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1.
Nat Immunol ; 14(6): 633-43, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23624555

RESUMO

The differentiation of hematopoietic stem cells into cells of the immune system has been studied extensively in mammals, but the transcriptional circuitry that controls it is still only partially understood. Here, the Immunological Genome Project gene-expression profiles across mouse immune lineages allowed us to systematically analyze these circuits. To analyze this data set we developed Ontogenet, an algorithm for reconstructing lineage-specific regulation from gene-expression profiles across lineages. Using Ontogenet, we found differentiation stage-specific regulators of mouse hematopoiesis and identified many known hematopoietic regulators and 175 previously unknown candidate regulators, as well as their target genes and the cell types in which they act. Among the previously unknown regulators, we emphasize the role of ETV5 in the differentiation of γδ T cells. As the transcriptional programs of human and mouse cells are highly conserved, it is likely that many lessons learned from the mouse model apply to humans.


Assuntos
Algoritmos , Regulação da Expressão Gênica/imunologia , Sistema Imunitário/metabolismo , Transcrição Gênica/imunologia , Animais , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Linhagem da Célula/genética , Linhagem da Célula/imunologia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/imunologia , Perfilação da Expressão Gênica , Redes Reguladoras de Genes/imunologia , Humanos , Sistema Imunitário/citologia , Camundongos , Análise de Sequência com Séries de Oligonucleotídeos , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Transativadores/genética , Transativadores/imunologia , Fatores de Transcrição/genética , Fatores de Transcrição/imunologia , Transcriptoma/genética , Transcriptoma/imunologia
2.
Nat Immunol ; 14(6): 619-32, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23644507

RESUMO

The differentiation of αßT cells from thymic precursors is a complex process essential for adaptive immunity. Here we exploited the breadth of expression data sets from the Immunological Genome Project to analyze how the differentiation of thymic precursors gives rise to mature T cell transcriptomes. We found that early T cell commitment was driven by unexpectedly gradual changes. In contrast, transit through the CD4(+)CD8(+) stage involved a global shutdown of housekeeping genes that is rare among cells of the immune system and correlated tightly with expression of the transcription factor c-Myc. Selection driven by major histocompatibility complex (MHC) molecules promoted a large-scale transcriptional reactivation. We identified distinct signatures that marked cells destined for positive selection versus apoptotic deletion. Differences in the expression of unexpectedly few genes accompanied commitment to the CD4(+) or CD8(+) lineage, a similarity that carried through to peripheral T cells and their activation, demonstrated by mass cytometry phosphoproteomics. The transcripts newly identified as encoding candidate mediators of key transitions help define the 'known unknowns' of thymocyte differentiation.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Animais , Antígenos CD/imunologia , Antígenos CD/metabolismo , Antígenos de Diferenciação de Linfócitos T/imunologia , Antígenos de Diferenciação de Linfócitos T/metabolismo , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular/genética , Linhagem da Célula/genética , Linhagem da Célula/imunologia , Proliferação de Células , Células Cultivadas , Análise por Conglomerados , Citometria de Fluxo , Antígenos de Histocompatibilidade/genética , Antígenos de Histocompatibilidade/imunologia , Antígenos de Histocompatibilidade/metabolismo , Lectinas Tipo C/imunologia , Lectinas Tipo C/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Timócitos/citologia , Timócitos/imunologia , Timócitos/metabolismo , Transcriptoma/genética , Transcriptoma/imunologia
3.
J Immunol ; 201(2): 804-813, 2018 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-29898964

