Activation of channel catfish B cells by membrane immunoglobulin cross-linking

In vivo experiments were performed to determine whether the cross-linking of membrane immunoglobulin (mIg) D on mature B cells, in the absence of T cell help, leads to B cell death. Mice were injected with either a monoclonal antibody (mAb) that cross-links mIgD effectively or a mAb that binds to mIgD avidly but cross-links it to a limited extent, and effects on B cell number and B cell Ia, mIgM, and mIgD expression were observed. In most experiments, mice were pretreated with anti-interleukin 7 mAb to prevent the generation of new bone marrow B cells, and with anti-CD4 mAb to prevent the generation of T cell help. In some experiments, mice also received anti-Fc gamma RII mAb to prevent cross-linking of mIgD with Fc gamma RII, and cobra venom factor to prevent possible mIg-complement receptor interactions and complement-mediated killing of B cells. The results of these studies demonstrate that (a) even limited cross-linking of mIgD on mature B cells can lead to B cell death; (b) increased cross-linking of mIgD leads to increased B cell death; (c) the loss of B cells is first detected 2 d after anti-IgD mAb injection and increases during the subsequent 3 d; (d) sustained modulation of mIgD may be necessary to cause B cell death; (e) mIgMdull but not mIgMbright B cells are lost in mice injected with anti-IgD mAbs; and (f) T cell help prevents or minimizes B cell death.

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Cross-linking of Fc gamma receptor to surface immunoglobulin on B cells provides an inhibitory signal that closes the plasma membrane calcium channel

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)78139-3 ◽

1994 ◽

Vol 269 (15) ◽

pp. 11409-11416

Author(s):

M.L. Diegel ◽

B.M. Rankin ◽

J.B. Bolen ◽

P.M. Dubois ◽

P.A. Kiener

Keyword(s):

Plasma Membrane ◽

B Cells ◽

Calcium Channel ◽

Cross Linking ◽

Fc Gamma Receptor ◽

Inhibitory Signal ◽

Surface Immunoglobulin ◽

Gamma Receptor

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CD45-null transgenic mice reveal a positive regulatory role for CD45 in early thymocyte development, in the selection of CD4+CD8+ thymocytes, and B cell maturation.

Journal of Experimental Medicine ◽

10.1084/jem.183.4.1707 ◽

1996 ◽

Vol 183 (4) ◽

pp. 1707-1718 ◽

Cited By ~ 269

Author(s):

K F Byth ◽

L A Conroy ◽

S Howlett ◽

A J Smith ◽

J May ◽

...

Keyword(s):

Signal Transduction ◽

T Cell ◽

B Cells ◽

Transgenic Mice ◽

B Cell ◽

T Cell Development ◽

Cell Development ◽

Cross Linking ◽

Thymocyte Development ◽

Double Positive

The CD45 transmembrane glycoprotein has been shown to be a protein phosphotyrosine phosphatase and to be important in signal transduction in T and B lymphocytes. We have employed gene targeting to create a strain of transgenic mice that completely lacks expression of all isoforms of CD45. The spleens from CD45-null mice contain approximately twice the number of B cells and one fifth the number of T cells found in normal controls. The increase in B cell numbers is due to the specific expansion of two B cell subpopulations that express high levels of immunoglobulin (IgM) staining. T cell development is significantly inhibited in CD45-null animals at two distinct stages. The efficiency of the development of CD4-CD8- thymocytes into CD4+ CD8+ thymocytes is reduced by twofold, subsequently the frequency of successful maturation of the double positive population into mature, single positive thymocytes is reduced by a further four- to fivefold. In addition, we demonstrate that CD45-null thymocytes are severely impaired in their apoptotic response to cross-linking signals via T cell receptor (TCR) in fetal thymic organ culture. In contrast, apoptosis can be induced normally in CD45-null thymocytes by non-TCR-mediated signals. Since both positive and negative selection require signals through the TCR complex, these findings suggest that CD45 is an important regulator of signal transduction via the TCR complex at multiple stages of T cell development. CD45 is absolutely required for the transmission of mitogenic signals via IgM and IgD. By contrast, CD45-null B cells proliferate as well as wild-type cells to CD40-mediated signals. The proliferation of B cells in response to CD38 cross-linking is significantly reduced but not abolished by the CD45-null mutation. We conclude that CD45 is not required at any stage during the generation of mature peripheral B cells, however its loss reveals a previously unrecognized role for CD45 in the regulation of certain subpopulations of B cells.

