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Isotype class switching

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https://www.readbyqxmd.com/read/29907762/duplication-of-a-germline-promoter-downstream-of-the-igh-3-regulatory-region-impairs-class-switch-recombination
#1
Joana M Santos, Fatima-Zohra Braikia, Chloé Oudinet, Dania Haddad, Caroline Conte, Audrey Dauba, Ahmed Amine Khamlichi
During an adaptive immune response, B cells can change their surface immunoglobulins from IgM to IgG, IgE or IgA through a process called class switch recombination (CSR). Switching is preceded by inducible non-coding germline transcription (GLT) of the selected constant gene(s), which is largely controlled by a super-enhancer called the 3' regulatory region (3'RR). Despite intense efforts, the precise mechanisms that regulate GLT are still elusive. In order to gain additional insights into these mechanisms, we analyzed GLT and CSR in mutant B cells carrying a duplication of the promoter of the α constant gene (Iα) downstream of 3'RR...
June 15, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29875252/a-single-locus-controls-interferon-gamma-independent-antiretroviral-neutralizing-antibody-responses
#2
Melissa Kane, Felicity Deiss, Alexander Chervonsky, Tatyana V Golovkina
An essential step in the development of effective antiviral humoral responses is cytokine-triggered class switch recombination resulting in the production of antibodies of a specific isotype. Most viral and parasitic infections in mice induce predominantly IgG2a specific antibody responses that are stimulated by interferon-γ (IFN-γ). However, in some mice deficient in IFN-γ, class-switching to IgG2a antibodies is relatively unaffected, indicating that other signal(s) can be generated upon viral or parasitic infections that trigger this response...
June 6, 2018: Journal of Virology
https://www.readbyqxmd.com/read/29867973/lineage-specific-functionality-of-an-interferon-regulatory-factor-5-lupus-risk-haplotype-lack-of-b-cell-intrinsic-effects
#3
Justine Calise, Susana Marquez Renteria, Peter K Gregersen, Betty Diamond
Interferon regulatory factor 5 (IRF5) is widely recognized as a risk locus for systemic lupus erythematosus (SLE). Risk gene and IRF5 activation is triggered through toll-like receptor signaling. In myeloid cells, this leads to production of type I interferon and inflammatory cytokines, with enhanced production in cells of individuals harboring IRF5 risk alleles. Mouse models have also demonstrated the importance of IRF5 in B cell function, particularly plasma cell differentiation and isotype switching. Here, we evaluated the major SLE risk haplotype of IRF5 on the functional attributes of freshly isolated B cells from human subjects who do not have evidence of SLE or other forms of autoimmunity...
2018: Frontiers in Immunology
https://www.readbyqxmd.com/read/29768501/secretion-of-autoimmune-antibodies-in-the-human-subcutaneous-adipose-tissue
#4
Daniela Frasca, Alain Diaz, Maria Romero, Seth Thaller, Bonnie B Blomberg
The adipose tissue (AT) contributes to systemic and B cell intrinsic inflammation, reduced B cell responses and secretion of autoimmune antibodies. In this study we show that adipocytes in the human obese subcutaneous AT (SAT) secrete several pro-inflammatory cytokines and chemokines, which contribute to the establishment and maintenance of local and systemic inflammation, and consequent suboptimal immune responses in obese individuals, as we have previously shown. We also show that pro-inflammatory chemokines recruit immune cells expressing the corresponding receptors to the SAT, where they also contribute to local and systemic inflammation, secreting additional pro-inflammatory mediators...
2018: PloS One
https://www.readbyqxmd.com/read/29743314/cd8-follicular-t-cells-promote-b-cell-antibody-class-switch-in-autoimmune-disease
#5
Kristen M Valentine, Dan Davini, Travis J Lawrence, Genevieve N Mullins, Miguel Manansala, Mufadhal Al-Kuhlani, James M Pinney, Jason K Davis, Anna E Beaudin, Suzanne S Sindi, David M Gravano, Katrina K Hoyer
CD8 T cells can play both a protective and pathogenic role in inflammation and autoimmune development. Recent studies have highlighted the ability of CD8 T cells to function as T follicular helper (Tfh) cells in the germinal center in the context of infection. However, whether this phenomenon occurs in autoimmunity and contributes to autoimmune pathogenesis is largely unexplored. In this study, we show that CD8 T cells acquire a CD4 Tfh profile in the absence of functional regulatory T cells in both the IL-2-deficient and scurfy mouse models...
