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Germinal center dark zone

Jing Wang, Sichen Liu, Baidong Hou, Meixiang Yang, Zhongjun Dong, Hai Qi, Wanli Liu
Class-switch recombination (CSR) and somatic hypermutation (SHM) occur during the differentiation of germinal center B cells (GCBs). Activation-induced cytidine deaminase (AID) is responsible for both CSR and SHM in GCBs. Here, we show that ablation of PTEN through the Cγ1-Cre mediated recombination significantly influences the CSR and SHM responses. The GCs fail to produce the IgG1 B cells, the high affinity antibodies and nearly lost the dark zone (DZ) in Ptenfl/fl Cγ1Cre/+ mice after immunization, suggesting the impaired GC structure...
2018: Frontiers in Immunology
Elisa Monzón-Casanova, Michael Screen, Manuel D Díaz-Muñoz, Richard M R Coulson, Sarah E Bell, Greta Lamers, Michele Solimena, Christopher W J Smith, Martin Turner
Antibody affinity maturation occurs in germinal centers (GCs), where B cells cycle between the light zone (LZ) and the dark zone. In the LZ, GC B cells bearing immunoglobulins with the highest affinity for antigen receive positive selection signals from helper T cells, which promotes their rapid proliferation. Here we found that the RNA-binding protein PTBP1 was needed for the progression of GC B cells through late S phase of the cell cycle and for affinity maturation. PTBP1 was required for proper expression of the c-MYC-dependent gene program induced in GC B cells receiving T cell help and directly regulated the alternative splicing and abundance of transcripts that are increased during positive selection to promote proliferation...
March 2018: Nature Immunology
Brian J Laidlaw, Yisi Lu, Robert A Amezquita, Jason S Weinstein, Jason A Vander Heiden, Namita T Gupta, Steven H Kleinstein, Susan M Kaech, Joe Craft
CD4+ follicular regulatory T (Tfr ) cells suppress B cell responses through modulation of follicular helper T (Tfh ) cells and germinal center (GC) development. We found that Tfr cells can also promote the GC response through provision of interleukin-10 (IL-10) after acute infection with lymphocytic choriomeningitis virus (LCMV). Sensing of IL-10 by B cells was necessary for optimal development of the GC response. GC B cells formed in the absence of Treg cell-derived IL-10 displayed an altered dark zone state and decreased expression of the transcription factor Forkhead box protein 1 (FOXO1)...
October 20, 2017: Science Immunology
Christian T Mayer, Anna Gazumyan, Ervin E Kara, Alexander D Gitlin, Jovana Golijanin, Charlotte Viant, Joy Pai, Thiago Y Oliveira, Qiao Wang, Amelia Escolano, Max Medina-Ramirez, Rogier W Sanders, Michel C Nussenzweig
B cells undergo rapid cell division and affinity maturation in anatomically distinct sites in lymphoid organs called germinal centers (GCs). Homeostasis is maintained in part by B cell apoptosis. However, the precise contribution of apoptosis to GC biology and selection is not well defined. We developed apoptosis-indicator mice and used them to visualize, purify, and characterize dying GC B cells. Apoptosis is prevalent in the GC, with up to half of all GC B cells dying every 6 hours. Moreover, programmed cell death is differentially regulated in the light zone and the dark zone: Light-zone B cells die by default if they are not positively selected, whereas dark-zone cells die when their antigen receptors are damaged by activation-induced cytidine deaminase...
October 13, 2017: Science
Jonatan Ersching, Alejo Efeyan, Luka Mesin, Johanne T Jacobsen, Giulia Pasqual, Brian C Grabiner, David Dominguez-Sola, David M Sabatini, Gabriel D Victora
During antibody affinity maturation, germinal center (GC) B cells cycle between affinity-driven selection in the light zone (LZ) and proliferation and somatic hypermutation in the dark zone (DZ). Although selection of GC B cells is triggered by antigen-dependent signals delivered in the LZ, DZ proliferation occurs in the absence of such signals. We show that positive selection triggered by T cell help activates the mechanistic target of rapamycin complex 1 (mTORC1), which promotes the anabolic program that supports DZ proliferation...
