scholarly journals G-CSF–stimulated Neutrophils Are a Prominent Source of Functional BLyS

2003 ◽  
Vol 197 (3) ◽  
pp. 297-302 ◽  
Author(s):  
Patrizia Scapini ◽  
Bernardetta Nardelli ◽  
Gianpaolo Nadali ◽  
Federica Calzetti ◽  
Giovanni Pizzolo ◽  
...  
Keyword(s):  
B Cell ◽  
B Lymphocyte ◽  
Serum Levels ◽  
Surface Expression ◽  
Biologically Active ◽  
Human Neutrophils ◽  
Activated Neutrophils ◽  
B Cell Homeostasis

B lymphocyte stimulator (BLyS) is a novel member of the TNF ligand superfamily that is important in B cell maturation and survival. We demonstrate that human neutrophils, after incubation with G-CSF or, less efficiently, IFNγ, express high levels of BLyS mRNA and release elevated amounts of biologically active BLyS. In contrast, surface expression of the membrane-bound BLyS was not detected in activated neutrophils. Indeed, in neutrophils, uniquely among other myeloid cells, soluble BLyS is processed intracellularly by a furin-type convertase. Worthy of note, the absolute capacity of G-CSF–stimulated neutrophils to release BLyS was similar to that of activated monocytes or dendritic cells, suggesting that neutrophils might represent an important source of BLyS. In this regard, we show that BLyS serum levels as well as neutrophil-associated BLyS are significantly enhanced after in vivo administration of G-CSF in patients. In addition, serum obtained from two of these patients induced a remarkable accumulation of neutrophil-associated BLyS in vitro. This effect was neutralized by anti–G-CSF antibodies, indicating that G-CSF, present in the serum, stimulated neutrophils to produce BLyS. Collectively, our findings suggest that neutrophils, through the production of BLyS, might play an unsuspected role in the regulation of B cell homeostasis.

Fetal liver pro-B and pre-B lymphocyte clones: expression of lymphoid-specific genes, surface markers, growth requirements, colonization of the bone marrow, and generation of B lymphocytes in vivo and in vitro

1992 ◽  
Vol 12 (2) ◽  
pp. 518-530
Author(s):  
R Palacios ◽  
J Samaridis
Keyword(s):  
B Cell ◽  
B Lymphocytes ◽  
Stromal Cells ◽  
B Lymphocyte ◽  
Germ Line ◽  
Fetal Liver ◽  
Rag 1 ◽  
B Cell Precursors

We describe here the development and characterization of the FLS4.1 stromal line derived from 15-day fetal liver of BALB/c embryos and defined culture conditions that efficiently support the cloning and long-term growth of nontransformed B-220+ 14-day fetal liver cells at two stages of B-cell development, namely, pro-B lymphocytes (immunoglobulin [Ig] genes in germ line configuration) and pre-B cells (JH-rearranged genes with both light-chain Ig genes in the germ line state). All B-cell precursor clones require recombinant interleukin-7 (rIL-7) and FLS4.1 stromal cells for continuous growth in culture, but pro-B lymphocyte clones can also proliferate in rIL-3. None proliferate in rIL-1, rIL-2, rIL-4, rIL-5, rIL-6, or leukemia inhibitory factor. FLS4.1 stromal cells synthesize mRNA for Steel factor but not for IL-1 to IL-7; all pro-B and pre-B clones express c-Kit, the receptor for Steel factor, and a c-Kit-specific antibody inhibits the enhanced proliferative response of fetal liver B-220+ B-cell precursors supported by FLS4.1 stromal cells and exogenous rIL-7 but does not affect that promoted by rIL-7 alone. Northern (RNA) blot analysis of the expression of the MB-1, lambda 5, Vpre-B, c mu, RAG-1, and RAG-2 genes in pro-B and pre-B clones show that transcription of the MB-1 gene precedes IgH gene rearrangement and RNA synthesis from c mu, RAG-1, RAG-2, lambda 5, and Vpre-B genes. All clones at the pre-B-cell stage synthesize mRNA for c mu, RAG-1, and RAG-2 genes; transcription of the lambda 5 and Vpre-B genes seems to start after D-to-JH rearrangement in B-cell precursors, indicating that the proteins encoded by either gene are not required for B-cell progenitors to undergo D-to-JH gene rearrangement. These findings mark transcription of the MB-1 gene as one of the earliest molecular events in commitment to develop along the B-lymphocyte pathway. Indeed, both pro-B and pre-B clones can generate in vitro and in vivo B lymphocytes but not T lymphocytes; moreover, these clones do not express the CD3-gamma T-cell-specific gene, nor do they have rearranged gamma, delta, or beta T-cell antigen receptor genes.