May 9, 2018: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/29704159/diversity-of-immunoglobulin-ig-isotypes-and-the-role-of-activation-induced-cytidine-deaminase-aid-in-fish
#6
REVIEW
Bhakti Patel, Rajanya Banerjee, Mrinal Samanta, Surajit Das
The disparate diversity in immunoglobulin (Ig) repertoire has been a subject of fascination since the emergence of prototypic adaptive immune system in vertebrates. The carboxy terminus region of activation-induced cytidine deaminase (AID) has been well established in tetrapod lineage and is crucial for its function in class switch recombination (CSR) event of Ig diversification. The absence of CSR in the paraphyletic group of fish is probably due to changes in catalytic domain of AID and lack of cis-elements in IgH locus...
June 2018: Molecular Biotechnology
https://www.readbyqxmd.com/read/29664567/memory-control-by-the-b-cell-antigen-receptor
#7
REVIEW
Niklas Engels, Jürgen Wienands
The generation of memory B cells (MBCs) that have undergone immunoglobulin class switching from IgM, which dominates primary antibody responses, to other immunoglobulin isoforms is a hallmark of immune memory. Hence, humoral immunological memory is characterized by the presence of serum immunoglobulins of IgG subtypes known as the γ-globulin fraction of blood plasma proteins. These antibodies reflect the antigen experience of B lymphocytes and their repeated triggering. In fact, efficient protection against a previously encountered pathogen is critically linked to the production of pathogen-specific IgG molecules even in those cases where the primary immune response required cellular immunity, for example, T cell-mediated clearance of intracellular pathogens such as viruses...
May 2018: Immunological Reviews
https://www.readbyqxmd.com/read/29572544/high-throughput-sequencing-reveals-similar-molecular-signatures-for-class-switch-recombination-junctions-for-the-%C3%AE-and-%C3%AE-isotypes
#8
Hussein Issaoui, Nour Ghazzaui, Alexis Saintamand, Yves Denizot, François Boyer
No abstract text is available yet for this article.
March 23, 2018: Cellular & Molecular Immunology
https://www.readbyqxmd.com/read/29535729/epigenomic-modifications-mediating-antibody-maturation
#9
REVIEW
Emily C Sheppard, Rikke Brandstrup Morrish, Michael J Dillon, Rebecca Leyland, Richard Chahwan
Epigenetic modifications, such as histone modifications, DNA methylation status, and non-coding RNAs (ncRNA), all contribute to antibody maturation during somatic hypermutation (SHM) and class-switch recombination (CSR). Histone modifications alter the chromatin landscape and, together with DNA primary and tertiary structures, they help recruit Activation-Induced Cytidine Deaminase (AID) to the immunoglobulin (Ig) locus. AID is a potent DNA mutator, which catalyzes cytosine-to-uracil deamination on single-stranded DNA to create U:G mismatches...
2018: Frontiers in Immunology
https://www.readbyqxmd.com/read/29520062/the-h2b-deubiquitinase-usp22-promotes-antibody-class-switch-recombination-by-facilitating-non-homologous-end-joining
#10
Conglei Li, Thergiory Irrazabal, Clare C So, Maribel Berru, Likun Du, Evelyn Lam, Alexanda K Ling, Jennifer L Gommerman, Qiang Pan-Hammarström, Alberto Martin
Class switch recombination (CSR) has a fundamental function during humoral immune response and involves the induction and subsequent repair of DNA breaks in the immunoglobulin (Ig) switch regions. Here we show the role of Usp22, the SAGA complex deubiquitinase that removes ubiquitin from H2B-K120, in the repair of programmed DNA breaks in vivo. Ablation of Usp22 in primary B cells results in defects in γH2AX and impairs the classical non-homologous end joining (c-NHEJ), affecting both V(D)J recombination and CSR...