June 20, 2017: Immunity
Nike J Kräutler, Dan Suan, Danyal Butt, Katherine Bourne, Jana R Hermes, Tyani D Chan, Christopher Sundling, Warren Kaplan, Peter Schofield, Jennifer Jackson, Antony Basten, Daniel Christ, Robert Brink
Plasma cells (PCs) derived from germinal centers (GCs) secrete the high-affinity antibodies required for long-term serological immunity. Nevertheless, the process whereby GC B cells differentiate into PCs is uncharacterized, and the mechanism underlying the selective PC differentiation of only high-affinity GC B cells remains unknown. In this study, we show that differentiation into PCs is induced among a discrete subset of high-affinity B cells residing within the light zone of the GC. Initiation of differentiation required signals delivered upon engagement with intact antigen...
May 1, 2017: Journal of Experimental Medicine
Takeshi Inoue, Ryo Shinnakasu, Wataru Ise, Chie Kawai, Takeshi Egawa, Tomohiro Kurosaki
Germinal center (GC) B cells cycle between two states, the light zone (LZ) and the dark zone (DZ), and in the latter they proliferate and hypermutate their immunoglobulin genes. How this functional transition takes place is still controversial. In this study, we demonstrate that ablation of Foxo1 after GC development led to the loss of the DZ GC B cells and disruption of the GC architecture, which is consistent with recent studies. Mechanistically, even upon provision of adequate T cell help, Foxo1-deficient GC B cells showed less proliferative expansion than controls...
April 3, 2017: Journal of Experimental Medicine
Chun Chou, Daniel J Verbaro, Elena Tonc, Melanie Holmgren, Marina Cella, Marco Colonna, Deepta Bhattacharya, Takeshi Egawa
B cells diversify and affinity mature their antigen receptor repertoire in germinal centers (GCs). GC B cells receive help signals during transient interaction with T cells, yet it remains unknown how these transient T-B interactions in the light zone sustain the subsequent proliferative program of selected B cells that occurs in the anatomically distant dark zone. Here, we show that the transcription factor AP4 was required for sustained GC B cell proliferation and subsequent establishment of a diverse and protective antibody repertoire...
September 20, 2016: Immunity
Elisa Ferretti, Maurilio Ponzoni, Claudio Doglioni, Vito Pistoia
The germinal center (GC) is a dynamic structure formed by proliferating B cells in the follicles of secondary lymphoid organs during T cell-dependent antibody responses to exogenous antigens. GC is composed by a dark zone, enriched in proliferating centroblasts (CBs), and a light zone where CBs migrate and transform into centrocytes (CCs), a minority of which is selected to survive, undergoes Ig class-switch recombination, and differentiates into memory B cells or long-lived plasma cells. CBs express CXCR4 and are attracted to the dark zone by stromal cell-derived CXCL12, whereas CCs express CXCR5 and are recruited to the light zone along a gradient of CXCL13 produced by follicular dendritic cells (FDCs)...
November 2016: Journal of Leukocyte Biology
Sally E Trabucco, Rachel M Gerstein, Hong Zhang
The germinal center (GC) reaction produces high-affinity Abs for a robust adaptive immune response. When dysregulated, the same processes cause GC B cells to become susceptible to lymphomagenesis. It is important to understand how the GC reaction is regulated. In this study, we show that transcription factor YY1 is required to maintain a robust GC reaction in mice. Selective ablation of YY1 significantly decreased in the frequency and number of GC B cells during the GC reaction. This decrease of GC B cells was accompanied by increased apoptosis in these cells...
September 1, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Christof Schneider, Ning Kon, Letizia Amadori, Qiong Shen, Friederike H Schwartz, Benjamin Tischler, Marion Bossennec, David Dominguez-Sola, Govind Bhagat, Wei Gu, Katia Basso, Riccardo Dalla-Favera
The BCL6 proto-oncogene encodes a transcriptional repressor that is required for the germinal center (GC) reaction and is implicated in lymphomagenesis. BCL6 protein stability is regulated by F-box protein 11 (FBXO11)-mediated ubiquitination and degradation, which is impaired in ∼6% of diffuse large B-cell lymphomas that carry inactivating genetic alterations targeting the FBXO11 gene. In order to investigate the role of FBXO11 in vivo, we analyzed GC-specific FBXO11 knockout mice. FBXO11 reduction or loss led to an increased number of GC B cells, to an altered ratio of GC dark zone to light zone cells, and to higher levels of BCL6 protein in GC B cells...
