scholarly journals B cell–intrinsic deficiency of the Wiskott-Aldrich syndrome protein (WASp) causes severe abnormalities of the peripheral B-cell compartment in mice

Blood ◽  
2012 ◽  
Vol 119 (12) ◽  
pp. 2819-2828 ◽  
Author(s):  
Mike Recher ◽  
Siobhan O. Burns ◽  
Miguel A. de la Fuente ◽  
Stefano Volpi ◽  
Carin Dahlberg ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Plasma Cells ◽  
Autoantibody Production ◽  
Marginal Zone B Cells ◽  
Wiskott Aldrich Syndrome ◽  
Germinal Center B Cells

Abstract Wiskott Aldrich syndrome (WAS) is caused by mutations in the WAS gene that encodes for a protein (WASp) involved in cytoskeleton organization in hematopoietic cells. Several distinctive abnormalities of T, B, and natural killer lymphocytes; dendritic cells; and phagocytes have been found in WASp-deficient patients and mice; however, the in vivo consequence of WASp deficiency within individual blood cell lineages has not been definitively evaluated. By conditional gene deletion we have generated mice with selective deficiency of WASp in the B-cell lineage (B/WcKO mice). We show that this is sufficient to cause a severe reduction of marginal zone B cells and inability to respond to type II T-independent Ags, thereby recapitulating phenotypic features of complete WASp deficiency. In addition, B/WcKO mice showed prominent signs of B-cell dysregulation, as indicated by an increase in serum IgM levels, expansion of germinal center B cells and plasma cells, and elevated autoantibody production. These findings are accompanied by hyperproliferation of WASp-deficient follicular and germinal center B cells in heterozygous B/WcKO mice in vivo and excessive differentiation of WASp-deficient B cells into class-switched plasmablasts in vitro, suggesting that WASp-dependent B cell–intrinsic mechanisms critically contribute to WAS-associated autoimmunity.

scholarly journals Germinal center B cells lack homing receptors necessary for normal lymphocyte recirculation.

1983 ◽  
Vol 157 (3) ◽  
pp. 813-827 ◽  
Author(s):  
R A Reichert ◽  
W M Gallatin ◽  
I L Weissman ◽  
E C Butcher
Keyword(s):  
T Cells ◽  
B Cells ◽  
Germinal Center ◽  
Plasma Cells ◽  
Lymphoid Organs ◽  
Vitro Assay ◽  
Peripheral Node ◽  
Germinal Center B Cells

Germinal center B cells (GCLC) are a discrete population of antigen-activated lymphoblasts that lack surface IgD and express abundant cell surface binding sites for peanut agglutinin (PNA). These phenotypic features render GCLC easily distinguishable from nearly all plasma cells, T cells, and unstimulated B cells, and have enabled us to identify and isolate GCLC from antigen-stimulated murine lymphoid organs. We have examined the migratory properties of these lymphoblasts in (a) short-term in vivo homing studies, and (b) an in vitro assay of lymphocyte binding to post-capillary, high endothelial venules (HEV) in frozen sections of Peyer's patches and peripheral lymph nodes. In the in vivo experiments, intravenously injected GCLC failed to migrate in significant numbers to peripheral lymphoid organs in comparison with T cells or IgD+ B cells. In the in vitro binding assay, GCLC did not adhere to HEV in either Peyer's patch or peripheral node sections. A variety of factors, such as preferential sequestration in the liver, may operate in vivo to influence the localization of these cells. However, their nearly total failure to migrate into lymphoid organs can best be explained by their inability to recognize and adhere to the specialized HEV which normally mediate the emigration of recirculating lymphocytes from the blood into these sites. The concept that GCLC fail to express functional homing receptors for HEV has been further supported by studies using MEL-14, a monoclonal antibody that appears to recognize the lymphocyte surface receptor for peripheral node HEV: In contrast to most peripheral lymphocytes, GCLC fail to bind MEL-14. These migratory and endothelial-recognition properties of GCLC, when viewed in the context of the possible role of these cells as precursors of plasma cells and/or memory B cells, have led us to propose that the inability of GCLC to recognize HEV may be transient and related to a phase of sessile B cell differentiation.

scholarly journals Differential Regulation of Mouse B Cell Development by Transforming Growth Factor β1

2002 ◽  
Vol 9 (2) ◽  
pp. 86-95 ◽  
Author(s):  
Denise A. Kaminski ◽  
John J. Letterio ◽  
Peter D. Burrows
Keyword(s):  
B Cells ◽  
Growth Factor ◽  
B Cell ◽  
Transforming Growth Factor ◽  
Plasma Cells ◽  
Population Analysis ◽  
Cell Development ◽  
B Cell Development