RESUMO

In mice, fetal/neonatal B-1 cell development generates murine CD5+ B cells (B1a) with autoreactivity. We analyzed B1a cells at the neonatal stage in a VH11/D/JH knock-in mouse line (VH11t) that generates an autoreactive antiphosphatidylcholine BCR. Our study revealed that antiphosphatidylcholine B1a cells develop in liver, mature in spleen, and distribute in intestine/colon, mesenteric lymph node (mLN), and body cavity as the outcome of B-1 cell development before B-2 cell development. Throughout life, self-renewing B-1 B1a cells circulate through intestine, mesenteric vessel, and blood. The body cavity-deposited B1a cells also remigrate. In old age, some B1a cells proceed to monoclonal B cell lymphocytosis. When neonatal B-1 B1a cells express an antithymocyte/Thy-1 autoreactivity (ATA) BCR transgene in the C.B17 mouse background, ATA B cells increase in PBL and strongly develop lymphomas in aging mice that feature splenomegaly and mLN hyperplasia with heightened expression of CD11b, IL-10, and activated Stat3. At the adult stage, ATA B cells were normally present in the mantle zone area, including in intestine. Furthermore, frequent association with mLN hyperplasia suggests the influence by intestinal microenvironment on lymphoma development. When cyclin D1 was overexpressed by the Eµ-cyclin D1 transgene, ATA B cells progressed to further diffused lymphoma in aged mice, including in various lymph nodes with accumulation of IgMhiIgDloCD5+CD23-CD43+ cells, resembling aggressive human mantle cell lymphoma. Thus, our findings reveal that early generated B cells, as an outcome of B-1 cell development, can progress to become lymphocytosis, lymphoma, and mantle cell lymphoma-like neoplasia in aged mice.


Assuntos
Envelhecimento/imunologia , Linfócitos B/patologia , Linfoma de Célula do Manto/imunologia , Envelhecimento/patologia , Animais , Autoantígenos/imunologia , Carcinogênese , Diferenciação Celular , Ciclina D1/genética , Ciclina D1/metabolismo , Técnicas de Introdução de Genes , Linfoma de Célula do Manto/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fosfatidilcolinas/imunologia , Receptores de Antígenos de Linfócitos B/genética , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo
4.
J Immunol ; 199(5): 1706-1715, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28739882

RESUMO

CD79a and CD79b proteins associate with Ig receptors as integral signaling components of the B cell Ag receptor complex. To study B cell development in zebrafish, we isolated orthologs of these genes and performed in situ hybridization, finding that their expression colocalized with IgH-µ in the kidney, which is the site of B cell development. CD79 transgenic lines were made by linking the promoter and upstream regulatory segments of CD79a and CD79b to enhanced GFP to identify B cells, as demonstrated by PCR analysis of IgH-µ expression in sorted cells. We crossed these CD79-GFP lines to a recombination activating gene (Rag)2:mCherry transgenic line to identify B cell development stages in kidney marrow. Initiation of CD79:GFP expression in Rag2:mCherry+ cells and the timing of Ig H and L chain expression revealed simultaneous expression of both IgH-µ- and IgL-κ-chains, without progressing through the stage of IgH-µ-chain alone. Rag2:mCherry+ cells without CD79:GFP showed the highest Rag1 and Rag2 mRNAs compared with CD79a and CD79b:GFP+ B cells, which showed strongly reduced Rag mRNAs. Thus, B cell development in zebrafish does not go through a Raghi CD79+IgH-µ+ pre-B cell stage, different from mammals. After the generation of CD79:GFP+ B cells, decreased CD79 expression occurred upon differentiation to Ig secretion, as detected by alteration from membrane to secreted IgH-µ exon usage, similar to in mammals. This confirmed a conserved role for CD79 in B cell development and differentiation, without the requirement of a pre-B cell stage in zebrafish.


Assuntos
Linfócitos B/fisiologia , Antígenos CD79/metabolismo , Proteínas de Peixes/metabolismo , Rim/fisiologia , Células Precursoras de Linfócitos B/fisiologia , Peixe-Zebra/imunologia , Animais , Animais Geneticamente Modificados , Antígenos CD79/genética , Diferenciação Celular , Clonagem Molecular , Proteínas de Ligação a DNA/genética , Proteínas de Peixes/genética , Genes Reporter/genética , Proteínas de Fluorescência Verde/genética , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/metabolismo , Cadeias Leves de Imunoglobulina/genética , Cadeias Leves de Imunoglobulina/metabolismo , Ativação Linfocitária , Transgenes/genética , Proteínas de Peixe-Zebra/genética
6.
J Immunol ; 194(2): 606-14, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25480561

