Crosstalk Between Circulating Follicular T Helper Cells and Regulatory B Cells in Children With Extrinsic Atopic Dermatitis

Atopic dermatitis (AD) in early childhood is often the initial manifestation of allergic disease associated with high IgE. Accumulating evidences show that follicular helper T (Tfh) cells play a critical role in promoting B cell differentiation and IgE production, human regulatory B (Breg) cells participate in immunomodulatory processes and inhibition of allergic inflammation. However, the roles and interactions between IL-10-producing Breg cells and Tfh cells in childhood AD are unclear. In this study, we found that the percentage of CD19+IL-10+ Breg cells in children with extrinsic AD was significantly lower than that in age-matched healthy controls, and that it correlated negatively with enhanced CD4+CXCR5+PD-1+ICOS+ circulating Tfh cell responses and increased disease activity; however, there was no significant correlation with serum total IgE levels. A co-culture system revealed that Breg cells from patients with extrinsic AD cannot effectively inhibit differentiation of Tfh cells in an IL-10 dependent manner. Abnormal pSTAT3 signaling induced via Toll-like receptors (TLR), but not the B-cell receptor (BCR) signaling, might contribute to the defect of Breg cells in AD. Taken together, these observations demonstrate an important role for IL-10-producing Breg cells in inhibiting Tfh cell differentiation, and suggest that they may participate in the pathogenesis of AD.

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The Human (ΨL+μ−) proB Complex: Cell Surface Expression and Biochemical Structure of a Putative Transducing Receptor

Blood ◽

10.1182/blood.v93.12.4336 ◽

1999 ◽

Vol 93 (12) ◽

pp. 4336-4346 ◽

Cited By ~ 26

Author(s):

Bénédicte Lemmers ◽

Laurent Gauthier ◽

Valérie Guelpa-Fonlupt ◽

Michel Fougereau ◽

Claudine Schiff

Keyword(s):

Cell Differentiation ◽

Cell Surface ◽

B Cell ◽

Critical Role ◽

Cell Receptor ◽

Surface Expression ◽

Leukemic Cells ◽

Cell Surface Expression ◽

B Cell Differentiation ◽

Cell Reactivity

Abstract The surrogate light chain (ΨL) associates with μ and Ig-Igβ chains to form the preB-cell receptor that plays a critical role in early B-cell differentiation. Discrepancies exist in human concerning the existence of ΨL+μ− proB cells and the biochemical structure of such a proB-cell complex remains elusive. Among new antihuman VpreB monoclonal antibodies (MoAbs), 5 of the γκ isotype bound to recombinant and native VpreB protein with high affinity. They recognized 4 discrete epitopes, upon which 2 were in the extra-loop fragment. Such MoAbs detected the ΨL at the cell surface of either preB or on both proB and preB cells. The previously reported SLC1/SLC2 MoAbs recognize a conformational epitope specific for the μ/ΨL association in accordance with their preB-cell reactivity. Using the proB/preB 4G7 MoAb, ΨL cell surface expression was detected on normal bone marrow, not only on CD34−CD19+ preB but also on CD34+CD19+ proB cells. Futhermore, this MoAb identified ΨL+μ− fresh proB leukemic cells of the TEL/AML1 type. Biochemical studies showed that, at the proB stage, the ΨL is associated noncovalently with two proteins of 105 and 130 kD. Triggering of this complex induces intracellular Ca2+ flux, suggesting that the ΨL may be involved in a new receptor at this early step of the B-cell differentiation.

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The Human (ΨL+μ−) proB Complex: Cell Surface Expression and Biochemical Structure of a Putative Transducing Receptor

Blood ◽

10.1182/blood.v93.12.4336.412k28_4336_4346 ◽

1999 ◽

Vol 93 (12) ◽

pp. 4336-4346 ◽

Cited By ~ 1

Author(s):

Bénédicte Lemmers ◽

Laurent Gauthier ◽

Valérie Guelpa-Fonlupt ◽

Michel Fougereau ◽

Claudine Schiff

Keyword(s):

Cell Differentiation ◽

Cell Surface ◽

B Cell ◽

Critical Role ◽

Cell Receptor ◽

Surface Expression ◽

Leukemic Cells ◽

Cell Surface Expression ◽

B Cell Differentiation ◽

Cell Reactivity

The surrogate light chain (ΨL) associates with μ and Ig-Igβ chains to form the preB-cell receptor that plays a critical role in early B-cell differentiation. Discrepancies exist in human concerning the existence of ΨL+μ− proB cells and the biochemical structure of such a proB-cell complex remains elusive. Among new antihuman VpreB monoclonal antibodies (MoAbs), 5 of the γκ isotype bound to recombinant and native VpreB protein with high affinity. They recognized 4 discrete epitopes, upon which 2 were in the extra-loop fragment. Such MoAbs detected the ΨL at the cell surface of either preB or on both proB and preB cells. The previously reported SLC1/SLC2 MoAbs recognize a conformational epitope specific for the μ/ΨL association in accordance with their preB-cell reactivity. Using the proB/preB 4G7 MoAb, ΨL cell surface expression was detected on normal bone marrow, not only on CD34−CD19+ preB but also on CD34+CD19+ proB cells. Futhermore, this MoAb identified ΨL+μ− fresh proB leukemic cells of the TEL/AML1 type. Biochemical studies showed that, at the proB stage, the ΨL is associated noncovalently with two proteins of 105 and 130 kD. Triggering of this complex induces intracellular Ca2+ flux, suggesting that the ΨL may be involved in a new receptor at this early step of the B-cell differentiation.