Transforming growth factor β (TGFβ) can inhibit thein vitroproliferation, survival and differentiation of B cell progenitors, mature B lymphocytes and plasma cells. Here we demonstrate unexpected, age-dependent reductions in the bone marrow (BM) B cell progenitors and immature B cells in TGFβ1-/-mice. To evaluate TGFβ responsiveness during normal B lineage development, cells were cultured in interleukin 7 (IL7)±TGFβ. Picomolar doses of TGFβ1 reduced pro-B cell recoveries at every timepoint. By contrast, the pre-B cells were initially reduced in number, but subsequently increased compared to IL7 alone, resulting in a 4-fold increase in the growth rate for the pre-B cell population. Analysis of purified BM sub-populations indicated that pro-B cells and the earliest BP1-pre-B cells were sensitive to the inhibitory effects of TGFβ1. However, the large BP1+pre-B cells, although initially reduced, were increased in number at days 5 and 7 of culture. These results indicate that TGFβ1 is important for normal B cell developmentin vivo, and that B cell progenitors are differentially affected by the cytokine according to their stage of differentiation.

scholarly journals Telomerase activation in normal B lymphocytes and non-Hodgkin's lymphomas

Blood ◽  
1996 ◽  
Vol 88 (1) ◽  
pp. 222-229 ◽  
Author(s):  
KF Norrback ◽  
K Dahlenborg ◽  
R Carlsson ◽  
G Roos
Keyword(s):  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Telomerase Activity ◽  
Lymphoid Tissues ◽  
Low Grade ◽  
Malignant Lymphomas ◽  
Hodgkin's Lymphomas ◽  
Germinal Center B Cells

Abstract Activation of telomerase seems to be a prerequisite for immortalization and is found in permanent cell lines and most malignant tumors. Normal somatic cells are generally telomerase negative, except for bone marrow stem cells. Weak activity is also present in peripheral blood cells. In the present study strong telomerase activity was demonstrated in vivo in normal mature cells of the immune system, as well as in malignant lymphomas. Benign lymph nodes had lower telomerase activity than benign tonsils, which exhibited intermediate to high activity comparable with findings in malignant lymphomas. In benign tonsils the activity seemed to be restricted to germinal center B cells. In benign lymphoid tissues telomerase activity correlated with B-cell numbers and cell proliferation, but this was not observed in the lymphoma group. High- grade lymphomas exhibited higher levels of telomerase compared with low- grade cases. The data showed that in vivo activation of telomerase is a characteristic feature of germinal center B cells. Different signals for activation of telomerase are likely to exist, one of them being immune stimulation. The data suggest that telomerase activity in malignant lymphomas can be explained by an “induction and retention” model, ie, transformation occurs in a normal, mature B cell with reactivated telomerase, which is retained in the neoplastic clone.

Protein Signature of LMP1 Signaling in PTLDs Identifies and Mimics Inter/Perifollicular CD30+ EBV− B Blasts.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3251-3251
Author(s):  
Rita Shaknovich ◽  
Katia Basso ◽  
Govind Bhagat ◽  
Bachir Alobeid ◽  
Giorgio Cattoretti
Keyword(s):  
B Cells ◽  
B Cell ◽  
Plasma Cells ◽  
Cell Subset ◽  
Cellular Transformation ◽  
Cell Types ◽  
Marginal Zone B Cells ◽  
Latently Infected ◽  
Protein Signature

Abstract EBV-associated B-cell Post-Transpant Lymphoproliferative Disorders (PTLDs) represent a diverse group of lesions morphologically, in clinical presentation and behaviour, ranging from early reversible lesions to monomorphic aggressive lymphomas. Polymorphic cases, which represent the focus of our analysis, contain a mixture of cells in various EBV latency stages, defined by EBNA1, EBNA2 and LMP1 immunostaining. LMP1 is a key viral protein for cellular transformation and, analogously to CD40, engages TNF Receptor Associated Proteins and activates NF-kB and NF-kB-responsive genes. We analyzed the protein signature of LMP1 in PTLDs and non-PTLD tonsils by double staining for LMP1, CD30, CD20, Pax5 and signaling molecules. A remarkably conserved set of proteins, associated with LMP1/CD40 signaling and NF-kB activation is expressed both in the EBV-infected lymphoid population in polymorphic PTLDs and in a normal B-cell subset(s) in reactive tonsils. These proteins include highly expressed CD30, JunB, nuclear cRel, TRAF-1, Bcl-XL, MUM1, CCL22 and downregulated BCL6 and CD10. We observed that EBV infection, possibly through LMP1 and LMP2A signaling, results in varioius degrees of differentiation within the neoplastic clone. EBER+ terminally differentiated mucosa-associated IRTA-1+ marginal zone B-cells and CD138+ plasma cells were identified in most cases, including control post-transplant tonsils with no overt disease. We document for the first time in situ, in-vivo evidence of EBV latently infected post-Germinal Center B cells of marginal and plasma cell types in PTLDs. Polymorphic PTLD cases represent EBV-induced expansion of B cells, mimicking CD40L-like activated Peri/Interfollicular CD30+ normal B-cells.