scholarly journals TACI-BLyS signaling via B-cell–dendritic cell cooperation is required for naive CD8+ T-cell priming in vivo

Blood ◽  
2006 ◽  
Vol 107 (2) ◽  
pp. 594-601 ◽  
Author(s):  
Yaiza Diaz-de-Durana ◽  
George T. Mantchev ◽  
Richard J. Bram ◽  
Alessandra Franco
Keyword(s):  
B Cells ◽  
Dendritic Cell ◽  
B Cell ◽  
B Lymphocyte ◽  
Costimulatory Molecule ◽  
Early Signal ◽  
Maturation In Vitro ◽  
Deficient Mice

AbstractWe demonstrated that B-cell–dendritic cell (DC) interactions via transmembrane activator and calcium modulator and cyclophilin ligand (CAML) interactor (TACI) and B-lymphocyte stimulator (BLyS) provide an early signal critical to generate adequate numbers of mature antigen presenting cells (APCs) to prime naive CD8+ T cells (CTLs) in vivo. Evidence that B cells are required for efficient CTL generation in mice and that reconstitution with wild-type but not TACI-knockout B cells restored normal CTL responses support our conclusion. Moreover, low doses of a TACI fusion protein (TACI-Fc) that express the extracellular domain of TACI (amino acid [aa] 1-126) restored CTL priming in B-cell–deficient mice in vivo and induced DC maturation in vitro. In fact, following interactions with B cells, splenic DCs rapidly express the CD86 costimulatory molecule, to an extent comparable to the exposure to antigenic stimuli. BLyShigh peptide-pulsed bone marrow–derived DCs, used as vaccines in vivo, cannot generate CTLs in B-cell–deficient and TACI-deficient mice, strongly supporting a need for B-cell–DC cooperation through TACI-BLyS during CTL first encounter with antigens in vivo.

scholarly journals Loss of the Pro-Apoptotic BH3-only Bcl-2 Family Member Bim Inhibits BCR Stimulation–induced Apoptosis and Deletion of Autoreactive B Cells

2003 ◽  
Vol 198 (7) ◽  
pp. 1119-1126 ◽  
Author(s):  
Anselm Enders ◽  
Philippe Bouillet ◽  
Hamsa Puthalakath ◽  
Yuekang Xu ◽  
David M. Tarlinton ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Family Member ◽  
B Lymphocyte ◽  
Survival Function ◽  
Autoreactive B Cells ◽  
Induced Apoptosis ◽  
Self Antigen

During development, the stochastic process assembling the genes encoding antigen receptors invariably generates B and T lymphocytes that can recognize self-antigens. Several mechanisms have evolved to prevent the activation of these cells and the concomitant development of autoimmune disease. One such mechanism is the induction of apoptosis in developing or mature B cells by engagement of the B cell antigen receptor (BCR) in the absence of T cell help. Here we report that B lymphocytes lacking the pro-apoptotic Bcl-2 family member Bim are refractory to apoptosis induced by BCR ligation in vitro. The loss of Bim also inhibited deletion of autoreactive B cells in vivo in two transgenic systems of B cell tolerance. Bim loss prevented deletion of autoreactive B cells induced by soluble self-antigen and promoted accumulation of self-reactive B cells developing in the presence of membrane-bound self-antigen, although their numbers were considerably lower compared with antigen-free mice. Mechanistically, we determined that BCR ligation promoted interaction of Bim with Bcl-2, inhibiting its survival function. These findings demonstrate that Bim is a critical player in BCR-mediated apoptosis and in B lymphocyte deletion.

scholarly journals Granulocytic Myeloid-Derived Suppressor Cell Exosomal Prostaglandin E2 Ameliorates Collagen-Induced Arthritis by Enhancing IL-10+ B Cells

2020 ◽  
Vol 11 ◽  
Author(s):  
Xinyu Wu ◽  
Dongwei Zhu ◽  
Jie Tian ◽  
Xinyi Tang ◽  
Hongye Guo ◽  
...  
Keyword(s):  
B Cells ◽  
Prostaglandin E2 ◽  
Plasma Cells ◽  
Suppressor Cells ◽  
Suppressor Cell ◽  
Serum Levels ◽  
Biologically Active ◽  
Collagen Induced Arthritis