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Vav proteins regulate peripheral B-cell survival

Blood ◽

10.1182/blood-2004-12-4894 ◽

2005 ◽

Vol 106 (7) ◽

pp. 2391-2398 ◽

Cited By ~ 33

Author(s):

Elena Vigorito ◽

Laure Gambardella ◽

Francesco Colucci ◽

Simon McAdam ◽

Martin Turner

Keyword(s):

B Cells ◽

B Cell ◽

Marginal Zone ◽

Cell Receptor ◽

Cross Linking ◽

Marginal Zone B Cells ◽

Survival Signal ◽

B Cell Survival ◽

Follicular B Cells ◽

Deficient Mice

AbstractMice lacking all 3 Vav proteins fail to produce significant numbers of recirculating follicular or marginal zone B cells. Those B cells that do mature have shortened lifespans. The constitutive nuclear factor-kappaB (NF-κB) activity of resting naive B cells required Vav function and expression of cellular reticuloendotheliosis (c-Rel). Rel-A was reduced in Vav-deficient B cells. Furthermore, expression of the NF-κB-regulated antiapoptotic genes A1 and Bcl-2 was reduced in mature Vav-deficient B cells. Overexpression of Bcl-2 restored the number of mature follicular B cells in the spleens of Vav-deficient mice. When activated by B-cell receptor (BCR) cross-linking, Vav-deficient B cells failed to activate NF-κB. Vav proteins thus regulate an NF-κB-dependent survival signal in naive B cells and are required for NF-κB function after BCR cross-linking.

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Association between B-lymphocyte membrane immunoglobulin and multiple members of the Src family of protein tyrosine kinases

Molecular and Cellular Biology ◽

10.1128/mcb.12.5.2315-2321.1992 ◽

1992 ◽

Vol 12 (5) ◽

pp. 2315-2321

Author(s):

M A Campbell ◽

B M Sefton

Keyword(s):

B Cells ◽

B Cell ◽

Tyrosine Kinases ◽

B Lymphocyte ◽

Protein Tyrosine Kinases ◽

Cell Type ◽

Protein Tyrosine ◽

Membrane Immunoglobulin ◽

Family Protein

Treatment of B lymphocytes with antibodies to membrane immunoglobulin (Ig) stimulates protein tyrosine phosphorylation. We have examined the phosphorylation in vitro of proteins associated with membrane Ig. The Src family protein tyrosine kinases p53/56lyn, p59fyn, and p56lck are associated with membrane Ig in spleen B cells and B-cell lines and undergo phosphorylation in vitro. The pattern of expression of Src family protein tyrosine kinases in B cells varied. Our studies suggest that multiple kinases can potentially interact with membrane Ig and that within any one B-cell type, all of the Src family kinases expressed can be found in association with membrane Ig. We also observed that the Ig-associated Ig alpha protein, multiple forms of Ig beta, and proteins of 100 and 25 kDa were tyrosine phosphorylated in vitro. The 100- and 25-kDa proteins remain unidentified.

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Cross-linking of CD80 and CD86 Diminishes Expression of CD54 on EBV-transformed B Cells through Inactivation of RhoA and Ras

Immune Network ◽

10.4110/in.2011.11.6.390 ◽

2011 ◽

Vol 11 (6) ◽

pp. 390

Author(s):

Ga Bin Park ◽

Yeong Seok Kim ◽

Hyunkeun Song ◽

Seonghan Kim ◽

Dong Man Park ◽

...

Keyword(s):

B Cells ◽

Cross Linking

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Cross-linking CD40 on B cells preferentially induces stress-activated protein kinases rather than mitogen-activated protein kinases.

The EMBO Journal ◽

10.1002/j.1460-2075.1996.tb00337.x ◽

1996 ◽

Vol 15 (1) ◽

pp. 92-101 ◽

Cited By ~ 123

Author(s):

I. Berberich ◽

G. Shu ◽

F. Siebelt ◽

J. R. Woodgett ◽

J. M. Kyriakis ◽

...

Keyword(s):

B Cells ◽

Protein Kinases ◽

Cross Linking ◽

Mitogen Activated Protein Kinases ◽

Mitogen Activated Protein

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Selective activation of p42 mitogen-activated protein (MAP) kinase in murine B lymphoma cell lines by membrane immunoglobulin cross-linking. Evidence for protein kinase C-independent and -dependent mechanisms of activation

Biochemical Journal ◽

10.1042/bj2870269 ◽

1992 ◽

Vol 287 (1) ◽

pp. 269-276 ◽

Cited By ~ 40

Author(s):

M R Gold ◽

J S Sanghera ◽

J Stewart ◽

S L Pelech

Keyword(s):