scholarly journals Covalent Linkage of HIV-1 Trimers to Synthetic Liposomes Elicits Improved B Cell and Antibody Responses

2017 ◽  
Vol 91 (16) ◽  
Author(s):  
Shridhar Bale ◽  
Geraldine Goebrecht ◽  
Armando Stano ◽  
Richard Wilson ◽  
Takayuki Ota ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Neutralizing Antibodies ◽  
Tier 2 ◽  
Covalent Linkage ◽  
His Tag ◽  
Hiv 1

ABSTRACT We have demonstrated that a liposomal array of well-ordered trimers enhances B cell activation, germinal center formation, and the elicitation of tier-2 autologous neutralizing antibodies. Previously, we coupled well-ordered cleavage-independent NFL trimers via their C-terminal polyhistidine tails to nickel lipids integrated into the lipid bilayer. Despite favorable in vivo effects, concern remained over the potentially longer-term in vivo instability of noncovalent linkage of the trimers to the liposomes. Accordingly, we tested both cobalt coupling and covalent linkage of the trimers to the liposomes by reengineering the polyhistidine tail to include a free cysteine on each protomer of model BG505 NFL trimers to allow covalent linkage. Both cobalt and cysteine coupling resulted in a high-density array of NFL trimers that was stable in both 20% mouse serum and 100 mM EDTA, whereas the nickel-conjugated trimers were not stable under these conditions. Binding analysis and calcium flux with anti-Env-specific B cells confirmed that the trimers maintained conformational integrity following coupling. Following immunization of mice, serologic analysis demonstrated that the covalently coupled trimers elicited Env-directed antibodies in a manner statistically significantly improved compared to soluble trimers and nickel-conjugated trimers. Importantly, the covalent coupling not only enhanced gp120-directed responses compared to soluble trimers, it also completely eliminated antibodies directed to the C-terminal His tag located at the “bottom” of the spike. In contrast, soluble and noncovalent formats efficiently elicited anti-His tag antibodies. These data indicate that covalent linkage of well-ordered trimers to liposomes in high-density array displays multiple advantages in vitro and in vivo. IMPORTANCE Enveloped viruses typically encode a surface-bound glycoprotein that mediates viral entry into host cells and is a primary target for vaccine design. Liposomes with modified lipid head groups have a unique feature of capturing and displaying antigens on their surfaces, mimicking the native pathogens. Our first-generation nickel-based liposomes captured HIV-1 Env glycoprotein trimers via a noncovalent linkage with improved efficacy over soluble glycoprotein in activating germinal center B cells and eliciting tier-2 autologous neutralizing antibodies. In this study, we report the development of second-generation cobalt- and maleimide-based liposomes that have improved in vitro stability over nickel-based liposomes. In particular, the maleimide liposomes captured HIV-1 Env trimers via a more stable covalent bond, resulting in enhanced germinal center B cell responses that generated higher antibody titers than the soluble trimers and liposome-bearing trimers via noncovalent linkages. We further demonstrate that covalent coupling prevents release of the trimers prior to recognition by B cells and masks a nonneutralizing determinant located at the bottom of the trimer.

scholarly journals Autoreactive marginal zone B cells are spontaneously activated but lymph node B cells require T cell help

2006 ◽  
Vol 203 (8) ◽  
pp. 1985-1998 ◽  
Author(s):  
Laura Mandik-Nayak ◽  
Jennifer Racz ◽  
Barry P. Sleckman ◽  
Paul M. Allen
Keyword(s):  
Lymph Node ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Marginal Zone ◽  
B Cell Tolerance ◽  
Marginal Zone B Cells ◽  
T Cell Help

In K/BxN mice, arthritis is induced by autoantibodies against glucose-6-phosphate-isomerase (GPI). To investigate B cell tolerance to GPI in nonautoimmune mice, we increased the GPI-reactive B cell frequency using a low affinity anti-GPI H chain transgene. Surprisingly, anti-GPI B cells were not tolerant to this ubiquitously expressed and circulating autoantigen. Instead, they were found in two functionally distinct compartments: an activated population in the splenic marginal zone (MZ) and an antigenically ignorant one in the recirculating follicular/lymph node (LN) pool. This difference in activation was due to increased autoantigen availability in the MZ. Importantly, the LN anti-GPI B cells remained functionally competent and could be induced to secrete autoantibodies in response to cognate T cell help in vitro and in vivo. Therefore, our study of low affinity autoreactive B cells reveals two distinct but potentially concurrent mechanisms for their activation, of which one is T cell dependent and the other is T cell independent.