RESUMO

Expression of a germline VH3609/D/JH2 IgH in mice results in the generation of B1 B cells with anti-thymocyte/Thy-1 glycoprotein autoreactivity by coexpression of Vk21-5/Jk2 L chain leading to production of serum IgM natural autoantibody. In these same mice, the marginal zone (MZ) B cell subset in spleen shows biased usage of a set of Ig L chains different from B1 B cells, with 30% having an identical Vk19-17/Jk1 L chain rearrangement. This VH3609/Vk19-17 IgM is reactive with intestinal goblet cell granules, binding to the intact large polymatrix form of mucin 2 glycoprotein secreted by goblet cells. Analysis of a µκ B cell AgR (BCR) transgenic (Tg) mouse with this anti-goblet cell/mucin2 autoreactive (AGcA) specificity demonstrates that immature B cells expressing the Tg BCR become MZ B cells in spleen by T cell-independent BCR signaling. These Tg B cells produce AGcA as the predominant serum IgM, but without enteropathy. Without the transgene, AGcA autoreactivity is low but detectable in the serum of BALB/c and C.B17 mice, and this autoantibody is specifically produced by the MZ B cell subset. Thus, our findings reveal that AGcA is a natural autoantibody associated with MZ B cells.


Assuntos
Autoanticorpos/imunologia , Subpopulações de Linfócitos B/imunologia , Células Caliciformes/imunologia , Mucina-2/imunologia , Receptores de Antígenos de Linfócitos B/imunologia , Vesículas Secretórias/imunologia , Animais , Autoanticorpos/genética , Subpopulações de Linfócitos B/patologia , Células Caliciformes/patologia , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/imunologia , Imunoglobulina M/genética , Imunoglobulina M/imunologia , Cadeias kappa de Imunoglobulina/genética , Cadeias kappa de Imunoglobulina/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Mucina-2/genética , Receptores de Antígenos de Linfócitos B/genética , Vesículas Secretórias/genética , Vesículas Secretórias/patologia , Baço/imunologia , Baço/patologia
7.
Eur J Immunol ; 45(11): 2978-84, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26339791

RESUMO

CD5(+) B-cell origins and their predisposition to lymphoma are long-standing issues. Transfer of fetal and adult liver BM Pro-B cells generates B cells with distinct phenotypes: fetal cells generate IgM(high) IgD(low) CD5(+) , whereas adult cells IgM(low) IgD(high) CD5(-) . This suggests a developmental switch in B lymphopoiesis, similar to the switch in erythropoiesis. Comparison of mRNA and miRNA expression in fetal and adult Pro-B cells revealed differential expression of Lin28b mRNA and Let-7 miRNA, providing evidence that this regulatory axis functions in the switch. Recent work has shown that Arid3a is a key transcription factor mediating fetal-type B-cell development. Lin28b-promoted fetal development generates CD5(+) B cells as a consequence of positively selected self-reactivity. CD5(+) B cells play important roles in clearance of apoptotic cells and in protective immune responses, but also pose a risk of progression to leukemia/lymphoma. Differential Lin28b expression in fetal and adult human B-cell precursors showed that human B-cell development may resemble mouse, with self-reactive "innate-like" B cells generated early in life. It remains to be determined whether such human B cells have a higher propensity to leukemic progression. This review describes our recent research with CD5(+) B cells and presents our perspective on their role in disease.


Assuntos
Subpopulações de Linfócitos B/imunologia , Linfócitos B/imunologia , Antígenos CD5/imunologia , Linfopoese/imunologia , Células Precursoras de Linfócitos B/imunologia , Animais , Feto , Humanos , Leucemia de Células B/imunologia
8.
Blood ; 122(16): 2848-55, 2013 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-23926303

