cells might have a role in disease induction and progression. Our present work highlights that B cells have a dual role in NASH pathogenesis, being implicated in the activation of auto-aggressive T cells and the development of fibrosis via activation of monocyte-derived macrophages by secreted immunoglobulins (e.g., IgA). Furthermore, we show that the absence of B cells prevented HCC development. B cell-intrinsic signalling pathways, secreted immunoglobulins, and interactions of B cells with other immune cells are potential targets for combinatorial NASH therapies against inflammation and fibrosis.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Microbiota , Hepatopatia Gordurosa não Alcoólica , Humanos , Camundongos , Animais , Hepatopatia Gordurosa não Alcoólica/complicações , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/genética , Camundongos Endogâmicos C57BL , Fígado/patologia , Fibrose , Cirrose Hepática/complicações , Camundongos Transgênicos , Imunoglobulina A/metabolismo , Imunoglobulina A/farmacologia , Modelos Animais de Doenças , Dieta Hiperlipídica/efeitos adversos
2.
J Cell Sci ; 134(15)2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34342351

RESUMO

A better understanding of cell-cell and cell-niche interactions is crucial to comprehend the complexity of inflammatory or pathophysiological scenarios such as tissue damage during viral infections, the tumour microenvironment and neuroinflammation. Optical clearing and 3D volumetric imaging of large tissue pieces or whole organs is a rapidly developing methodology that holds great promise for the in-depth study of cells in their natural surroundings. These methods have mostly been applied to image structural components such as endothelial cells and neuronal architecture. Recent work now highlights the possibility of studying immune cells in detail within their respective immune niches. This Review summarizes recent developments in tissue clearing methods and 3D imaging, with a focus on the localization and quantification of immune cells. We first provide background to the optical challenges involved and their solutions before discussing published protocols for tissue clearing, the limitations of 3D imaging of immune cells and image analysis. Furthermore, we highlight possible applications for tissue clearing and propose future developments for the analysis of immune cells within homeostatic or inflammatory immune niches.


Assuntos
Células Endoteliais , Imageamento Tridimensional , Imagem Óptica , Microambiente Tumoral
3.
Proc Natl Acad Sci U S A ; 115(12): 3120-3125, 2018 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-29507226

RESUMO

The transcription factor Foxp1 is critical for early B cell development. Despite frequent deregulation of Foxp1 in B cell lymphoma, the physiological functions of Foxp1 in mature B cells remain unknown. Here, we used conditional gene targeting in the B cell lineage and report that Foxp1 disruption in developing and mature B cells results in reduced numbers and frequencies of follicular and B-1 B cells and in impaired antibody production upon T cell-independent immunization in vivo. Moreover, Foxp1-deficient B cells are impaired in survival even though they exhibit an increased capacity to proliferate. Transcriptional analysis identified defective expression of the prosurvival Bcl-2 family gene Bcl2l1 encoding Bcl-xl in Foxp1-deficient B cells, and we identified Foxp1 binding in the regulatory region of Bcl2l1 Transgenic overexpression of Bcl2 rescued the survival defect in Foxp1-deficient mature B cells in vivo and restored peripheral B cell numbers. Thus, our results identify Foxp1 as a physiological regulator of mature B cell survival mediated in part via the control of Bcl-xl expression and imply that this pathway might contribute to the pathogenic function of aberrant Foxp1 expression in lymphoma.


Assuntos
Linfócitos B/classificação , Linfócitos B/fisiologia , Fatores de Transcrição Forkhead/metabolismo , Proteínas Repressoras/metabolismo , Animais , Anticorpos/metabolismo , Antígenos CD19/metabolismo , Fatores de Transcrição Forkhead/genética , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Proteínas Repressoras/genética , Linfócitos T/fisiologia , Proteína bcl-X/genética , Proteína bcl-X/metabolismo
4.
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 , Vacínia/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
5.
Mucosal Immunol ; 17(1): 67-80, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37918715

