A unique B2 B cell subset in the intestine

Over 80% of the body's activated B cells are located in mucosal sites, including the intestine. The intestine contains IgM+ B cells, but these cells have not been characterized phenotypically or in terms of their developmental origins. We describe a previously unidentified and unique subset of immunoglobulin M+ B cells that present with an AA4.1−CD21−CD23− major histocompatibility complex class IIbright surface phenotype and are characterized by a low frequency of somatic hypermutation and the potential ability to produce interleukin-12p70. This B cell subset resides within the normal mucosa of the large intestine and expands in response to inflammation. Some of these intestinal B cells originate from the AA4.1+ immature B2 cell pool in the steady state and are also recruited from the recirculating naive B cell pool in the context of intestinal inflammation. They develop in an antigen-independent and BAFF-dependent manner in the absence of T cell help. Expansion of these cells can be induced in the absence of the spleen and gut-associated lymphoid tissues. These results describe the existence of an alternative pathway of B cell maturation in the periphery that gives rise to a tissue-specific B cell subset.

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EBV Transformation of Tonsil Germinal Centre B Cells Carrying Functionally Inactivated IgV Gene.

Blood ◽

10.1182/blood.v104.11.3248.3248 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3248-3248

Author(s):

Sridhar Chaganti ◽

Noelia Begue Pastor ◽

Mark T. Drayson ◽

Andy I. Bell ◽

Alan B. Rickinson

Keyword(s):

B Cells ◽

B Cell ◽

Somatic Hypermutation ◽

B Cell Lymphoma ◽

Affinity Maturation ◽

Germinal Centre ◽

Chain Gene ◽

Lymphoid Tissues ◽

Memory B Cell

Abstract Somatic hypermutation of immunoglobulin (Ig) gene sequences in the germinal centres of lymphoid tissues is necessary for affinity maturation of B cell responses to antigen challenge. This process generates a few clones with improved affinity that are selected into B cell memory and many clones with other non favourable Ig mutations, including some cells with functionally inactivated Ig gene that normally die by apoptosis. It is postulated that infection with Epstein-Barr virus (EBV), a B lymphotropic agent linked to several types of B cell lymphoma, can rescue germinal centre cells with unfavourable mutations. This creates a pool of infected cells at greater risk of developing into lymphomas. In the present work, CD38+ germinal centre B cells were separated from tonsil by negative selection for IgD and CD39. Peripheral blood naïve and memory B cell subpopulations were FACS sorted as IgD+, CD27− and IgD−, CD27+ fractions respectively. These cells were infected with EBV (B95.8 strain) in vitro and seeded at limiting dilutions onto fibroblast feeders. EBV transformed lymphoblastoid cell lines (LCLs) from such cultures were analysed for surface Ig phenotype. Naïve B cell transformants were consistently IgM+, IgD+. Memory B cell transformants were IgM+ in some cases but more frequently IgG+ or IgA+. Germinal centre transformants showed the same spectrum of surface Ig phenotypes as memory cell transformants but in addition we identified six germinal centre derived LCLs which were consistently surface Ig negative. Sequencing from these lines confirmed that in at least three cases EBV had rescued cells with functionally inactivated Ig heavy chain gene.

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Human germinal center B cells express the apoptosis-inducing genes Fas, c-myc, P53, and Bax but not the survival gene bcl-2.

Journal of Experimental Medicine ◽

10.1084/jem.183.3.971 ◽

1996 ◽

Vol 183 (3) ◽

pp. 971-977 ◽

Cited By ~ 156

Author(s):

H Martinez-Valdez ◽

C Guret ◽

O de Bouteiller ◽

I Fugier ◽

J Banchereau ◽

...

