Sequential induction of NF-kappa B/Rel family proteins during B-cell terminal differentiation

The NF-kappa B/Rel family of at least five transcription factor polypeptides is thought to function both as a developmental regulator in B cells and as a rapid response system in all cells. To examine this notion in more detail, we determined the protein contents of both the inducible and constitutive NF-kappa B/Rel activities in a pre-B-cell line, 70Z/3, and a mature B-cell line, WEHI 231. NF-kappa B p50/p65 is the major inducible nuclear complex after lipopolysaccharide or phorbol myristate acetate treatment of 70Z/3 cells. The constitutive and inducible complexes in WEHI 231 cells are mainly composed of p50 and Rel. The constitutive or induced activities are all sensitive to I kappa B-alpha, but this inhibitor is very short-lived in WEHI 231 cells, suggesting that the balance between synthesis and degradation of I kappa B-alpha determines whether a particular cell lineage has constitutive activity. A patterned expression of the NF-kappa B/Rel activator proteins emerges from an analysis of other B-lineage cell lines and splenic B cells: mainly p50 and p65 in pre-B (and non-B) cells, a predominance of Rel and p50 in mature B cells, and expression of p52 and RelB in plasmacytoma lines. This ordered pattern of regulators may reflect the requirement for expression of different genes during terminal B-cell differentiation because different combinations of NF-kappa B/Rel family members preferentially activate distinct kappa B sites in reporter constructs.

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Apoptosis induced by the antigen receptor and Fas in a variant of the immature B cell line WEHI-231 and in splenic immature B cells

International Immunology ◽

10.1093/intimm/13.4.581 ◽

2001 ◽

Vol 13 (4) ◽

pp. 581-592 ◽

Cited By ~ 6

Author(s):

Maoxin Tim Tian ◽

Chih-Hao Gilbert Chou ◽

Anthony L. DeFranco

Keyword(s):

B Cells ◽

B Cell ◽

Cell Line ◽

Antigen Receptor ◽

Wehi 231 ◽

Immature B Cells

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The immunomodulatory functions and molecular mechanism of a new bursal heptapeptide (BP7) in immune responses and immature B cells

Veterinary Research ◽

10.1186/s13567-019-0682-7 ◽

2019 ◽

Vol 50 (1) ◽

Cited By ~ 1

Author(s):

Xiu Li Feng ◽

Yang Zheng ◽

Man Man Zong ◽

Shan Shan Hao ◽

Guang Fang Zhou ◽

...

Keyword(s):

B Cells ◽

Immune Responses ◽

B Cell ◽

Molecular Mechanisms ◽

Bursa Of Fabricius ◽

Biological Factor ◽

Mrna Levels ◽

B Cell Differentiation ◽

Immune Functions ◽

Wehi 231

Abstract The bursa of Fabricius (BF) is the acknowledged central humoural immune organ unique to birds and plays a vital role in B lymphocyte development. In addition, the unique molecular immune features of bursal-derived biological peptides involved in B cell development are rarely reported. In this paper, a novel bursal heptapeptide (BP7) with the sequence GGCDGAA was isolated from the BF and was shown to enhance the monoclonal antibody production of a hybridoma. A mouse immunization experiment showed that mice immunized with an AIV antigen and BP7 produced strong antibody responses and cell-mediated immune responses. Additionally, BP7 stimulated increased mRNA levels of sIgM in immature mouse WEHI-231 B cells. Gene microarray results confirmed that BP7 regulated 2465 differentially expressed genes in BP7-treated WEHI-231 cells and induced 13 signalling pathways and various immune-related functional processes. Furthermore, we found that BP7 stimulated WEHI-231 cell autophagy and AMPK-ULK1 phosphorylation and regulated Bcl-2 protein expression. Finally, chicken immunization showed that BP7 enhanced the potential antibody and cytokine responses to the AIV antigen. These results suggested that BP7 might be an active biological factor that functions as a potential immunopotentiator, which provided some novel insights into the molecular mechanisms of the effects of bursal peptides on immune functions and B cell differentiation.

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The BTB-ZF transcription factor Zbtb20 is driven by Irf4 to promote plasma cell differentiation and longevity

Journal of Experimental Medicine ◽

10.1084/jem.20131831 ◽

2014 ◽

Vol 211 (5) ◽

pp. 827-840 ◽

Cited By ~ 52

Author(s):

Stéphane Chevrier ◽

Dianne Emslie ◽

Wei Shi ◽

Tobias Kratina ◽

Cameron Wellard ◽

...