RESUMO

Dysregulated B cell responses have been described in inflammatory bowel disease (IBD) patients; however, the role of B cells in IBD pathology remained incompletely understood. We here provide evidence for the detrimental role of activated B cells during the onset of autoimmune intestinal inflammation. Using Wiskott-Aldrich Syndrome interacting protein deficient (Wipf1-/-) mice as a mouse model of chronic colitis, we identified clusters of differentiation (CD)86 expression on activated B cells as a crucial factor exacerbating pro-inflammatory cytokine production of intestinal CD4 T cells. Depleting B cells through anti-CD20 antibody treatment or blocking costimulatory signals mediated by CD86 through cytotoxic T lymphocyte antigen-4-immunoglobulin (CTLA-4-Ig) diminished intestinal inflammation in our mouse model of chronic IBD at the onset of disease. This was due to a reduction in aberrant humoral immune responses and reduced CD4 T cell pro-inflammatory cytokine production, especially interferon-g (IFN-g) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Interestingly, in addition to B cells isolated from the inflamed colon of Wipf1-/- mice, we also found CD86 mRNA and protein expression upregulated on activated B cells isolated from inflamed tissue of human patients with IBD. B cell activation and CD86 expression were boosted by soluble CD40L in vitro, which we found in the serum of mice and human patients with IBD. In summary, our data provides detailed insight into the contribution of B cells to intestinal inflammation, with implications for the treatment of IBD.


Assuntos
Colite , Doenças Inflamatórias Intestinais , Humanos , Linfócitos T CD4-Positivos , Inflamação/metabolismo , Mucosa Intestinal , Intestinos/patologia
6.
J Exp Med ; 221(7)2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38722309

RESUMO

SYNTAXIN-11 (STX11) is a SNARE protein that mediates the fusion of cytotoxic granules with the plasma membrane at the immunological synapses of CD8 T or NK cells. Autosomal recessive inheritance of deleterious STX11 variants impairs cytotoxic granule exocytosis, causing familial hemophagocytic lymphohistiocytosis type 4 (FHL-4). In several FHL-4 patients, we also observed hypogammaglobulinemia, elevated frequencies of naive B cells, and increased double-negative DN2:DN1 B cell ratios, indicating a hitherto unrecognized role of STX11 in humoral immunity. Detailed analysis of Stx11-deficient mice revealed impaired CD4 T cell help for B cells, associated with disrupted germinal center formation, reduced isotype class switching, and low antibody avidity. Mechanistically, Stx11-/- CD4 T cells exhibit impaired membrane fusion leading to reduced CD107a and CD40L surface mobilization and diminished IL-2 and IL-10 secretion. Our findings highlight a critical role of STX11 in SNARE-mediated membrane trafficking and vesicle exocytosis in CD4 T cells, important for successful CD4 T cell-B cell interactions. Deficiency in STX11 impairs CD4 T cell-dependent B cell differentiation and humoral responses.


Assuntos
Linfócitos B , Linfócitos T CD4-Positivos , Proteínas Qa-SNARE , Animais , Proteínas Qa-SNARE/metabolismo , Proteínas Qa-SNARE/genética , Linfócitos B/imunologia , Linfócitos B/metabolismo , Camundongos , Humanos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfo-Histiocitose Hemofagocítica/imunologia , Linfo-Histiocitose Hemofagocítica/genética , Linfo-Histiocitose Hemofagocítica/metabolismo , Camundongos Knockout , Camundongos Endogâmicos C57BL , Feminino , Masculino , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Imunidade Humoral , Exocitose
7.
Npj Imaging ; 1(1): 3, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38665236

RESUMO

Conventional histology, as well as immunohistochemistry or immunofluorescence, enables the study of morphological and phenotypical changes during tissue inflammation with single-cell accuracy. However, although highly specific, such techniques require multiple time-consuming steps to apply exogenous labels, which might result in morphological deviations from native tissue structures. Unlike these techniques, mid-infrared (mid-IR) microspectroscopy is a label-free optical imaging method that retrieves endogenous biomolecular contrast without altering the native composition of the samples. Nevertheless, due to the strong optical absorption of water in biological tissues, conventional mid-IR microspectroscopy has been limited to dried thin (5-10 µm) tissue preparations and, thus, it also requires time-consuming steps-comparable to conventional imaging techniques. Here, as a step towards label-free analytical histology of unprocessed tissues, we applied mid-IR optoacoustic microscopy (MiROM) to retrieve intrinsic molecular contrast by vibrational excitation and, simultaneously, to overcome water-tissue opacity of conventional mid-IR imaging in thick (mm range) tissues. In this proof-of-concept study, we demonstrated application of MiROM for the fast, label-free, non-destructive assessment of the hallmarks of inflammation in excised white adipose tissue; i.e., formation of crown-like structures and changes in adipocyte morphology.