The results of recent studies have shown that granulocytic-myeloid derived suppressor cells (G-MDSCs) can secrete exosomes that transport various biologically active molecules with regulatory effects on immune cells. However, their roles in autoimmune diseases such as rheumatoid arthritis remain to be further elucidated. In the present study, we investigated the influence of exosomes from G-MDSCs on the humoral immune response in murine collagen-induced arthritis (CIA). G-MDSCs exosomes-treated mice showed lower arthritis index values and decreased inflammatory cell infiltration. Treatment with G-MDSCs exosomes promoted splenic B cells to secrete IL-10 both in vivo and in vitro. In addition, a decrease in the proportion of plasma cells and follicular helper T cells was observed in drainage lymph nodes from G-MDSCs exosomes-treated mice. Moreover, lower serum levels of IgG were detected in G-MDSCs exosomes-treated mice, indicating an alteration of the humoral environment. Mechanistic studies showed that exosomal prostaglandin E2 (PGE2) produced by G-MDSCs upregulated the phosphorylation levels of GSK-3β and CREB, which play a key role in the production of IL-10+ B cells. Taken together, our findings demonstrated that G-MDSC exosomal PGE2 attenuates CIA in mice by promoting the generation of IL-10+ Breg cells.

scholarly journals Stimulation of neutrophil oxidative metabolism by the alternate pathway of complement activation: a mechanism for the spontaneous NBT test

Blood ◽  
1975 ◽  
Vol 45 (6) ◽  
pp. 843-849 ◽  
Author(s):  
RG Strauss ◽  
AM Mauer ◽  
T Asbrock ◽  
RE Spitzer ◽  
AE Stitzel
Keyword(s):  
Complement Activation ◽  
Oxidative Metabolism ◽  
Alternative Pathway ◽  
Metabolic Activation ◽  
Biologically Active ◽  
Nitroblue Tetrazolium ◽  
Human Neutrophils ◽  
Alternate Pathway

Abstract The reduction of nitroblue tetrazolium dye by human neutrophils was measured in the presence of serum in which the complement system had been activated through the alternate pathway by interaction with inulin. Neutrophils incubated with serum inulin supernatants reduced the dye and showed a general increase in oxidative metabolism. The oxidation of glucose-1–14-C by supernatant prepared from selectively depleted sera indicated that the neutrophil-stimulating factor(s) was generated through the alternate pathway of complement activation. The possibility that inulun had been ingested as a particle was ruled out by light microscopy and radiolabeling studies. The failure of neutrophils stimulated by the serum-inulun supernatants to migrate after exposure to a chemotactic agent suggested that the site of neutrophil-complement interaction was on the cell membrane. It is concluded from these results that biologically active fragments generated through the alternative pathway of complement activation can stimulate neutrophil metabolism in the absence of phagocytosis. Interaction of such fragments with circulating neutrophils in vivo and the subsequent metabolic activation of these cells is one explanation for the spontaneous reduction of nitroblue tetrazolium dye in vitro by neutrophils from patients with certain infections and inflammatory disorders.

CAP-100: First-in-class antibody for CCR7+ hematological malignancies.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e19008-e19008
Author(s):  
Carlos Cuesta ◽  
Cecilia Munoz-Callega ◽  
Javier Loscertales ◽  
Fernando Terron ◽  
Wim Mol
Keyword(s):  
T Cell ◽  
B Cell ◽  
Hematological Malignancies ◽  
Surface Expression ◽  
Cell Killing ◽  
Tumor Growth Inhibition ◽  
Killing Activity ◽  
T Lymphomas

e19008 Background: CCR7 is highly expressed in many hematological malignancies including CLL, several B-cell non-Hodgkin lymphomas (NHL), and various T-cell neoplasias with nodal involvement. Upon engagement by its ligands (CCL19 and CCL21), CCR7 controls trafficking of cells to locations where these chemokines are expressed, such as the lymph node (LN) and central nervous system. In these protective microenvironments CCR7 ligands contribute to tumor cell survival and proliferation. Indeed, both high CCR7 surface expression levels and high migratory responses to CCR7 ligands correlate with LN involvement, adverse prognostic factors, and shorter patient survival. Thus, strategies targeting CCR7 could provide a novel therapeutic approach for CCR7+ hematological malignancies. Methods: We have generated CAP-100, the first humanized immunoglobulin G1 (IgG1) monoclonal antibody (mAb) that specifically binds to human CCR7 and neutralizes ligand-mediated signaling from both CCL19 and CCL21, and evaluated the antibody in various in-vitro and in-vivo preclinical models. Results: CAP-100 effectively inhibited in vitro migration of primary patient samples of CLL, B-cell NHLs and T-cell neoplasias such as T-PLL or T-ALL. Furthermore, in in vivo pre-clinical studies, CAP-100 was shown to inhibit entry of CCR7-expressing cells to LNs. CAP-100 also abrogated survival elicited by CCR7 in CLL, and showed potent cell killing activity against CLL or CCR7+ T-lymphomas cells. This Fc-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) clearly outperformed anti-CD20 or anti-CD52 standard-of-care antibodies in B-NHL and T-lymphomas respectively. In all cases, ADCC and migration inhibition were both independent of prognostic markers for high risk disease. Finally, when given as monotherapy in disseminated B-NHL and CLL xenograft tumors in SCID mice, CAP-100 exhibited tumor growth inhibition and extended survival significantly. Conclusions: Our results demonstrate that CAP-100, the first-in-class anti-CCR7 mAb, is a potent antagonist with biological activity in several CCR7+ hematological malignancies, including relapsed/refractory disease. Moreover, these results highlight the relevance of the CCR7-CCL19/CCL21 pathway as a therapeutic target in these diseases. CAP-100’s unique propensity to block migration of tumor cells to the LN, in combination with its potent cell killing activity provides the biological rationale for use of CAP-100, either as monotherapy or in combination with novel agents. Clinical trials in CLL and CCR7-expressing NHL will be initiated soon.