March 8, 2018: Nature Communications
https://www.readbyqxmd.com/read/29503740/toll-like-receptor-1-2-agonist-pam3csk4-suppresses-lipopolysaccharide-driven-igg1-production-while-enhancing-igg2a-production-by-b-cells
#11
Sang-Hoon Lee, Seok-Rae Park
Interaction between pathogen-associated molecular patterns and pattern recognition receptors triggers innate and adaptive immune responses. Several studies have reported that toll-like receptors (TLRs) are involved in B cell proliferation, differentiation, and Ig class switch recombination (CSR). However, roles of TLRs in B cell activation and differentiation are not completely understood. In this study, we investigated the direct effect of stimulation of TLR1/2 agonist Pam3CSK4 on mouse B cell viability, proliferation, activation, Ig production, and Ig CSR in vitro ...
February 2018: Immune Network
https://www.readbyqxmd.com/read/29382466/characterization-of-sentinel-node-derived-antibodies-from-breast-cancer-patients
#12
Girja S Shukla, Stephanie C Pero, Yu-Jing Sun, Chelsea L Carman, Seth Harlow, David N Krag
Autoantibodies to breast and other cancers are commonly present in cancer patients. A method to rapidly produce these anti-cancer autoantibodies in the lab would be valuable for understanding immune events and to generate candidate reagents for therapy and diagnostics. The purpose of this report is to evaluate sentinel nodes (SNs) of breast cancer patients as a source of anti-cancer antibodies. Radiotracer lymphatic mapping in 29 patients with breast cancer confirmed the identity of the SNs which provided source cells for this study...
April 2018: Journal of Immunological Methods
https://www.readbyqxmd.com/read/28928744/ccctc-binding-factor-locks-premature-igh-germline-transcription-and-restrains-class-switch-recombination
#13
Ester Marina-Zárate, Arantxa Pérez-García, Almudena R Ramiro
In response to antigenic stimulation B cells undergo class switch recombination (CSR) at the immunoglobulin heavy chain (IgH) to replace the primary IgM/IgD isotypes by IgG, IgE, or IgA. CSR is initiated by activation-induced cytidine deaminase (AID) through the deamination of cytosine residues at the switch (S) regions of IgH. B cell stimulation promotes germline transcription (GLT) of specific S regions, a necessary event prior to CSR because it facilitates AID access to S regions. Here, we show that CCCTC-binding factor (CTCF)-deficient mice are severely impaired in the generation of germinal center B cells and plasma cells after immunization in vivo, most likely due to impaired cell survival...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28928405/nanopore-extended-field-effect-transistor-for-selective-single-molecule-biosensing
#14
Ren Ren, Yanjun Zhang, Binoy Paulose Nadappuram, Bernice Akpinar, David Klenerman, Aleksandar P Ivanov, Joshua B Edel, Yuri Korchev
There has been a significant drive to deliver nanotechnological solutions to biosensing, yet there remains an unmet need in the development of biosensors that are affordable, integrated, fast, capable of multiplexed detection, and offer high selectivity for trace analyte detection in biological fluids. Herein, some of these challenges are addressed by designing a new class of nanoscale sensors dubbed nanopore extended field-effect transistor (nexFET) that combine the advantages of nanopore single-molecule sensing, field-effect transistors, and recognition chemistry...
September 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28838616/molecular-analysis-of-immunoglobulin-variable-genes-supports-a-germinal-center-experienced-normal-counterpart-in-primary-cutaneous-diffuse-large-b-cell-lymphoma-leg-type
#15
Anne Pham-Ledard, Martina Prochazkova-Carlotti, Mélanie Deveza, Marie-Pierre Laforet, Marie Beylot-Barry, Béatrice Vergier, Marie Parrens, Jean Feuillard, Jean-Philippe Merlio, Nathalie Gachard
BACKGROUND: Immunophenotype of primary cutaneous diffuse large B-cell lymphoma, leg-type (PCLBCL-LT) suggests a germinal center-experienced B lymphocyte (BCL2+ MUM1+ BCL6+/-). OBJECTIVES: As maturation history of B-cell is "imprinted" during B-cell development on the immunoglobulin gene sequence, we studied the structure and sequence of the variable part of the genes (IGHV, IGLV, IGKV), immunoglobulin surface expression and features of class switching in order to determine the PCLBCL-LT cell of origin...