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MAZ Is a Substrate for the Deubiquitinating Enzyme DUB1

Blood ◽

10.1182/blood.v116.21.3913.3913 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3913-3913

Author(s):

Yong-Soo Kim ◽

Dong-Mi Shin ◽

Hongsheng Wang ◽

Herbert Morse

Keyword(s):

Cell Differentiation ◽

B Cell ◽

Half Life ◽

Conflicts Of Interest ◽

Immunoblot Analysis ◽

Dependent Manner ◽

B Cell Differentiation ◽

Deubiquitinating Enzymes ◽

Transfected Cells

Abstract Abstract 3913 Ubiquitination is a fundamental mechanism of signal transduction that regulates immune responses and many other biological processes. Similar to phosphorylation, ubiquitination is a reversible process that is counter-regulated by ubiquitinating enzymes and deubiquitinating enzymes (DUBs). DUB1 has been identified as a member of a subfamily of deubiquitinating enzymes that are induced by Interleukin-3 (IL-3) in Ba/F3 cells. Recently, we've known that DUB1 is expressed in some pro-B and pre-B cell lines and is differentially regulated during normal B cell differentiation with highest expression in small pre-B cells. To understand the functional role of DUB1 in early B cell development, we identified a transcription factor, MAZ, as an interacting partner or substrate of DUB1 in the Abelson-transformed 220-8 pro-B cell line by using a retrovirus-based protein-fragment complementation assay (RePCA) screen. MAZ has been identified as a critical regulator of p21 gene induction, which controls cell cycle progression in synovial fibroblast cells. Immunoprecipitation and immunoblot analysis confirmed that MAZ and DUB1 interact with each other in cells. DUB1 expression significantly increased the steady-state cellular levels of MAZ. Notably, the half-life of MAZ in the pEGFP-DUB1-transfected cells was significantly increased by DUB1 expression, whereas the half-life of MAZ in the mock-transfected cells was less than 1 hr. These data therefore demonstrate that DUB1 specifically stabilizes MAZ in vivo. We found that the overexpressed MAZ was polyubiquitinated and that the polyubiquitinated MAZ was the substrate for proteasome inhibitor MG132 caused a robust increase of MAZ polyubiquitination. Overexpression of DUB1 in 293T cells caused a decrease of MAZ polyubiquitination in a DUB1 dose-dependent manner. Taken together, these results indicate that DUB1 mediate the ubiquitination-dependent degradation of MAZ. Other study shows that the DUB1 targets both K-48 and K-63 linked ubiquitination suggesting that it may be involved in both protein degradative and non-degradative functions during early B cell differentiation. Disclosures: No relevant conflicts of interest to declare.

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Increased Frequency of Pre–Pro B Cells in the Bone Marrow of New Zealand Black (NZB) Mice: Implications for aDevelopmental Block in B Cell Differentiation

Developmental Immunology ◽

10.1080/1044667021000003961 ◽

2002 ◽

Vol 9 (1) ◽

pp. 35-45 ◽

Cited By ~ 7

Author(s):

Zhe-Xiong Lian ◽

Hiroto Kita ◽

Tomoyuki Okada ◽

Tom Hsu ◽

Leonard D. Shultz ◽

...

Keyword(s):

New Zealand ◽

Cell Differentiation ◽

B Cells ◽

B Cell ◽

Cell Receptor ◽

Cell Development ◽

B Cell Development ◽

B Cell Differentiation ◽

Differentiation Markers ◽

Cell Stage

Reductions in populations of both Pre-B cell (Hardy fractions D) and Pro-B cells (Hardy fractions B–C) have been described in association with murine lupus. Recent studies of B cell populations, based on evaluation of B cell differentiation markers, now allow the enumeration and enrichment of other stage specific precursor cells. In this study we report detailed analysis of the ontogeny of B cell lineage subsets in New Zealand black (NZB) and control strains of mice. Our data suggest that B cell development in NZB mice is partially arrested at the fraction A Pre–Pro B cell stage. This arrest at the Pre-Pro B cell stage is secondary to prolonged lifespan and greater resistance to spontaneous apoptosis. In addition, expression of the gene encoding the critical B cell development transcription factor BSAP is reduced in the Pre–Pro B cell stage in NZB mice. This impairment may influence subsequent B cell development to later stages, and thereby accounts for the down-regulation of the B cell receptor componentIgα(mb-1). Furthermore, levels of expression of theRug2, λ5andIgβ(B29) genes are also reduced in Pre–Pro B cells of NZB mice. The decreased frequency of precursor B cells in the Pre–Pro B cell population occurs at the most primitive stage of B cell differentiation.