Keyword(s):

Cell Cycle ◽

B Cells ◽

B Cell ◽

Germinal Center ◽

Somatic Hypermutation ◽

Cell Subset ◽

Variable Region ◽

Negative Regulator ◽

Memory B Cell ◽

Survival Gene

During T cell-dependent antibody responses, B cells within germinal centers (GC) alter the affinity of their antigen receptor by introducing somatic mutations into variable region of immunoglobulin (IgV) genes. During this process, GC B cells are destined to die unless positively selected by antigens and CD40-ligand. To understand survival/death control of germinal center B cell, the expression of four apoptosis-inducing genes, Fas, c-myc, Bax, and P53, together with the survival gene bcl-2, has been analyzed herein among purified tonsillar naive, GC, and memory B cells. IgD+CD38- naive B cells were separated into CD23- (mature B cell [Bm]1) subset and CD23+ (Bm2), IgD-CD38+ GC B cells were separated into subsets of CD77+ centroblasts (Bm3) and CD77- centrocytes (Bm4), whereas IgD-CD38- cells represented the Bm5 memory B cell subset. Sequence analysis of IgV region genes indicated that somatic hypermutation was triggered in the Bm3 centroblast subset. Here we show that bcl-2 is only detectable with naive (Bm1 and 2) and memory B cell (Bm5) subsets, whereas all four apoptosis-inducing genes were most significantly expressed within GC B cells. Fas was equally expressed in Bm3 centroblasts and Bm4 centrocytes, whereas Bax was most significantly expressed in Bm4 centrocytes. c-myc, a positive regulator of cell cycle, was most significantly expressed in proliferating Bm3 centroblasts, whereas P53, a negative regulator of cell cycle, was most signficantly expressed in nonproliferating Bm4 centrocytes. The present results indicate that the survival/death of GC B cells are regulated by the up- and downregulation of multiple genes, among which the expression of c-myc and P53 in the absence of bcl-2 may prime the proliferating Bm3 centroblasts and nonproliferating Bm4 centrocytes to apoptosis.

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Blimp-1-Dependent Repression of Pax-5 Is Required for Differentiation of B Cells to Immunoglobulin M-Secreting Plasma Cells

Molecular and Cellular Biology ◽

10.1128/mcb.22.13.4771-4780.2002 ◽

2002 ◽

Vol 22 (13) ◽

pp. 4771-4780 ◽

Cited By ~ 292

Author(s):

Kuo-I Lin ◽

Cristina Angelin-Duclos ◽

Tracy C. Kuo ◽

Kathryn Calame

Keyword(s):

B Cells ◽

B Cell ◽

B Lymphocyte ◽

Critical Role ◽

Cell Lineage ◽

Immunoglobulin M ◽

Dependent Manner ◽

Plasmacytic Differentiation

ABSTRACT B-cell lineage-specific activator protein (BSAP), encoded by the Pax-5 gene, is critical for B-cell lineage commitment and B-cell development but is not expressed in terminally differentiated B cells. We demonstrate a direct connection between BSAP and B-lymphocyte-induced maturation protein 1 (Blimp-1), a transcriptional repressor that is sufficient to drive plasmacytic differentiation. Blimp-1 binds a site on the Pax-5 promoter in vitro and in vivo and represses the Pax-5 promoter in a binding-site-dependent manner. By ectopically expressing Blimp-1 or a competitive inhibitor of Blimp-1, we show that Blimp-1 is both necessary and sufficient to repress Pax-5 during plasmacytic differentiation of primary splenic B cells. Blimp-1-dependent repression of Pax-5 is sufficient to regulate BSAP targets CD19 and J chain and is necessary but not sufficient to induce XBP-1. We further show that repression of Pax-5 is required for Blimp-1 to drive differentiation of splenocytes to immunoglobulin M-secreting cells. Thus, repression of Pax-5 plays a critical role in the Blimp-1-dependent program of plasmacytic differentiation.

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SYK regulates B-cell migration by phosphorylation of the F-actin interacting protein SWAP-70

Blood ◽

10.1182/blood-2010-07-295659 ◽

2011 ◽

Vol 117 (5) ◽

pp. 1574-1584 ◽

Cited By ~ 33

Author(s):

Glen Pearce ◽

Tatsiana Audzevich ◽

Rolf Jessberger

Keyword(s):