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

2002 ◽  
Vol 22 (13) ◽  
pp. 4771-4780 ◽  
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.

scholarly journals B lymphocytes undergo TLR2-dependent apoptosis upon Shigella infection

2014 ◽  
Vol 211 (6) ◽  
pp. 1215-1229 ◽  
Author(s):  
Katharina Nothelfer ◽  
Ellen T. Arena ◽  
Laurie Pinaud ◽  
Michel Neunlist ◽  
Brian Mozeleski ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cell ◽  
B Lymphocytes ◽  
B Lymphocyte ◽  
Ex Vivo ◽  
Functionally Impaired ◽  
Rectal Biopsies ◽  
Type Three Secretion

Antibody-mediated immunity to Shigella, the causative agent of bacillary dysentery, requires several episodes of infection to get primed and is short-lasting, suggesting that the B cell response is functionally impaired. We show that upon ex vivo infection of human colonic tissue, invasive S. flexneri interacts with and occasionally invades B lymphocytes. The induction of a type three secretion apparatus (T3SA)–dependent B cell death is observed in the human CL-01 B cell line in vitro, as well as in mouse B lymphocytes in vivo. In addition to cell death occurring in Shigella-invaded CL-01 B lymphocytes, we provide evidence that the T3SA needle tip protein IpaD can induce cell death in noninvaded cells. IpaD binds to and induces B cell apoptosis via TLR2, a signaling receptor thus far considered to result in activation of B lymphocytes. The presence of bacterial co-signals is required to sensitize B cells to apoptosis and to up-regulate tlr2, thus enhancing IpaD binding. Apoptotic B lymphocytes in contact with Shigella-IpaD are detected in rectal biopsies of infected individuals. This study therefore adds direct B lymphocyte targeting to the diversity of mechanisms used by Shigella to dampen the host immune response.

TEL-AML1 promotes development of specific hematopoietic lineages consistent with preleukemic activity

Blood ◽  
2004 ◽  
Vol 103 (10) ◽  
pp. 3890-3896 ◽  
Author(s):  
Michelle Morrow ◽  
Sarah Horton ◽  
Dimitris Kioussis ◽  
Hugh J. M. Brady ◽  
Owen Williams
Keyword(s):  
B Cell ◽  
B Lymphocyte ◽  
Specific Activity ◽  
Fetal Liver ◽  
Cell Lineage ◽  
Retroviral Vectors ◽  
Fusion Product ◽  
Pediatric Leukemia

Abstract The t(12;21)(p13;q22) translocation is the most common chromosomal abnormality yet identified in any pediatric leukemia and gives rise to the TEL-AML1 fusion product. To investigate the effects of TEL-AML1 on hematopoiesis, fetal liver hematopoietic progenitor cells (HPCs) were transduced with retroviral vectors expressing this fusion protein. We show that TEL-AML1 dramatically alters differentiation of HPCs in vitro, preferentially promoting B-lymphocyte development, enhancing self-renewal of B-cell precursors, and leading to the establishment of long-term growth factor–dependent pre–B-cell lines. However, it had no effect on myeloid development in vitro. Further experiments were performed to determine whether TEL-AML1 also demonstrates lineage-specific activity in vivo. TEL-AML1–expressing HPCs displayed a competitive advantage in reconstituting both B-cell and myeloid lineages in vivo but had no effect on reconstitution of the T-cell lineage. Despite promoting these alterations in hematopoiesis, TEL-AML1 did not induce leukemia in transplanted mice. Our study provides a unique insight into the role of TEL-AML1 in leukemia predisposition and a potential model to study the mechanism of leukemogenesis associated with this fusion.

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