Keyword(s):

Cell Differentiation ◽

B Cells ◽

B Cell ◽

Plasma Cell ◽

Cell Cycle Progression ◽

Plasma Cells ◽

Cell Lineage ◽

B Cell Differentiation ◽

Antibody Secreting Cell ◽

Important Player

The transcriptional network regulating antibody-secreting cell (ASC) differentiation has been extensively studied, but our current understanding is limited. The mechanisms of action of known “master” regulators are still unclear, while the participation of new factors is being revealed. Here, we identify Zbtb20, a Bcl6 homologue, as a novel regulator of late B cell development. Within the B cell lineage, Zbtb20 is specifically expressed in B1 and germinal center B cells and peaks in long-lived bone marrow (BM) ASCs. Unlike Bcl6, an inhibitor of ASC differentiation, ectopic Zbtb20 expression in primary B cells facilitates terminal B cell differentiation to ASCs. In plasma cell lines, Zbtb20 induces cell survival and blocks cell cycle progression. Immunized Zbtb20-deficient mice exhibit curtailed humoral responses and accelerated loss of antigen-specific plasma cells, specifically from the BM pool. Strikingly, Zbtb20 induction does not require Blimp1 but depends directly on Irf4, acting at a newly identified Zbtb20 promoter in ASCs. These results identify Zbtb20 as an important player in late B cell differentiation and provide new insights into this complex process.

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Deletion of genes encoding PU.1 and Spi-B in B cells impairs differentiation and induces pre-B cell acute lymphoblastic leukemia

Blood ◽

10.1182/blood-2011-02-335539 ◽

2011 ◽

Vol 118 (10) ◽

pp. 2801-2808 ◽

Cited By ~ 30

Author(s):

Kristen M. Sokalski ◽

Stephen K. H. Li ◽

Ian Welch ◽

Heather-Anne T. Cadieux-Pitre ◽

Marek R. Gruca ◽

...

Keyword(s):

Transcription Factor ◽

Cell Differentiation ◽

Acute Lymphoblastic Leukemia ◽

B Cells ◽

B Cell ◽

Lymphoblastic Leukemia ◽

Cell Lineage ◽

B Cell Differentiation ◽

Cell Acute Lymphoblastic Leukemia ◽

Ets Transcription Factor

Abstract The E26 transformation-specific (Ets) transcription factor PU.1 is required to generate lymphoid progenitor cells from hematopoietic stem cells, but it is not required to generate B cells from committed B-cell lineage progenitors. We hypothesized that PU.1 function in B-cell differentiation is complemented by the related Ets transcription factor Spi-B. To test this hypothesis, mice were generated lacking both PU.1 and Spi-B in the B-cell lineage. Unlike mice lacking PU.1 or Spi-B, mice deficient in both PU.1 and Spi-B in the B-cell lineage had reduced frequencies of B cells as well as impaired B-cell differentiation. Strikingly, all PU.1 and Spi-B–deficient mice developed pre-B cell acute lymphoblastic leukemia before 30 weeks of age. Pre-B cells accumulated in the thymus resulting in massive thymic enlargement and dyspnea. These findings demonstrate that PU.1 and Spi-B are essential transcriptional regulators of B-cell differentiation as well as novel tumor suppressors in the B-cell lineage.

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Regulation of the pro-B-cell-specific enhancer of the Id1 gene involves the C/EBP family of proteins.

Molecular and Cellular Biology ◽

10.1128/mcb.17.2.844 ◽

1997 ◽

Vol 17 (2) ◽

pp. 844-850 ◽

Cited By ~ 25

Author(s):

S Saisanit ◽

X H Sun

Keyword(s):