RESUMO

Interferon regulatory factor 4 (IRF4) is a critical transcriptional regulator of B-cell development and function. A recent genome-wide single-nucleotide polymorphism (SNP) association study identified IRF4 as a major susceptibility gene in chronic lymphocytic leukemia (CLL). Although the SNPs located in the IRF4 gene were linked to a downregulation of IRF4 in CLL patients, whether a low level of IRF4 is critical for CLL development remains unclear. In rodents, CLL cells are derived from B1 cells whose population is dramatically expanded in immunoglobulin heavy chain Vh11 knock-in mice. We bred a Vh11 knock-in allele into IRF4-deficient mice (IRF4(-/-)Vh11). Here, we report that IRF4(-/-)Vh11 mice develop spontaneous early-onset CLL with 100% penetrance. Further analysis shows that IRF4(-/-)Vh11 CLL cells proliferate predominantly in spleen and express high levels of Mcl-1. IRF4(-/-)Vh11 CLL cells are resistant to apoptosis but reconstitution of IRF4 expression in the IRF4(-/-)Vh11 CLL cells inhibits their survival. Thus, our study demonstrates for the first time a causal relationship between low levels of IRF4 and the development of CLL. Moreover, our findings establish IRF4(-/-)Vh11 mice as a novel mouse model of CLL that not only is valuable for dissecting molecular pathogenesis of CLL but could also be used for therapeutic purposes.


Assuntos
Regulação Leucêmica da Expressão Gênica , Fatores Reguladores de Interferon/metabolismo , Leucemia Linfocítica Crônica de Células B/metabolismo , Alelos , Animais , Apoptose , Transplante de Células , Cruzamentos Genéticos , Citometria de Fluxo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Fenótipo , Baço/metabolismo
9.
Clin Exp Rheumatol ; 33(4 Suppl 92): S80-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26457505

RESUMO

Natural antibodies produced by CD5+ B1 B cells include anti-thymocyte autoantibody (ATA). Transgenic mice bearing the Ig-µ heavy chain of a prototypic ATA, V(H)3609Vκ21c, demonstrated a critical requirement for self-antigen in the accumulation of ATA B cells and production of high levels of serum ATA. Further work with ATA-µκ transgenic mice revealed that, while development of most B cells were blocked at an immature stage in spleen, some mature ATA B cells were present. ATA-µκ transgenic mice with varying levels of Thy-1 autoantigen showed a clear relationship between BCR crosslinking and B cell fate, with low levels generating marginal zone ATA B cells and complete antigen absence allowing maturation to follicular ATA B cells. Finally, different fates of developing ATA B cells encountering high levels self-antigen may be accounted for by variations in the response of newly formed B cells arising from foetal and adult development.


Assuntos
Autoanticorpos/imunologia , Autoimunidade , Subpopulações de Linfócitos B/imunologia , Seleção Clonal Mediada por Antígeno , Isoanticorpos/imunologia , Animais , Autoanticorpos/metabolismo , Subpopulações de Linfócitos B/metabolismo , Antígenos CD5/imunologia , Genótipo , Humanos , Imunoglobulina M/imunologia , Imunoglobulina M/metabolismo , Isoanticorpos/genética , Isoanticorpos/metabolismo , Camundongos Transgênicos , Fenótipo , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais , Antígenos Thy-1/imunologia , Antígenos Thy-1/metabolismo
10.
Blood ; 119(23): 5438-48, 2012 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-22517907

RESUMO

The role of hedgehog (Hh) signaling in B lymphopoiesis has remained unclear. We observed that the proliferation of pro-B cells in stromal cocultures was impaired by interruption of Hh signaling, prompting us to investigate whether the target of Hh antagonism was intrinsic or extrinsic to the B-lymphoid compartment. In the present study, using conditional deletion of the pathway activator gene Smo, we found that cell-autonomous Hh signaling is dispensable for B-cell development, B-lymphoid repopulation of the BM, and humoral immune function. In contrast, depletion of the Smo protein from stromal cells was associated with impaired generation of B-lymphoid cells from hematopoietic stem progenitor cells, whereas reciprocal removal of Smo from these cells had no effect on the production of B-cell progenitors. Depletion of Smo from stromal cells was associated with coordinate down-regulation of genes for which expression is associated with osteoblastoid identity and B-lymphopoietic activity. The results of the present study suggest that activity of the Hh pathway within stromal cells promotes B lymphopoiesis in a non-cell-autonomous fashion.