8.
Eur J Immunol ; 41(11): 3176-86, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21830209

RESUMO

The relevance of direct inflammatory signals (signal 3) for the activation of memory CD8(+) T cells during recall responses is so far unknown. We therefore investigated the direct impact of IL-12 and type I IFN on the formation, recall potential and protective capacity of memory T cells. Using CD8(+) T cells deficient for IL-12 or type I IFN receptors in an adoptive transfer system, we generated memory populations after infection with vaccinia virus, lymphocytic choriomeningitis virus or Listeria monocytogenes. The results demonstrate that in the absence of signal 3 cytokines during primary infection, functional memory T cells were formed. After retransfer into naïve mice, signal 3-deficient memory T cells were able to specifically lyse target cells in vivo under non-infectious conditions. However, after reinfection, secondary effector CD8(+) T cells lacking signal 3 were impaired in expansion and protective capacity dependent on the nature of the pathogen. We conclude that memory CD8(+) T cells depend on a signal 3 for expansion, independent of signals obtained during priming, thereby being influenced by the pathogen-induced inflammatory milieu during secondary infection. In summary, our results reveal an essential role for direct inflammatory cytokine signaling in secondary T-cell responses.


Assuntos
Infecções por Arenaviridae/imunologia , Linfócitos T CD8-Positivos/imunologia , Memória Imunológica/imunologia , Listeriose/imunologia , Ativação Linfocitária/imunologia , Transdução de Sinais/imunologia , Vacínia/imunologia , Animais , Separação Celular , Citocinas/biossíntese , Citocinas/imunologia , Citometria de Fluxo , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL
9.
Int J Radiat Oncol Biol Phys ; 112(3): 747-758, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-34619330

RESUMO

PURPOSE: Radiation-induced cognitive deficits have a severe negative impact on pediatric brain tumor patients. The severity of cognitive symptoms is related to the age of the child when radiation was applied, with the most severe effects seen in the youngest. Previous studies using whole-brain irradiation in mice confirmed these findings. To understand ipsilateral and contralateral changes in the hippocampus after partial-brain radiation therapy (PBRT) of the left hemisphere, we assessed the neuroplasticity and changes in the microvasculature of the irradiated and nonirradiated hippocampus in juvenile mice. METHODS AND MATERIALS: The left hemispheres of 5-week-old mice were irradiated with 2, 8, and 20 Gy and a fractionated dose of 8 Gy in 2 fractions using a computed tomography image guided small animal radiation research platform. Long-term potentiation (LTP) has been monitored ex vivo in the hippocampal cornu ammonis 1 (CA1) region and was assessed 3 days and 5 and 10 weeks after PBRT in both hemispheres and compared to a sham group. Irradiation effects on the hippocampus microvasculature were quantified by efficient tissue clearing and multiorgan volumetric imaging. RESULTS: LTP in irradiated hippocampal slices of juvenile mice declines 3 days after radiation, lasts up to 10 weeks in the irradiated part of the hippocampus, and correlates with a significantly reduced microvasculature length. Specifically, LTP inhibition is sustained in the irradiated (20 Gy, 8 Gy in 2 fractions, 8 Gy, 2 Gy) hippocampus, whereas the contralateral hippocampus remains unaffected after PBRT. LTP inhibition in the irradiated hemisphere after PBRT might be associated with an impaired microvascular network. CONCLUSION: PBRT induces a long-lasting impairment in neuroplasticity and the microvessel network of the irradiated hippocampus, whereas the contralateral hippocampus remains unaffected. These findings provide insight into the design of PBRT strategies to better protect the young developing brain from cognitive decline.


Assuntos
Disfunção Cognitiva , Hipocampo , Animais , Encéfalo , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/etiologia , Hipocampo/diagnóstico por imagem , Hipocampo/patologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Plasticidade Neuronal/efeitos da radiação
10.
Eur J Immunol ; 40(12): 3450-7, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21080375

RESUMO

Trogocytosis describes the transfer of surface determinants between immune cells and has been implicated in immune regulation. Most findings are based on in vitro studies since in vivo trogocytosis of immune cells is difficult to detect under physiological conditions. We used low frequencies of memory P14 T cells to demonstrate that T cells perform trogocytosis in vivo if in contact with APC pulsed with GP33-peptide or expressing the antigen endogenously. Furthermore, in vivo trogocytosis of T cells is demonstrated during infections with lymphocytic choriomeningitis virus and vaccinia virus. Trogocytosis-positive T cells revealed higher expression of activation marker and cytokines, showing a more activated phenotype compared to trogocytosis-negative T cells.