B Cells ◽

B Cell ◽

Negative Regulator ◽

Transcriptional Level ◽

B Cell Differentiation ◽

Mobility Shift ◽

Specific Expression ◽

Enhancer Activity ◽

Wehi 231

The Id1 protein acts as a negative regulator in early-B-cell differentiation by antagonizing the function of the basic helix-loop-helix transcription factors. Expression of the Id1 gene during B-cell development is governed at the transcriptional level primarily by a pro-B-cell-specific enhancer (PBE) located 3 kb downstream of the gene. We report here the identification of CAAT/enhancer binding protein beta (C/EBPbeta) as a component of the two major PBE-binding complexes (PBEC1 and PBEC2) found in pro-B cells by gel mobility shift assays. Formation of the PBECs is abolished when a classic C/EBP binding site is used as a competitor, and binding complexes similar to the PBECs are formed when the classic C/EBP site is used as a probe. We show that CHOP, a negative regulator of C/EBPs, specifically inhibits PBE binding in vitro and its enhancer activity in vivo. In pro-B cells, C/EBPbeta binds to the PBE site not as apparent homodimers but possibly in association with at least one other polypeptide, which might determine the pro-B-cell-specific expression of the Id1 gene. Although isoforms of C/EBPbeta are expressed in various B cells, they bind to DNA only in LyD9 and Ba/F3 pro-B cells. We show that CHOP is expressed in 70Z/3 and WEHI-231 cells. We also demonstrate that CHOP is associated with C/EBPbeta in WEHI-231 cells, which may provide an additional mechanism to control the function of C/EBPbeta and the expression of the Id1 gene.

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Immunologic heterogeneity of diffuse large cell lymphoma

Blood ◽

10.1182/blood.v65.3.630.bloodjournal653630 ◽

1985 ◽

Vol 65 (3) ◽

pp. 630-637

Author(s):

AS Freedman ◽

AW Boyd ◽

KC Anderson ◽

DC Fisher ◽

GS Pinkus ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

B Lymphocytes ◽

Cell Lymphoma ◽

Cell Lineage ◽

Large Cell ◽

B Cell Differentiation ◽

Diffuse Large Cell Lymphoma ◽

Normal Spleen ◽

Large Cell Lymphoma

The cellular lineage of 57 diffuse large-cell lymphomas (DLCLs) was determined using a panel of monoclonal antibodies directed against lineage-restricted and -associated T, B, and monocyte antigens. The majority (82%) were of B cell lineage as determined by the expression of sig and/or B1, with the remaining 16% being of T cell lineage and 2%, of monocyte-myeloid lineage. By the expression of other B cell- restricted and -associated antigens, two major and two minor subgroups could be identified. These subgroups expressed the following phenotypes: (1) B1+B4+sIG+B2- (51%); (2) B1+B4+sIg+B2+ (29%); (3) B1+B4+sIg-B2+ (10%); and (4) B1+B4-sIg+B2- (10)%. The morphology of transformed lymphocytes, the weak to absent expression of the early B cell antigens B2 and sIgD, and the absence of the late B cell differentiation antigens PCA-1 and PC-1 suggested that these tumors were the neoplastic counterparts of normal B cells at the mid-stages of differentiation. Further support for the notion that B-DLCLs correspond to transformed B lymphocytes was concluded from the observation that B cells could be identified in normal spleen that expressed the cell surface phenotype and morphological appearance of the majority of B- DLCLs.

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RasGRP1 Sensitizes an Immature B Cell Line to Antigen Receptor-induced Apoptosis

Journal of Biological Chemistry ◽

10.1074/jbc.m314273200 ◽

2004 ◽

Vol 279 (19) ◽

pp. 19523-19530 ◽

Cited By ~ 23

Author(s):

Benoit Guilbault ◽

Robert J. Kay

Keyword(s):

T Cells ◽

B Cells ◽

B Cell ◽

Cell Line ◽

Cell Receptor ◽

B Cell Receptor ◽

Dominant Negative ◽

Dominant Negative Mutant ◽

Wehi 231 ◽

Induced Apoptosis

RasGRP1 is a guanine nucleotide exchange factor that activates Ras GTPases and is activated downstream of antigen receptors on both T and B lymphocytes. Ras-GRP1 provides signals to immature T cells that confer survival and proliferation, but RasGRP1 also promotes T cell receptor-mediated deletion of mature T cells. We used the WEHI-231 cell line as an experimental system to determine whether RasGRP1 can serve as a quantitative modifier of B cell receptor-induced deletion of immature B cells. A 2-fold elevation in RasGRP1 expression markedly increased apoptosis of WEHI-231 cells following B cell receptor ligation, whereas a dominant negative mutant of RasGRP1 suppressed B cell receptor-induced apoptosis. Activation of ERK1 or ERK2 kinases was not required for RasGRP1-mediated apoptosis. Instead, elevated RasGRP1 expression caused down-regulation of NF-κB and Bcl-xL, which provide survival signals counter-acting apoptosis induction by B cell receptor. Inhibition of NF-κB was sufficient to enhance B cell receptor-induced apoptosis of WEHI-231 cells, and ligation of co-stimulatory receptors that activate NF-κB suppressed the ability of RasGRP1 to promote B cell receptor-induced apoptosis. These experiments define a novel apoptosis-promoting pathway leading from B cell receptor to the inhibition of NF-κB and demonstrate that differential expression of RasGRP1 has the potential to modulate the sensitivities of B cells to negative selection following antigen encounter.