Assuntos
Linfócitos B/citologia , Proteínas Hedgehog/metabolismo , Células-Tronco Hematopoéticas/citologia , Linfopoese , Receptores Acoplados a Proteínas G/metabolismo , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Deleção de Genes , Proteínas Hedgehog/antagonistas & inibidores , Células-Tronco Hematopoéticas/metabolismo , Imunidade Humoral , Camundongos , Camundongos Endogâmicos C57BL , Células Precursoras de Linfócitos B/citologia , Células Precursoras de Linfócitos B/metabolismo , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais , Receptor Smoothened , Células Estromais/citologia , Células Estromais/metabolismo
11.
J Immunol ; 186(5): 3047-57, 2011 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-21307297

RESUMO

T and B lymphocytes are developmentally and functionally related cells of the immune system, representing the two major branches of adaptive immunity. Although originating from a common precursor, they play very different roles: T cells contribute to and drive cell-mediated immunity, whereas B cells secrete Abs. Because of their functional importance and well-characterized differentiation pathways, T and B lymphocytes are ideal cell types with which to understand how functional differences are encoded at the transcriptional level. Although there has been a great deal of interest in defining regulatory factors that distinguish T and B cells, a truly genomewide view of the transcriptional differences between these two cells types has not yet been taken. To obtain a more global perspective of the transcriptional differences underlying T and B cells, we exploited the statistical power of combinatorial profiling on different microarray platforms, and the breadth of the Immunological Genome Project gene expression database, to generate robust differential signatures. We find that differential expression in T and B cells is pervasive, with the majority of transcripts showing statistically significant differences. These distinguishing characteristics are acquired gradually, through all stages of B and T differentiation. In contrast, very few T versus B signature genes are uniquely expressed in these lineages, but are shared throughout immune cells.


Assuntos
Subpopulações de Linfócitos B/imunologia , Perfilação da Expressão Gênica/métodos , Genoma , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Subpopulações de Linfócitos T/imunologia , Transcrição Gênica/imunologia , Animais , Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Linhagem da Célula/genética , Linhagem da Célula/imunologia , Sequência Consenso/genética , Sequência Consenso/imunologia , Perfilação da Expressão Gênica/estatística & dados numéricos , Ensaios de Triagem em Larga Escala/métodos , Ensaios de Triagem em Larga Escala/estatística & dados numéricos , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos/estatística & dados numéricos , Distribuição Aleatória , Transdução de Sinais/imunologia , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/metabolismo
12.
J Exp Med ; 203(3): 675-87, 2006 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-16505143

RESUMO

We describe here three CD19- B cell precursor populations in mouse bone marrow identified using 12-color flow cytometry. Cell transfer experiments indicate lineage potentials consistent with multilineage progenitor (MLP), common lymphoid progenitor (CLP), and B lineage-restricted pre-pro-B (Fr. A), respectively. However, single cell in vitro assays reveal lineage plasticity: lymphoid/myeloid lineage potential for CLP and B/T lineage potential for Fr. A. Despite myeloid potential, recombination activating gene 2 reporter activation is first detected at low levels in most MLP cells, with 95% of CLPs showing 10-fold increased levels. Furthermore, single cell analysis shows that half of CLP and 90% of Fr. A cells contain heavy chain DJ rearrangements. These data, together with expression profiles of lineage-specific genes, demonstrate progressive acquisition of B lineage potential and support an asynchronous view of early B cell development, in which B lineage specification initiates in the MLP/CLP stage, whereas myeloid potential is not lost until the pre-pro-B (Fr. A) stage, and B/T lymphoid plasticity persists until the CD19+ pro-B stage. Thus, MLP, CLP, and Fr. A represent progressively B lineage-specified stages in development, before the CD19+ B lineage-committed pro-B stage.


Assuntos
Antígenos CD19/imunologia , Linfócitos B/imunologia , Diferenciação Celular/imunologia , Rearranjo Gênico do Linfócito B/imunologia , Células-Tronco Hematopoéticas/imunologia , Linfopoese/imunologia , Animais , Antígenos CD19/genética , Linfócitos B/citologia , Diferenciação Celular/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/imunologia , Feminino , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Rearranjo Gênico do Linfócito B/genética , Células-Tronco Hematopoéticas/citologia , Cadeias Pesadas de Imunoglobulinas , Linfopoese/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos ICR
13.
Adv Exp Med Biol ; 750: 227-38, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22903678