Map Kinase ◽

Tyrosine Phosphorylation ◽

Cell Lines ◽

Map Kinases ◽

Phorbol Esters ◽

Cross Linking ◽

Kinase Activation ◽

Membrane Immunoglobulin ◽

Protein Map ◽

Mitogen Activated Protein

Cross-linking of membrane immunoglobulin (mIg), the B lymphocyte antigen receptor, with anti-receptor antibodies stimulates tyrosine phosphorylation of a number of proteins, including one of 42 kDa. Proteins with a similar molecular mass are tyrosine-phosphorylated in response to receptor stimulation in other cell types and have been identified as serine/threonine kinases, termed mitogen-activated protein (MAP) kinases or extracellular signal-regulated kinases (ERKs). The MAP kinases constitute a family of related kinases, at least three of which have molecular masses of 40-45 kDa. In this paper we show that mIg cross-linking stimulated the myelin basic protein phosphotransferase activity characteristic of MAP kinase in both mature and immature murine B cell lines. This enzyme activity co-purified on three different columns with a 42 kDa protein that was tyrosine-phosphorylated (pp42) in response to mIg cross-linking and which reacted with a panel of anti-(MAP kinase) antibodies. Although immunoblotting with the anti-(MAP kinase) antibodies showed that these B cell lines expressed both 42 kDa and 44 kDa forms of MAP kinase, only the 42 kDa form was activated and tyrosine-phosphorylated to a significant extent. Activation of protein kinase C (PKC) with phorbol esters also resulted in selective tyrosine phosphorylation and activation of the 42 kDa MAP kinase. This suggested that mIg-induced MAP kinase activation could be due to stimulation of PKC by mIg. However, mIg-stimulated MAP kinase activation and pp42 tyrosine phosphorylation was only partially blocked by a PKC inhibitor, the staurosporine analogue Compound 3. In contrast, Compound 3 completely blocked the ability of phorbol esters to stimulate MAP kinase activity and induce tyrosine phosphorylation of pp42. Thus mIg may activate MAP kinase by both PKC-dependent and -independent mechanisms.

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Adenovirus vector infection of chronic lymphocytic leukemia B cells

Blood ◽

10.1182/blood.v88.12.4676.bloodjournal88124676 ◽

1996 ◽

Vol 88 (12) ◽

pp. 4676-4683 ◽

Cited By ~ 56

Author(s):

MJ Cantwell ◽

S Sharma ◽

T Friedmann ◽

TJ Kipps

Keyword(s):

B Cells ◽

Chronic Lymphocytic Leukemia ◽

Gene Transfer ◽

Hela Cells ◽

Recombinant Adenovirus ◽

Lymphocytic Leukemia ◽

Cross Linking ◽

Gene Transduction ◽

Transfer Genes ◽

Adenovirus Vectors

Adenovirus vectors have several features that make them attractive for potential use in gene therapy, including a broad tissue tropism and an ability to infect quiescent or postmitotic cells. In light of this, we examined whether recombinant adenovirus vectors could transfer genes into neoplastic cells of patients with chronic lymphocytic leukemia (CLL), a leukemia of “resting” B cells. Using high-titer recombinant adenovirus vectors, we found we could transfer genes encoding beta-galactosidase or murine CD80 (B7–1) into the CLL B cells of all patients tested (n = 10). The efficiency of gene transduction into CLL B cells was approximately 100 to 1,000-fold lower than into HeLa cells at any given multiplicity of infection (MOI). At a MOI of 500, 10% to 70% of the CLL B cells from different patients were made to express the transgene, as assessed by multiparameter flow cytometric analysis. Sustained levels of expression with little loss in the percentage of infected cells were maintained for up to 9 days, at which point the analysis was stopped. We found that CLL B cells have markedly lower expression levels of integrins that facilitate internalization of adenovirus particles into target cells, perhaps accounting, in part, for the reduced efficiency of adenovirus-mediated gene transfer compared with that in HeLa cells. Although HeLa cells express high levels of alpha(v)beta5, and detectable amounts of alpha(v)beta3, we find CLL cells from all patients tested express only low amounts of alpha(v)beta3, and no detectable alpha(v)beta5. Activation of CLL cells via CD40 cross-linking enhances expression of alpha(v)beta3, and induces expression of alpha(v)beta5. This phenotypic change is associated with a fivefold increase in the efficiency of adenovirus-mediated gene transfer into such activated CLL B cells. This study demonstrates that adenovirus vectors can transduce genes into CLL B cells and that the efficiency of gene transduction is enhanced by activation via CD40 cross-linking. This is the first demonstration that high proportions of CLL B cells can be made to express a selected transgene, suggesting that such gene transfer methods may become useful for the study of the pathogenesis and/or treatment of this disease.

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