Cell Migration ◽

B Cells ◽

B Cell ◽

Cell Polarization ◽

Actin Binding ◽

Lymphoid Tissues ◽

Dependent Manner ◽

Interacting Protein

Abstract B-cell migration into and within lymphoid tissues is not only central to the humoral immune response but also for the development of malignancies and autoimmunity. We previously demonstrated that SWAP-70, an F-actin-binding, Rho GTPase-interacting protein strongly expressed in activated B cells, is necessary for normal B-cell migration in vivo. SWAP-70 regulates integrin-mediated adhesion and cell attachment. Here we show that upon B-cell activation, SWAP-70 is extensively posttranslationally modified and becomes tyrosine phosphorylated by SYK at position 517. This phosphorylation inhibits binding of SWAP-70 to F-actin. Phospho-site mutants of SWAP-70 disrupt B-cell polarization in a dominant-negative fashion in vitro and impair migration in vivo. After CXCL12 stimulation of B cells SYK becomes activated and SWAP-70 is phosphorylated in a SYK-dependent manner. Use of the highly specific SYK inhibitor BAY61-3606 showed SYK activity is necessary for normal chemotaxis and B-cell polarization in vitro and for entry of B cells into lymph nodes in vivo. These findings demonstrate a novel requirement for SYK in migration and polarization of naive recirculating B cells and show that SWAP-70 is an important target of SYK in this pathway.

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Autoantibody-associated cross-reactive idiotype-bearing human B lymphocytes: distribution and characterization, including Ig VH gene and CD5 antigen expression

Blood ◽

10.1182/blood.v78.6.1503.1503 ◽

1991 ◽

Vol 78 (6) ◽

pp. 1503-1515 ◽

Cited By ~ 18

Author(s):

G Inghirami ◽

DR Foitl ◽

A Sabichi ◽

BY Zhu ◽

DM Knowles

Keyword(s):

B Cells ◽

B Cell ◽

B Lymphocytes ◽

Cell Subset ◽

Antigen Expression ◽

Lymphocytic Leukemia ◽

Cell Subpopulation ◽

Lymphoid Tissues ◽

Vh Gene

Abstract Monoclonal antibodies (MoAbs) specific for autoantibody associated cross-reactive idiotypes (CRIs) frequently recognize the Igs of neoplastic B cells in patients with chronic lymphocytic leukemia (CLL) and/or Waldenstrom's macroglobulinemia. Very little is known regarding the normal B cells expressing CRIs (CRI-positive B cells). Using a variety of MoAbs against CRIs we investigated the distribution and topographic localization of CRI-positive B cells in normal adult human lymphoid tissues. We found that CRI-positive B cells represent a significant B-cell subpopulation expressing surface IgM (greater than 90%), IgG (approximately 5%), or IgA (approximately 2%). CRI-positive B cells are homogeneously distributed throughout all lymphoid tissues, accounting for 10% to 15% of all B lymphocytes, with the exception of the thymus, in which they represent the predominant B cell population. Immunophenotypic studies showed (1) that a small subpopulation (3.7% +/- 0.8%) of CRI-positive B cells are activated in vivo, based on CD25 and CD38 antigen expression; and (2) that approximately 50% of CRI-positive B cells express the 67-Kd pan-T-lymphocyte CD5 antigen, suggesting that the CRI-positive B-cell subset and the recently described CD5-positive B-cell subset are closely related. This hypothesis is supported by the fact that CRI-positive B cells produce oligo or polyreactive Igs, which are a characteristic feature of CD5-positive B cells, and also by the fact that both B-cell subpopulations appear to use similar and restricted Ig VH gene family members.

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CCL19 Induced Responses Are Differentially Regulated by Atypical Chemokine Receptor CRAM and Its Classical Chemokine Receptor CCR7 in B-CLL Cells

Blood ◽

10.1182/blood.v118.21.4896.4896 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4896-4896 ◽

Cited By ~ 1

Author(s):

Nathalie Burger ◽

Andrea Haerzschel ◽

Marion Leick ◽

Tanja Nicole Hartmann ◽

Julie Catusse ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Chemokine Receptor ◽