RESUMO

Naturally occurring antibodies (NAbs) produced by CD5(+) B-1 B cells include those with specificity for thymocytes (anti-thymocyte autoantibody, ATA). Here we describe a prototypic example, encoded by an unmutated immunoglobulin µ/κ heavy chain/light chain. Studies with ATA-µ ("heavy chain only") transgenic mice demonstrated a critical requirement for self-antigen in the accumulation of B cells with this specificity and for the production of high levels of serum ATA NAb. Furthermore, analysis of B-cell development in ATA-µκ ("heavy and light chain") transgenic mice revealed two distinct responses by B cells to expression of this B-cell receptor (BCR). (1) Most B cells developing from bone marrow of adult mice were blocked at an immature stage in spleen and only escaped apoptosis by editing their BCR to eliminate the ATA specificity. (2) Some B cells differentiated to antibody-forming cells without altering their specificity, produced high levels of serum ATA, and many ATA-secreting plasma cells were observed in spleen. Finally, examination of B-cell development and ATA NAb production in ATA-µκ transgenic mice with levels of Thy-1 autoantigen varying from very low to above physiologic reveals a clear relationship between BCR crosslinking by antigen and B-cell fate. Low levels of Thy-1 autoantigen resulted in diversion of ATA B cells into the marginal zone B-cell compartment, presumably because of reduced BCR signaling. Thus, our studies demonstrate a key positive selection step in the development of NAb-producing B cells and show that most of these cells in adult mice bearing such specificities fail to reach a mature stage. Importantly, because these specificities are isolated from B-1 B cells and, when expressed as transgenes, guide development into the B-1 or marginal zone B-cell pool, we identify these B cells as a major source of natural autoantibodies in mice.


Assuntos
Especificidade de Anticorpos/imunologia , Autoanticorpos/imunologia , Linfócitos B/imunologia , Cadeias kappa de Imunoglobulina/imunologia , Cadeias mu de Imunoglobulina/imunologia , Receptores de Antígenos de Linfócitos B/imunologia , Animais , Soro Antilinfocitário/imunologia , Autoantígenos/imunologia , Linfócitos B/citologia , Diferenciação Celular/imunologia , Camundongos , Camundongos Transgênicos , Baço/citologia , Baço/imunologia , Timócitos/citologia , Timócitos/imunologia
14.
Proc Natl Acad Sci U S A ; 106(2): 522-7, 2009 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-19116268

RESUMO

Allelic exclusion of Ig gene expression is necessary to limit the number of functional receptors to one per B cell. The mechanism underlying allelic exclusion is unknown. Because germline transcription of Ig and TCR loci is tightly correlated with rearrangement, we created two novel knock-in mice that report transcriptional activity of the Jkappa germline promoters in the Igkappa locus. Analysis of these mice revealed that germline transcription is biallelic and occurs in all pre-B cells. Moreover, we found that the two germline promoters in this region are not equivalent but that the distal promoter accounts for the vast majority of observed germline transcript in pre-B cells while the activity of the proximal promoter increases later in development. Allelic exclusion of the Igkappa locus thus occurs at the level of rearrangement, but not germline transcription.


Assuntos
Alelos , Linfócitos B/citologia , Cadeias kappa de Imunoglobulina/genética , Regiões Promotoras Genéticas , Transcrição Gênica , Animais , Linfócitos B/imunologia , Técnicas de Introdução de Genes , Rearranjo Gênico , Humanos , Camundongos , Camundongos Transgênicos , Células Precursoras de Linfócitos B/citologia , Células Precursoras de Linfócitos B/imunologia
15.
J Immunol ; 182(1): 207-15, 2009 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-19109151