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Loss of juxtaposition of RAG-induced immunoglobulin DNA ends is implicated in the precursor B-cell differentiation defect in NBS patients

Blood ◽

10.1182/blood-2009-10-250514 ◽

2010 ◽

Vol 115 (23) ◽

pp. 4770-4777 ◽

Cited By ~ 22

Author(s):

Mirjam van der Burg ◽

Malgorzata Pac ◽

Magdalena A. Berkowska ◽

Bozenna Goryluk-Kozakiewicz ◽

Anna Wakulinska ◽

...

Keyword(s):

Cell Differentiation ◽

B Cell ◽

Gene Segment ◽

Cell Receptor ◽

Nijmegen Breakage Syndrome ◽

Immunoglobulin Gene ◽

B Cell Differentiation ◽

Receptor Repertoire ◽

Recombination Activating Gene ◽

Dna Ends

Abstract The Nijmegen breakage syndrome (NBS) is a rare inherited condition, characterized by microcephaly, radiation hypersensitivity, chromosomal instability, an increased incidence of (mostly) lymphoid malignancies, and immunodeficiency. NBS is caused by hypomorphic mutations in the NBN gene (8q21). The NBN protein is a subunit of the MRN (Mre11-Rad50-NBN) nuclear protein complex, which associates with double-strand breaks. The immunodeficiency in NBS patients can partly be explained by strongly reduced absolute numbers of B lymphocytes and T lymphocytes. We show that NBS patients have a disturbed precursor B-cell differentiation pattern and significant disturbances in the resolution of recombination activating gene-induced IGH breaks. However, the composition of the junctional regions as well as the gene segment usage of the reduced number of successful immunoglobulin gene rearrangements were highly similar to healthy controls. This indicates that the NBN defect leads to a quantitative defect in V(D)J recombination through loss of juxtaposition of recombination activating gene-induced DNA ends. The resulting reduction in bone marrow B-cell efflux appeared to be partly compensated by significantly increased proliferation of mature B cells. Based on these observations, we conclude that the quantitative defect will affect the B-cell receptor repertoire, thus contributing to the observed immunodeficiency in NBS patients.

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Ikaros Mutation Confers Integrin-Dependent Survival Of Pre-B Cells and Progression To Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v122.21.1259.1259 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1259-1259

Author(s):

Nilamani Jena ◽

Ila Joshi ◽

Toshimi Yoshida ◽

Xiaoqing Qi ◽

Jiangwen Zhang ◽

...

Keyword(s):

Cell Differentiation ◽

B Cells ◽

Dna Binding ◽

B Cell ◽

Focal Adhesion ◽

Lymphoblastic Leukemia ◽

Cell Receptor ◽

Mapk Signaling ◽

Dominant Negative ◽

B Cell Differentiation

Abstract Deletion of the IKAROS DNA-binding domain generates dominant-negative isoforms that interfere with the transcriptional activity of the IKAROS family and correlate with poor prognosis in human precursor B cell acute lymphoblastic leukemias (B-ALL). In this study, we defined the role of the Ikaros family during pre-B cell differentiation, the stage from which human B-ALLs arise, by conditionally inactivating IKAROS DNA binding in the immediate precursors of pre-B cells in mice. We demonstrate a novel niche-dependent phase in early pre-B cell differentiation that supports self-renewal and proliferative expansion. Expression of dominant-negative IKAROS arrests cells in this state by augmenting integrin and MAPK signaling and attenuating pre-B cell receptor signaling and differentiation. Up-regulated genes in Ikaros mutant pre-B cells were highly enriched in pathways involved in focal adhesion and remodeling of the actin cytoskeleton. The mutant pre-B cells had increased β1 integrin-mediated adhesion and elevated levels of activated focal adhesion kinase (FAK), whereas treatment with a small molecule FAK inhibitor greatly reduced pre-B cell stromal adhesion and selectively induced apoptosis in Ikaros mutant but not WT pre-B cells. Transplantation of polyclonal Ikaros mutant pre-B cells into recipient mice resulted in long-latency oligoclonal pre-B-ALL, demonstrating that loss of IKAROS contributes to multistep B-leukemogenesis. The highly proliferative and aberrantly self-renewing phenotype of Ikaros-deficient pre-B cells illuminates mechanisms underlying human IKAROS mutant B-ALL and suggests new therapeutic strategies for treatment of this aggressive leukemia. Disclosures: Van Etten: Bristol Myers Squibb: Consultancy; Deciphera Pharmaceuticals: Consultancy; TEVA Pharmaceuticals: Consultancy, Research Funding.

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