Assuntos
Células Apresentadoras de Antígenos/metabolismo , Infecções por Arenaviridae/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Fusão de Membrana , Linfócitos T/metabolismo , Transferência Adotiva , Animais , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/patologia , Antígenos de Superfície/metabolismo , Antígenos Virais/imunologia , Células Cultivadas , Glicoproteínas/imunologia , Ativação Linfocitária , Vírus da Coriomeningite Linfocítica/patogenicidade , Fusão de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fragmentos de Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T/genética , Linfócitos T/imunologia , Linfócitos T/patologia , Linfócitos T/virologia , Proteínas Virais/imunologia
11.
Front Immunol ; 12: 670290, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33936114

RESUMO

Humoral immunity is mainly mediated by a B cell population highly specialized to synthesize and secrete large quantities of antibodies - the antibody-secreting cells (ASC). In the gastrointestinal environment, a mixture of foreign antigens from the diet, commensal microbiota as well as occasional harmful pathogens lead to a constant differentiation of B cells into ASC. Due to this permanent immune response, more than 80% of mammalian ASC reside in the gut, of which most express immunoglobulin A (IgA). IgA antibodies contribute to intestinal homeostasis and can mediate protective immunity. Recent evidence points at a role for gut-derived ASC in modulating immune responses also outside of mucosal tissues. We here summarize recent evidence for wandering ASC, their antibodies and their involvement in systemic immune responses.


Assuntos
Imunidade Humoral/imunologia , Imunidade nas Mucosas/imunologia , Imunoglobulina A/imunologia , Mucosa Intestinal/imunologia , Plasmócitos/imunologia , Animais , Quimiotaxia de Leucócito/imunologia , Humanos
12.
Eur J Immunol ; 39(7): 1774-83, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19548244

RESUMO

To study the role of IL-12 as a third signal for T-cell activation and differentiation in vivo, direct IL-12 signaling to CD8(+) T cells was analyzed in bacterial and viral infections using the P14 T-cell adoptive transfer model with CD8(+) T cells that lack the IL-12 receptor. Results indicate that CD8(+) T cells deficient in IL-12 signaling were impaired in clonal expansion after Listeria monocytogenes infection but not after infection with lymphocytic choriomeningitis virus, vaccinia virus or vesicular stomatitis virus. Although limited in clonal expansion after Listeria infection, CD8(+) T cells deficient in IL-12 signaling exhibited normal degranulation activity, cytolytic functions, and secretion of IFN-gamma and TNF-alpha. However, CD8(+) T cells lacking IL-12 signaling failed to up-regulate KLRG1 and to down-regulate CD127 in the context of Listeria but not viral infections. Thus, direct IL-12 signaling to CD8(+) T cells determines the cell fate decision between short-lived effector cells and memory precursor effector cells, which is dependent on pathogen-induced local cytokine milieu.


Assuntos
Diferenciação Celular/imunologia , Listeriose/imunologia , Coriomeningite Linfocítica/imunologia , Linfócitos T/citologia , Transferência Adotiva/métodos , Animais , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/microbiologia , Linfócitos T CD8-Positivos/virologia , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células , Citometria de Fluxo , Memória Imunológica/imunologia , Interferon gama/imunologia , Subunidade alfa de Receptor de Interleucina-7/imunologia , Lectinas Tipo C , Listeriose/microbiologia , Listeriose/terapia , Coriomeningite Linfocítica/virologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores Imunológicos/imunologia , Receptores de Interleucina-12/deficiência , Receptores de Interleucina-12/genética , Receptores de Interleucina-12/imunologia , Transdução de Sinais/imunologia , Linfócitos T/microbiologia , Linfócitos T/virologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/imunologia
13.
Front Immunol ; 11: 599495, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33569052

RESUMO

Spatial information of cells in their tissue microenvironment is necessary to understand the complexity of pathophysiological processes. Volumetric imaging of cleared organs provides this information; however, current protocols are often elaborate, expensive, and organ specific. We developed a simplified, cost-effective, non-hazardous approach for efficient tissue clearing and multi-organ volumetric imaging (EMOVI). EMOVI enabled multiplexed antibody-based immunolabeling, provided adequate tissue transparency, maintained cellular morphology and preserved fluorochromes. Exemplarily, EMOVI allowed the detection and quantification of scarce cell populations during pneumonitis. EMOVI also permitted histo-cytometric analysis of MHC-II expressing cells, revealing distinct populations surrounding or infiltrating glomeruli of nephritic kidneys. Using EMOVI, we found widefield microscopy with real-time computational clearing as a valuable option for rapid image acquisition and detection of rare cellular events in cleared organs. EMOVI has the potential to make tissue clearing and volumetric imaging of immune cells applicable for a broad audience by facilitating flexibility in organ, fluorochrome and microscopy usage.