Chemokine Receptors ◽

Conflicts Of Interest ◽

Maturation Stage ◽

Lymphoid Tissues ◽

Dependent Manner ◽

Chemokine Ligand ◽

Cell Layers

Abstract Abstract 4896 Introduction: Chemokines are known to play an important role in the migration and survival of B-CLL cells. The non-signalling chemokine receptors, including DARC, D6 and CCX-CKR, have recently been shown to be involved in chemokine clearance and activity regulation. The human chemokine receptor CRAM is the most recently identified member of this atypical group. CRAM is expressed on B cells in a maturation-stage dependent manner, and to variable degrees on B-CLL cells. We have recently shown that it competitively binds CCL19 and that this binding is not followed by classical chemokine responses. CCL19 and its signalling receptor CCR7 are centrally involved in B cell localisation and maturation within the secondary lymphoid tissues. CCR7 is also highly expressed on B cells from CLL patients and mediates migration towards its ligands CCL19 and CCL21 which have been shown to be present at higher concentrations in serum of patients with lymphadenopathia compared to patients without. In this study we investigate the influence of CRAM on the CCL19 dependent responses of B-CLL cells and potential correlations to clinical data with a specific focus on lymphadenopathia. Results: We demonstrate that B cells from patients with B-CLL present high, but variable degrees of CCR7 and CRAM expression. Patients with compared to patients without lymphadenopathia show a higher CRAM expression level whereas the CCR7 expression is not significantly different. In single samples showing extremly high CRAM expression the migration towards CCL19 is reduced compared to patients with lower CRAM expression. These observations confirm results in the B-CLL cell line MEC-1 showing increased migration toward CCL19 when CRAM expression is reduced using CRAM-siRNA. On the other hand, CRAM seems to be a chemokine presenter as we can show that it does not degrade its chemokine ligand but presents it on the surface of polarised cell layers. Thus, we assume that CRAM plays a role for cell migration, possibly transmigration and cell localisation within lymph nodes of B-CLL cells. Conclusions: We show that CRAM can act as an integrator of different recruitment and activation factors. It is associated to CCR7 driven recruitment of B cells by regulating CCL19 availability. Expression of CRAM differs in B cell malignancies for which CCL19 and CCL21 have already been shown to be implicated in lymphadenopathia. We therefore suggest that CRAM is an additional player in the localisation and differentiation/maturation processes of malignant B cells of B-CLL patients. Disclosures: No relevant conflicts of interest to declare.

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Autoantibody-associated cross-reactive idiotype-bearing human B lymphocytes: distribution and characterization, including Ig VH gene and CD5 antigen expression

Blood ◽

10.1182/blood.v78.6.1503.bloodjournal7861503 ◽

1991 ◽

Vol 78 (6) ◽

pp. 1503-1515

Author(s):

G Inghirami ◽

DR Foitl ◽

A Sabichi ◽

BY Zhu ◽

DM Knowles

Keyword(s):

B Cells ◽

B Cell ◽

B Lymphocytes ◽

Cell Subset ◽

Antigen Expression ◽

Lymphocytic Leukemia ◽

Cell Subpopulation ◽

Lymphoid Tissues ◽

Vh Gene

Monoclonal antibodies (MoAbs) specific for autoantibody associated cross-reactive idiotypes (CRIs) frequently recognize the Igs of neoplastic B cells in patients with chronic lymphocytic leukemia (CLL) and/or Waldenstrom's macroglobulinemia. Very little is known regarding the normal B cells expressing CRIs (CRI-positive B cells). Using a variety of MoAbs against CRIs we investigated the distribution and topographic localization of CRI-positive B cells in normal adult human lymphoid tissues. We found that CRI-positive B cells represent a significant B-cell subpopulation expressing surface IgM (greater than 90%), IgG (approximately 5%), or IgA (approximately 2%). CRI-positive B cells are homogeneously distributed throughout all lymphoid tissues, accounting for 10% to 15% of all B lymphocytes, with the exception of the thymus, in which they represent the predominant B cell population. Immunophenotypic studies showed (1) that a small subpopulation (3.7% +/- 0.8%) of CRI-positive B cells are activated in vivo, based on CD25 and CD38 antigen expression; and (2) that approximately 50% of CRI-positive B cells express the 67-Kd pan-T-lymphocyte CD5 antigen, suggesting that the CRI-positive B-cell subset and the recently described CD5-positive B-cell subset are closely related. This hypothesis is supported by the fact that CRI-positive B cells produce oligo or polyreactive Igs, which are a characteristic feature of CD5-positive B cells, and also by the fact that both B-cell subpopulations appear to use similar and restricted Ig VH gene family members.

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Continuous anti-interleukin 10 antibody administration depletes mice of Ly-1 B cells but not conventional B cells.