scholarly journals IgM and IgD B cell receptors differentially respond to endogenous antigens and control B cell fate

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Mark Noviski ◽  
James L Mueller ◽  
Anne Satterthwaite ◽  
Lee Ann Garrett-Sinha ◽  
Frank Brombacher ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Fate ◽  
Plasma Cells ◽  
Autoreactive B Cells ◽  
Binding Domains ◽  
Bcr Signaling ◽  
And Control

Naive B cells co-express two BCR isotypes, IgM and IgD, with identical antigen-binding domains but distinct constant regions. IgM but not IgD is downregulated on autoreactive B cells. Because these isotypes are presumed to be redundant, it is unknown how this could impose tolerance. We introduced the Nur77-eGFP reporter of BCR signaling into mice that express each BCR isotype alone. Despite signaling strongly in vitro, IgD is less sensitive than IgM to endogenous antigen in vivo and developmental fate decisions are skewed accordingly. IgD-only Lyn−/− B cells cannot generate autoantibodies and short-lived plasma cells (SLPCs) in vivo, a fate thought to be driven by intense BCR signaling induced by endogenous antigens. Similarly, IgD-only B cells generate normal germinal center, but impaired IgG1+ SLPC responses to T-dependent immunization. We propose a role for IgD in maintaining the quiescence of autoreactive B cells and restricting their differentiation into autoantibody secreting cells.

scholarly journals Epstein-Barr Virus LMP2A Enhances B-Cell Responses In Vivo and In Vitro

2006 ◽  
Vol 80 (14) ◽  
pp. 6764-6770 ◽  
Author(s):  
Michelle Swanson-Mungerson ◽  
Rebecca Bultema ◽  
Richard Longnecker
Keyword(s):  
B Cells ◽  
B Cell ◽  
Epstein Barr Virus ◽  
Plasma Cells ◽  
Barr Virus ◽  
Epstein Barr ◽  
Hen Egg ◽  
Hen Egg Lysozyme

ABSTRACT Epstein-Barr virus (EBV) establishes latent infections in a significant percentage of the population. Latent membrane protein 2A (LMP2A) is an EBV protein expressed during latency that inhibits B-cell receptor signaling in lymphoblastoid cell lines. In the present study, we have utilized a transgenic mouse system in which LMP2A is expressed in B cells that are specific for hen egg lysozyme (E/HEL-Tg). To determine if LMP2A allows B cells to respond to antigen, E/HEL-Tg mice were immunized with hen egg lysozyme. E/HEL-Tg mice produced antibody in response to antigen, indicating that LMP2A allows B cells to respond to antigen. In addition, E/HEL-Tg mice produced more antibody and an increased percentage of plasma cells after immunization compared to HEL-Tg littermates, suggesting that LMP2A increased the antibody response in vivo. Finally, in vitro studies determined that LMP2A acts directly on the B cell to increase antibody production by augmenting the expansion and survival of the activated B cells, as well as increasing the percentage of plasma cells generated. Taken together, these data suggest that LMP2A enhances, not diminishes, B-cell-specific antibody responses in vivo and in vitro in the E/HEL-Tg system.

scholarly journals Telomerase activation in normal B lymphocytes and non-Hodgkin's lymphomas

Blood ◽  
1996 ◽  
Vol 88 (1) ◽  
pp. 222-229 ◽  
Author(s):  
KF Norrback ◽  
K Dahlenborg ◽  
R Carlsson ◽  
G Roos
Keyword(s):  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Telomerase Activity ◽  
Lymphoid Tissues ◽  
Low Grade ◽  
Malignant Lymphomas ◽  
Hodgkin's Lymphomas ◽  
Germinal Center B Cells

Activation of telomerase seems to be a prerequisite for immortalization and is found in permanent cell lines and most malignant tumors. Normal somatic cells are generally telomerase negative, except for bone marrow stem cells. Weak activity is also present in peripheral blood cells. In the present study strong telomerase activity was demonstrated in vivo in normal mature cells of the immune system, as well as in malignant lymphomas. Benign lymph nodes had lower telomerase activity than benign tonsils, which exhibited intermediate to high activity comparable with findings in malignant lymphomas. In benign tonsils the activity seemed to be restricted to germinal center B cells. In benign lymphoid tissues telomerase activity correlated with B-cell numbers and cell proliferation, but this was not observed in the lymphoma group. High- grade lymphomas exhibited higher levels of telomerase compared with low- grade cases. The data showed that in vivo activation of telomerase is a characteristic feature of germinal center B cells. Different signals for activation of telomerase are likely to exist, one of them being immune stimulation. The data suggest that telomerase activity in malignant lymphomas can be explained by an “induction and retention” model, ie, transformation occurs in a normal, mature B cell with reactivated telomerase, which is retained in the neoplastic clone.

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