Assuntos
Imageamento Tridimensional , Glomérulos Renais , Animais , Inflamação/imunologia , Inflamação/patologia , Glomérulos Renais/imunologia , Glomérulos Renais/patologia , Camundongos , Microscopia Confocal , Nefrite/imunologia , Nefrite/patologia
15.
Front Immunol ; 9: 699, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29713321

RESUMO

Conventional dendritic cells (cDCs) are versatile activators of immune responses that develop as part of the myeloid lineage downstream of hematopoietic stem cells. We have recently shown that in mice precursors of cDCs, but not of other leukocytes, are marked by expression of DNGR-1/CLEC9A. To genetically deplete DNGR-1-expressing cDC precursors and their progeny, we crossed Clec9a-Cre mice to Rosa-lox-STOP-lox-diphtheria toxin (DTA) mice. These mice develop signs of age-dependent myeloproliferative disease, as has been observed in other DC-deficient mouse models. However, despite efficient depletion of cDC progenitors in these mice, cells with phenotypic characteristics of cDCs populate the spleen. These cells are functionally and transcriptionally similar to cDCs in wild type control mice but show somatic rearrangements of Ig-heavy chain genes, characteristic of lymphoid origin cells. Our studies reveal a previously unappreciated developmental heterogeneity of cDCs and suggest that the lymphoid lineage can generate cells with features of cDCs when myeloid cDC progenitors are impaired.


Assuntos
Células Dendríticas/imunologia , Lectinas Tipo C/imunologia , Receptores Imunológicos/imunologia , Animais , Células Dendríticas/efeitos dos fármacos , Toxina Diftérica/farmacologia , Lectinas Tipo C/genética , Camundongos , Receptores Imunológicos/genética
16.
J Exp Med ; 212(1): 53-72, 2015 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-25547673

RESUMO

The small Rho GTPase Cdc42, known to interact with Wiskott-Aldrich syndrome (WAS) protein, is an important regulator of actin remodeling. Here, we show that genetic ablation of Cdc42 exclusively in the B cell lineage is sufficient to render mice unable to mount antibody responses. Indeed Cdc42-deficient mice are incapable of forming germinal centers or generating plasma B cells upon either viral infection or immunization. Such severe immune deficiency is caused by multiple and profound B cell abnormalities, including early blocks during B cell development; impaired antigen-driven BCR signaling and actin remodeling; defective antigen presentation and in vivo interaction with T cells; and a severe B cell-intrinsic block in plasma cell differentiation. Thus, our study presents a new perspective on Cdc42 as key regulator of B cell physiology.


Assuntos
Linfócitos B/imunologia , Diferenciação Celular/imunologia , Imunidade Humoral/imunologia , Infecções por Orthomyxoviridae/imunologia , Proteína cdc42 de Ligação ao GTP/imunologia , Animais , Formação de Anticorpos/imunologia , Linfócitos B/metabolismo , Linfócitos B/ultraestrutura , Células da Medula Óssea/imunologia , Células da Medula Óssea/metabolismo , Diferenciação Celular/genética , Células Cultivadas , Citometria de Fluxo , Expressão Gênica/imunologia , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Imunidade Humoral/genética , Vírus da Influenza A/imunologia , Tecido Linfoide/imunologia , Tecido Linfoide/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia Confocal , Microscopia Eletrônica , Infecções por Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína cdc42 de Ligação ao GTP/genética , Proteína cdc42 de Ligação ao GTP/metabolismo
17.
Cell Microbiol ; 9(2): 502-13, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16978234

RESUMO

Bacillus anthracis is a sporulating Gram-positive bacterium that causes the disease anthrax. The highly stable spore is the infectious form of the bacterium that first interacts with the prospective host, and thus the interaction between the host and spore is vital to the development of disease. We focused our study on the response of murine splenocytes to the B. anthracis spore by using paraformaldehyde-inactivated spores (FIS), a treatment that prevents germination and production of products associated with vegetative bacilli. We found that murine splenocytes produce IL-12 and IFN-gamma in response to FIS. The IL-12 was secreted by CD11b cells, which functioned to induce the production of IFN-gamma by CD49b (DX5) NK cells. The production of these cytokines by splenocytes was not dependent on TLR2, TLR4, TLR9, Nod1, or Nod2; however, it was dependent on the signalling adapter protein MyD88. Unlike splenocytes, Nod1- and Nod2-transfected HEK cells were activated by FIS. Both IL-12 and IFN-gamma secretion were inhibited by treatment with B. anthracis lethal toxin. These observations suggest that the innate immune system recognizes spores with a MyD88-dependent receptor (or receptors) and responds by secreting inflammatory cytokines, which may ultimately aid in resisting infection.


Assuntos
Bacillus anthracis/fisiologia , Citocinas/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Receptores Imunológicos/metabolismo , Transdução de Sinais , Baço/citologia , Esporos Bacterianos/imunologia , Animais , Linhagem Celular , Citocinas/genética , Humanos , Camundongos , Fator 88 de Diferenciação Mieloide/imunologia
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