Journal of Experimental Medicine ◽

10.1084/jem.175.5.1213 ◽

1992 ◽

Vol 175 (5) ◽

pp. 1213-1220 ◽

Cited By ~ 133

Author(s):

H Ishida ◽

R Hastings ◽

J Kearney ◽

M Howard

Keyword(s):

B Cells ◽

B Cell ◽

Cell Subset ◽

Keyhole Limpet Hemocyanin ◽

Interleukin 10 ◽

Immunoglobulin M ◽

Ifn Gamma ◽

Paracrine Growth Factor

Ly-1 B cells have the distinctive property of continuous self-replenishment and, as we have shown previously, can be further distinguished from conventional B cells on the basis of greatly elevated constitutive and inducible production of the recently described cytokine interleukin 10 (IL-10). To test the possibility that IL-10 acts as either an autocrine or paracrine growth factor for Ly-1 B cells, we treated mice continuously from birth to 8 wk of age with a monoclonal rat IgM antibody that specifically neutralizes mouse IL-10. Mice treated in this way lacked peritoneal-resident Ly-1 B cells, contained greatly reduced serum immunoglobulin M levels, and were unable to generate significant in vivo antibody responses to intraperitoneal injections of alpha 1,3-dextran or phosphorylcholine, antigens for which specific B cells reside in the Ly-1 B cell subset. In contrast, conventional splenic B cells of anti-IL-10-treated mice were normal with respect to total numbers, phenotype, and in vitro responsiveness to B cell mitogens and the thymus-dependent antigen trinitrophenyl-keyhole limpet hemocyanin (TNP-KLH). The mechanism of Ly-1 B cell depletion appeared to be related to elevation of endogenous interferon gamma (IFN-gamma) levels in anti-IL-10-treated mice, since coadministration of neutralizing anti-IFN-gamma antibodies substantially restored the number of peritoneal-resident Ly-1 B cells in these mice. These results implicate IL-10 as a regulator of Ly-1 B cell development, and identify a procedure to specifically deplete Ly-1 B cells, thereby allowing further evaluation of the role of these cells in the immune system.

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Deregulated Bcl-2-immunoglobulin transgene expands a resting but responsive immunoglobulin M and D-expressing B-cell population.

Molecular and Cellular Biology ◽

10.1128/mcb.10.5.1901 ◽

1990 ◽

Vol 10 (5) ◽

pp. 1901-1907 ◽

Cited By ~ 143

Author(s):

T J McDonnell ◽

G Nunez ◽

F M Platt ◽

D Hockenberry ◽

L London ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cell Survival ◽

Gradient Centrifugation ◽

Cell Subset ◽

Immunoblot Analysis ◽

Immunoglobulin M ◽

Color Flow ◽

S1 Nuclease

We characterized the basis for the follicular lymphoproliferation in transgenic mice bearing a Bcl-2-immunoglobulin (Bcl-2-Ig) minigene representing the t(14;18) of human follicular lymphoma. Discriminatory S1 nuclease protection assays revealed that the Bcl-2-Ig transgene was overexpressed relative to endogenous mouse Bcl-2 in spleen and thymus. Western (immunoblot) analysis demonstrated the overproduction of the human 25-kilodalton Bcl-2 protein, which arose from the transgene, in spleen, thymus, and the expanded B-cell subset. Despite the generalized lymphoid pattern of deregulation, two-color flow cytometry and density gradient centrifugation indicated that the expanded lymphocytes were predominantly small, resting B cells coexpressing B220, immunoglobulin M (IgM), IgD, Ia, and kappa. Cell cycle analysis confirmed that about 97% of these expanded B cells reside in G0/G1. An extensive characterization of transgenic lines revealed a fourfold excess of IgM-IgD-expressing B cells in spleen and dramatically increased numbers in bone marrow. While resting, these cells proliferated in response to lipopolysaccharide and anti-IgM and demonstrated normal B-cell colony formation in soft agar. Moreover, these B cells, which demonstrated an extended survival in vitro even in the absence of stroma, were also resting in G0, yet were capable of proliferative responses. These findings provide consistent evidence that the accumulation of B cells after Bcl-2 overproduction is secondary to prolonged cell survival and not increased cell cycling. This suggests a unique role for Bcl-2 as a proto-oncogene that enhances cell survival independent of promoting cell division.

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