August 4, 2016: Blood
Jane A Healy, Adrienne Nugent, Rachel E Rempel, Andrea B Moffitt, Nicholas S Davis, Xiaoyu Jiang, Jennifer R Shingleton, Jenny Zhang, Cassandra Love, Jyotishka Datta, Matthew E McKinney, Tiffany J Tzeng, Nina Wettschureck, Stefan Offermanns, Katelyn A Walzer, Jen-Tsan Chi, Suhail A K Rasheed, Patrick J Casey, Izidore S Lossos, Sandeep S Dave
GNA13 is the most frequently mutated gene in germinal center (GC)-derived B-cell lymphomas, including nearly a quarter of Burkitt lymphoma and GC-derived diffuse large B-cell lymphoma. These mutations occur in a pattern consistent with loss of function. We have modeled the GNA13-deficient state exclusively in GC B cells by crossing the Gna13 conditional knockout mouse strain with the GC-specific AID-Cre transgenic strain. AID-Cre(+) GNA13-deficient mice demonstrate disordered GC architecture and dark zone/light zone distribution in vivo, and demonstrate altered migration behavior, decreased levels of filamentous actin, and attenuated RhoA activity in vitro...
June 2, 2016: Blood
Lena Krzyzak, Christine Seitz, Anne Urbat, Stefan Hutzler, Christian Ostalecki, Joachim Gläsner, Andreas Hiergeist, André Gessner, Thomas H Winkler, Alexander Steinkasserer, Lars Nitschke
CD83 is a maturation marker for dendritic cells. In the B cell lineage, CD83 is expressed especially on activated B cells and on light zone B cells during the germinal center (GC) reaction. The function of CD83 during GC responses is unclear. CD83(-/-) mice have a strong reduction of CD4(+) T cells, which makes it difficult to analyze a functional role of CD83 on B cells during GC responses. Therefore, in the present study we generated a B cell-specific CD83 conditional knockout (CD83 B-cKO) model. CD83 B-cKO B cells show defective upregulation of MHC class II and CD86 expression and impaired proliferation after different stimuli...
May 1, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Alba Llibre, Constantino López-Macías, Teresa Marafioti, Hema Mehta, Amy Partridge, Carina Kanzig, Felice Rivellese, Jacob D Galson, Lucy J Walker, Paul Milne, Rodney E Phillips, Dominic F Kelly, Gordon J Freeman, Mohey Eldin El Shikh, Paul Klenerman, Christian B Willberg
Germinal centers (GCs) are microanatomical structures critical for the development of high-affinity Abs and B cell memory. They are organized into two zones, light and dark, with coordinated roles, controlled by local signaling. The innate lectin-like transcript 1 (LLT1) is known to be expressed on B cells, but its functional role in the GC reaction has not been explored. In this study, we report high expression of LLT1 on GC-associated B cells, early plasmablasts, and GC-derived lymphomas. LLT1 expression was readily induced via BCR, CD40, and CpG stimulation on B cells...
March 1, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Jason G Cyster
Germinal center B cells exist in two conditions, a dark zone state and a light zone state. Two studies in this issue (Dominguez-Sola et al., 2015; Sander et al., 2015) report that Foxo1 deficiency causes an almost complete loss of dark zone cells and an inability to undergo robust antibody affinity maturation.
December 15, 2015: Immunity
Sandrine Sander, Van Trung Chu, Tomoharu Yasuda, Andrew Franklin, Robin Graf, Dinis Pedro Calado, Shuang Li, Koshi Imami, Matthias Selbach, Michela Di Virgilio, Lars Bullinger, Klaus Rajewsky
Phosphatidylinositol 3' OH kinase (PI3K) signaling and FOXO transcription factors play opposing roles at several B cell developmental stages. We show here abundant nuclear FOXO1 expression in the proliferative compartment of the germinal center (GC), its dark zone (DZ), and PI3K activity, downregulating FOXO1, in the light zone (LZ), where cells are selected for further differentiation. In the LZ, however, FOXO1 was expressed in a fraction of cells destined for DZ reentry. Upon FOXO1 ablation or induction of PI3K activity, GCs lost their DZ, owing at least partly to downregulation of the chemokine receptor CXCR4...