July 26, 2017: Journal of Dermatological Science
https://www.readbyqxmd.com/read/28690727/-clinical-and-immunological-profile-of-15-moroccan-patients-with-hyper-igm-syndrome
#16
Hind Ouair, Ibtihal Benhsaien, Leila Jeddane, Jalila El Bakkouri, Naima Elhafidi, Noureddine Rada, Jilali Najib, Fatima Ailal, Hanane Salih Alj, Ahmed Aziz Bousfiha
Hyper IgM syndrome is a well known genetic (primary) immunodeficiency disorder which was first described in 1961. It is caused by B lymphocyte deficiency characterized by normal or elevated serum IgM levels and low or zero levels of IgG, IgA, IgE resulting from isotype-switching deficiency. Clinical manifestations are dominated by recurrent infections, especially involving the digestive tube of the ENT sphere and the lungs. This syndrome is caused by B-cell immunoglobulin class switch deficiency and decreased capacity to induce proliferation of T lymphocytes...
2017: Pan African Medical Journal
https://www.readbyqxmd.com/read/28607112/cutting-edge-active-tgf-%C3%AE-1-released-from-garp-tgf-%C3%AE-1-complexes-on-the-surface-of-stimulated-human-b-lymphocytes-increases-class-switch-recombination-and-production-of-iga
#17
Olivier Dedobbeleer, Julie Stockis, Bas van der Woning, Pierre G Coulie, Sophie Lucas
Production of active TGF-β is regulated at a posttranslational level and implies release of the mature cytokine dimer from the inactive, latent TGF-β precursor. There are several cell-type specific mechanisms of TGF-β activation. We identified a new mechanism operating on the surface of human regulatory T cells and involving membrane protein GARP, which binds latent TGF-β1. The paracrine activity of regulatory T cell-derived TGF-β1 contributes to immunosuppression and can be inhibited with anti-GARP Abs...
July 15, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28574479/r-loops-in-the-regulation-of-antibody-gene-diversification
#18
REVIEW
Rushad Pavri
For nearly three decades, R loops have been closely linked with class switch recombination (CSR), the process that generates antibody isotypes and that occurs via a complex cascade initiated by transcription-coupled mutagenesis in switch recombination sequences. R loops form during transcription of switch recombination sequences in vitro and in vivo, and there is solid evidence that R loops are required for efficient class switching. The classical model of R loops posits that they boost mutation rates by generating stable and long tracts of single-stranded DNA that serve as the substrate for activation induced deaminase (AID), the enzyme that initiates the CSR reaction cascade by co-transcriptionally mutating ssDNA in switch recombination sequences...
June 2, 2017: Genes
https://www.readbyqxmd.com/read/28535205/a-transcriptional-serenaid-the-role-of-noncoding-rnas-in-class-switch-recombination
#19
REVIEW
William T Yewdell, Jayanta Chaudhuri
During an immune response, activated B cells may undergo class switch recombination (CSR), a molecular rearrangement that allows B cells to switch from expressing IgM and IgD to a secondary antibody heavy chain isotype such as IgG, IgA or IgE. Secondary antibody isotypes provide the adaptive immune system with distinct effector functions to optimally combat various pathogens. CSR occurs between repetitive DNA elements within the immunoglobulin heavy chain (Igh) locus, termed switch (S) regions and requires the DNA-modifying enzyme activation-induced cytidine deaminase (AID)...
April 1, 2017: International Immunology
https://www.readbyqxmd.com/read/28533409/inducible-ctcf-insulator-delays-the-igh-3-regulatory-region-mediated-activation-of-germline-promoters-and-alters-class-switching
#20
Fatima-Zohra Braikia, Chloé Oudinet, Dania Haddad, Zeliha Oruc, Domenico Orlando, Audrey Dauba, Marc Le Bert, Ahmed Amine Khamlichi
Class switch recombination (CSR) plays an important role in adaptive immune response by enabling mature B cells to switch from IgM expression to the expression of downstream isotypes. CSR is preceded by inducible germline (GL) transcription of the constant genes and is controlled by the 3' regulatory region (3'RR) in a stimulus-dependent manner. Why the 3'RR-mediated up-regulation of GL transcription is delayed to the mature B-cell stage is presently unknown. Here we show that mice devoid of an inducible CTCF binding element, located in the α constant gene, display a marked isotype-specific increase of GL transcription in developing and resting splenic B cells and altered CSR in activated B cells...
June 6, 2017: Proceedings of the National Academy of Sciences of the United States of America
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