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B-1 Cell Development: Evidence for an Uncommitted Immunoglobulin (Ig)M+ B Cell Precursor in B-1 Cell Differentiation

Journal of Experimental Medicine ◽

10.1084/jem.187.8.1325 ◽

1998 ◽

Vol 187 (8) ◽

pp. 1325-1334 ◽

Cited By ~ 64

Author(s):

Stephen H. Clarke ◽

Larry W. Arnold

Keyword(s):

Cell Differentiation ◽

B Cells ◽

B Cell ◽

Cell Lineage ◽

Signal Transduction Pathway ◽

Cell Receptor ◽

Cell Development ◽

Immunoglobulin Gene ◽

B Cell Differentiation ◽

Receptor Signal

Murine phosphatidyl choline (PtC)–specific B cells in normal mice belong exclusively to the B-1 subset. Analysis of anti-PtC (VH12 and VH12/Vκ4) transgenic (Tg) mice indicates that exclusion from B-0 (also known as B-2) occurs after immunoglobulin gene rearrangement. This predicts that PtC-specific B-0 cells are generated, but subsequently eliminated by either apoptosis or differentiation to B-1. To investigate the mechanism of exclusion, PtC-specific B cell differentiation was examined in mice expressing the X-linked immunodeficiency (xid) mutation. xid mice lack functional Bruton's tyrosine kinase (Btk), a component of the B cell receptor signal transduction pathway, and are deficient in B-1 cell development. We find in C57BL/ 6.xid mice that VH12 pre-BII cell selection is normal and that PtC-specific B cells undergo modest clonal expansion. However, the majority of splenic PtC-specific B cells in anti-PtC Tg/xid mice are B-0, rather than B-1 as in their non-xid counterparts. These data indicate that PtC-specific B-0 cell generation precedes segregation as predicted, and that Btk function is required for efficient segregation to B-1. Since xid mice exhibit defective B cell differentiation, not programmed cell death, these data are most consistent with an inability of PtC-specific B-0 cells to convert to B-1 and a single B cell lineage.

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G protein subunit G alpha 16 expression is restricted to progenitor B cells during human B-cell differentiation

Blood ◽

10.1182/blood.v85.7.1836.bloodjournal8571836 ◽

1995 ◽

Vol 85 (7) ◽

pp. 1836-1842 ◽

Cited By ~ 21

Author(s):

MY Mapara ◽

K Bommert ◽

RC Bargou ◽

C Leng ◽

C Beck ◽

...

Keyword(s):

Cell Differentiation ◽

B Cells ◽

B Cell ◽

Cell Line ◽

Cell Lines ◽

B Cell Lymphoma ◽

Cell Phenotype ◽

Low Grade ◽

B Cell Differentiation ◽

Human B Cell

Recently G alpha 16, a new guanosine triphosphate (GTP) binding protein alpha subunit has been described to be specifically expressed in human hematopoietic cells. Expression of G alpha 16 was observed in human cell lines of myelomonocytic and T-lymphocytic origin, but not in human B-cell lines Raji and IM9. We studied the expression of G alpha 16 in human B cells corresponding to different stages of B-cell differentiation by means of reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. The human Burkitt's lymphoma cell lines Raji, Ramos, BJAB, the lymphoblastoid cell line SKW6.4, and the plasmocytoma cell line U266 were devoid of G alpha 16. In contrast, G alpha 16 was detected in the human progenitor B cell lines Reh and Nalm-6. Using the mu+, k-cell line BLIN-1 (pre-B cell phenotype) and its derived subclone 1E8 (surface mu+, k+; B-cell phenotype) G alpha 16 expression was found to disappear on transition from pre-B to B-cell differentiation stage. The analysis of a broad panel of human neoplastic B lymphocytes ranging from progenitor B-acute lymphatic leukemia (pre-pre-B-ALL), common acute leukemias (cALL), pre-B-ALL, mature B-ALL to low grade B-cell lymphoma (chronic lymphocytic leukemia of B-cell type, leukemic centrocytic non-Hodgkins lymphoma [NHL], hairy cell leukemia) showed that G alpha 16 expression is limited to progenitor and pre-B-ALL cells. Therefore, we conclude that within B-cell differentiation, G alpha 16 is expressed solely during early B cell ontogeny and downregulated during differentiation. Thus, G alpha 16 might be an important regulator involved in signaling processes in progenitor B cells.

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