December 15, 2015: Immunity
David Dominguez-Sola, Jennifer Kung, Antony B Holmes, Victoria A Wells, Tongwei Mo, Katia Basso, Riccardo Dalla-Favera
The pathways regulating formation of the germinal center (GC) dark zone (DZ) and light zone (LZ) are unknown. In this study we show that FOXO1 transcription factor expression was restricted to the GC DZ and was required for DZ formation, since its absence in mice led to the loss of DZ gene programs and the formation of LZ-only GCs. FOXO1-negative GC B cells displayed normal somatic hypermutation but defective affinity maturation and class switch recombination. The function of FOXO1 in sustaining the DZ program involved the trans-activation of the chemokine receptor CXCR4, and cooperation with the BCL6 transcription factor in the trans-repression of genes involved in immune activation, DNA repair, and plasma cell differentiation...
December 15, 2015: Immunity
Lauren B Rodda, Oliver Bannard, Burkhard Ludewig, Takashi Nagasawa, Jason G Cyster
The germinal center (GC) is divided into a dark zone (DZ) and a light zone (LZ). GC B cells must cycle between these zones to achieve efficient Ab affinity maturation. Follicular dendritic cells (FDCs) are well characterized for their role in supporting B cell Ag encounter in primary follicles and in the GC LZ. However, the properties of stromal cells supporting B cells in the DZ are relatively unexplored. Recent work identified a novel stromal population of Cxcl12-expressing reticular cells (CRCs) in murine GC DZs...
November 15, 2015: Journal of Immunology: Official Journal of the American Association of Immunologists
Helene Kretzmer, Stephan H Bernhart, Wei Wang, Andrea Haake, Marc A Weniger, Anke K Bergmann, Matthew J Betts, Enrique Carrillo-de-Santa-Pau, Gero Doose, Jana Gutwein, Julia Richter, Volker Hovestadt, Bingding Huang, Daniel Rico, Frank Jühling, Julia Kolarova, Qianhao Lu, Christian Otto, Rabea Wagener, Judith Arnolds, Birgit Burkhardt, Alexander Claviez, Hans G Drexler, Sonja Eberth, Roland Eils, Paul Flicek, Siegfried Haas, Michael Humme, Dennis Karsch, Hinrik H D Kerstens, Wolfram Klapper, Markus Kreuz, Chris Lawerenz, Dido Lenzek, Markus Loeffler, Cristina López, Roderick A F MacLeod, Joost H A Martens, Marta Kulis, José Ignacio Martín-Subero, Peter Möller, Inga Nage, Simone Picelli, Inga Vater, Marius Rohde, Philip Rosenstiel, Maciej Rosolowski, Robert B Russell, Markus Schilhabel, Matthias Schlesner, Peter F Stadler, Monika Szczepanowski, Lorenz Trümper, Hendrik G Stunnenberg, Ralf Küppers, Ole Ammerpohl, Peter Lichter, Reiner Siebert, Steve Hoffmann, Bernhard Radlwimmer
Although Burkitt lymphomas and follicular lymphomas both have features of germinal center B cells, they are biologically and clinically quite distinct. Here we performed whole-genome bisulfite, genome and transcriptome sequencing in 13 IG-MYC translocation-positive Burkitt lymphoma, nine BCL2 translocation-positive follicular lymphoma and four normal germinal center B cell samples. Comparison of Burkitt and follicular lymphoma samples showed differential methylation of intragenic regions that strongly correlated with expression of associated genes, for example, genes active in germinal center dark-zone and light-zone B cells...
November 2015: Nature Genetics
Lydia Hopp, Henry Löffler-Wirth, Hans Binder
Mature B-cell lymphoma is a clinically and biologically highly diverse disease. Its diagnosis and prognosis is a challenge due to its molecular heterogeneity and diverse regimes of biological dysfunctions, which are partly driven by epigenetic mechanisms. We here present an integrative analysis of DNA methylation and gene expression data of several lymphoma subtypes. Our study confirms previous results about the role of stemness genes during development and maturation of B-cells and their dysfunction in lymphoma locking in more proliferative or immune-reactive states referring to B-cell functionalities in the dark and light zone of the germinal center and also in plasma cells...
2015: Genes
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