RESUMO

Fas/Apo-1 signals through the FADD (Fas-associated death domain) adaptor protein, which recruits and activates the apical caspase 8 and leads to apoptosis. Cellular FLIP (cFLIP) is a homolog of caspase 8 and is also capable of binding to FADD. Previous studies suggest that cFLIP could either enhance or inhibit apoptosis and lead to NF-kappaB and Erk1/2 activation. Like FADD or caspase 8 deficiency, a lack of cFLIP disrupts embryogenesis and T cell proliferation. It has been demonstrated that B cells lacking either FADD or caspase 8 were defective in both Fas-induced apoptosis and TLR-induced proliferation, which indicates that these death-inducing proteins have an additional role in regulating innate immunity. To analyze the function of cFLIP in B cells, conditional deletion of cFLIP was induced by using CD19(Cre). The resulting B cell-specific cFLIP-deficient mice were found to have reduced numbers of peripheral B cells that were hypersensitive to Fas-induced apoptosis and impaired in proliferation induced by TLRs and the BCR. Furthermore, there was aberrant expression of costimulatory proteins and activation markers in cFLIP-deficient B cells. Whereas LPS-induced activation of NF-kappaB and Erk1/2 appears to be unaffected, p38 and Jnk were spontaneously activated and hyperinduced in cFLIP-deficient B cells. Therefore, these data revealed novel functions of cFLIP in B cells.


Assuntos
Linfócitos B/citologia , Linfócitos B/enzimologia , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/fisiologia , Proliferação de Células , Proteína Quinase 9 Ativada por Mitógeno/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Apoptose/imunologia , Linfócitos B/imunologia , Células da Medula Óssea/citologia , Células da Medula Óssea/enzimologia , Células da Medula Óssea/imunologia , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/deficiência , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/genética , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/enzimologia , Células-Tronco Hematopoéticas/imunologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos
16.
J Exp Med ; 197(1): 87-99, 2003 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-12515816

RESUMO

A natural serum autoantibody specific for the Thy-1 glycoprotein (anti-Thy-1 autoantibody [ATA]) is produced by B-1 cells that are positively selected by self-antigen. Here, using ATA micro kappa transgenic mice we show that cells with this B cell receptor are negatively selected during bone marrow (BM) development. In a Thy-1 null environment, BM ATA B cells progress to a normal follicular stage in spleen. However, in a self-antigen-positive environment, development is arrested at an immature stage in the spleen, concomitant with induction of CD5. Such cells are tolerant and short-lived, different from B-1. Nonetheless, ATA-positive selection was evident by self-antigen-dependent high serum ATA production, comprising approximately 90% of serum immunoglobulin M in ATA micro kappa mice. Splenectomy did not eliminate ATA production and transfer of tolerant splenic B cells did not induce it. These findings demonstrate that B-1 positive selection, resulting in the production of natural serum ATA, arises independently from the major pathway of BM B cell development and selection.


Assuntos
Autoanticorpos/biossíntese , Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/imunologia , Células da Medula Óssea/citologia , Células da Medula Óssea/imunologia , Diferenciação Celular , Antígenos Thy-1/imunologia , Animais , Autoanticorpos/imunologia , Autoantígenos/imunologia , Subpopulações de Linfócitos B/metabolismo , Células da Medula Óssea/metabolismo , Antígenos CD5/análise , Antígenos CD5/imunologia , Antígenos CD5/metabolismo , Movimento Celular , Citometria de Fluxo , Tolerância Imunológica , Imunoglobulina M/análise , Imunoglobulina M/imunologia , Imunofenotipagem , Camundongos , Baço/citologia , Baço/imunologia , Esplenectomia , Antígenos Thy-1/análise
17.
Curr Opin Immunol ; 18(5): 547-55, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16879952

RESUMO

B-1 (CD5+) B cells constitute a phenotypic and functionally distinct population of B cells in mouse that show enriched expression of autoreactive B-cell antigen receptors and that produce several types of natural autoantibodies. Recently, there has been much progress in this field of research. Evidence has appeared for the existence of distinctive B-cell precursors that preferentially generate B-1 B cells, and the crucial requirement for strong B-cell antigen receptor signaling in the maturation of B-1 B cells has been established. Other work focuses on a phenotypically similar population that lacks CD5, termed 'B-1b', which shows similarities and differences from most CD5+ B cells in both development and function. The relationship of normal B-1 cells with B-cell lymphomas and leukemias continues to be a subject of interest and debate.


Assuntos
Subpopulações de Linfócitos B/fisiologia , Leucemia/imunologia , Animais , Autoanticorpos/sangue , Autoantígenos/imunologia , Subpopulações de Linfócitos B/imunologia , Antígenos CD5 , Imunofenotipagem , Leucemia/sangue , Linfopoese , Camundongos , Receptores de Antígenos de Linfócitos B/imunologia , Transdução de Sinais
19.
Front Immunol ; 10: 457, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30930899

RESUMO

The Lin28b+Let7- axis in fetal/neonatal development plays a role in promoting CD5+ B1a cell generation as a B-1 B cell developmental outcome. Here we identify the Let7 target, Arid3a, as a crucial molecular effector of the B-1 cell developmental program. Arid3a expression is increased at pro-B cell stage and markedly increased at pre-B and immature B cell stages in the fetal/neonatal liver B-1 development relative to that in the Lin28b-Let7+ adult bone marrow (BM) B-2 cell development. Analysis of B-lineage restricted Lin28b transgenic (Tg) mice, Arid3a knockout and Arid3a Tg mice, confirmed that increased Arid3a allows B cell generation without requiring surrogate light chain (SLC) associated pre-BCR stage, and prevents MHC class II cell expression at the pre-B and newly generated immature B cell stages, distinct from pre-BCR dependent B development with MHC class II in adult BM. Moreover, Arid3a plays a crucial role in supporting B1a cell generation. The increased Arid3a leads higher Myc and Bhlhe41, and lower Siglec-G and CD72 at the pre-B and immature B cell stages than normal adult BM, to allow BCR signaling induced B1a cell generation. Arid3a-deficiency selectively blocks the development of B1a cells, while having no detectable effect on CD5- B1b, MZ B, and FO B cell generation resembling B-2 development outcome. Conversely, enforced expression of Arid3a by transgene is sufficient to promote the development of B1a cells from adult BM. Under the environment change between birth to adult, altered BCR repertoire in increased B1a cells occurred generated from adult BM. However, crossed with B1a-restricted VH/D/J IgH knock-in mice allowed to confirm that SLC-unassociated B1a cell increase and CLL/lymphoma generation can occur in aged from Arid3a increased adult BM. These results confirmed that in fetal/neonatal normal mice, increased Arid3a at the pre-B cell and immature B cell stages is crucial for generating B1a cells together with the environment for self-ligand reactive BCR selection, B1a cell maintenance, and potential for development of CLL/Lymphoma in aged mice.


Assuntos
Subpopulações de Linfócitos B/imunologia , Proteínas de Ligação a DNA/imunologia , Células Precursoras de Linfócitos B/metabolismo , Fatores de Transcrição/imunologia , Envelhecimento/genética , Envelhecimento/imunologia , Animais , Proteínas de Ligação a DNA/genética , Regulação Leucêmica da Expressão Gênica , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/imunologia , Camundongos , Camundongos Knockout , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/imunologia , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Fatores de Transcrição/genética
20.
PLoS Biol ; 3(3): e82, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15752064

RESUMO

In developing B lymphocytes, a successful V(D)J heavy chain (HC) immunoglobulin (Ig) rearrangement establishes HC allelic exclusion and signals pro-B cells to advance in development to the pre-B stage. A subsequent functional light chain (LC) rearrangement then results in the surface expression of IgM at the immature B cell stage. Here we show that interruption of basal IgM signaling in immature B cells, either by the inducible deletion of surface Ig via Cre-mediated excision or by incubating cells with the tyrosine kinase inhibitor herbimycin A or the phosphatidylinositol 3-kinase inhibitor wortmannin, led to a striking "back-differentiation" of cells to an earlier stage in B cell development, characterized by the expression of pro-B cell genes. Cells undergoing this reversal in development also showed evidence of new LC gene rearrangements, suggesting an important role for basal Ig signaling in the maintenance of LC allelic exclusion. These studies identify a previously unappreciated level of plasticity in the B cell developmental program, and have important implications for our understanding of central tolerance mechanisms.


Assuntos
Linfócitos B/imunologia , Imunoglobulinas/fisiologia , Transdução de Sinais/imunologia , Androstadienos/farmacologia , Animais , Linfócitos B/efeitos dos fármacos , Células da Medula Óssea/citologia , Células da Medula Óssea/imunologia , Células Cultivadas , Rearranjo Gênico , Rearranjo Gênico do Linfócito B , Proteínas de Fluorescência Verde/genética , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Leves de Imunoglobulina/genética , Imunoglobulina M/imunologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Wortmanina
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