scholarly journals CD5 is a potential selecting ligand for B cell surface immunoglobulin framework region sequences.

1996 ◽  
Vol 184 (4) ◽  
pp. 1279-1284 ◽  
Author(s):  
R Pospisil ◽  
M G Fitts ◽  
R G Mage
Keyword(s):  
B Cells ◽  
Cell Surface ◽  
B Cell ◽  
B Lymphocyte ◽  
Surface Glycoprotein ◽  
Cell Surface Glycoprotein ◽  
Surface Immunoglobulins ◽  
B Lymphocyte Development ◽  
Framework Region ◽  
Rabbit Appendix

In rabbits nearly all B lymphocytes express the glycoprotein CD5, in contrast to mice and humans, where only a small proportion of B cells express this molecule (Raman, C., and K.L. Knight. 1992. J. Immunol. 149:3858-3864). CD5+ B cells appear to develop early in ontogeny and be maintained throughout life by self-renewal. The function of CD5 on B cells is still unknown. We showed earlier that "positive" selection occurs during B lymphocyte development in the rabbit appendix. This selection favors B cell expressing surface immunoglobulins with VHa2 structures in the first and third framework regions (Pospisil, R., G.O. Young-Cooper, and R.G. Mage. 1995. Proc. Natl. Acad. Sci. USA. 92:6961-6965). Here we report that F(ab')2 fragments, especially those bearing VHa2 framework region determinants, specifically interact with the B cell-surface glycoprotein CD5. This interaction can be inhibited by anti-CD5 antibodies. Furthermore, immobilized F(ab')2 fragments selectively bind CD5 molecules in appendix cell lysates. Interactions of VH framework region structures with CD5 may affect maintenance and selective expansion of particular B cells and thus contribute to autostimulatory growth of autoimmune or transformed cells.

scholarly journals Hyaluronate-CD44 Interactions Can Induce Murine B-Cell Activation

Blood ◽  
1997 ◽  
Vol 89 (8) ◽  
pp. 2901-2908 ◽  
Author(s):  
Asimah Rafi ◽  
Mitzi Nagarkatti ◽  
Prakash S. Nagarkatti
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Critical Role ◽  
Surface Glycoprotein ◽  
B Cell Differentiation ◽  
B Cell Activation ◽  
Cell Surface Glycoprotein ◽  
Immunodeficient Mice

Abstract CD44 is a widely distributed cell surface glycoprotein whose principal ligand has been identified as hyaluronic acid (HA), a major component of the extracellular matrix (ECM). Recent studies have demonstrated that activation through CD44 leads to induction of effector function in T cells and macrophages. In the current study, we investigated whether HA or monoclonal antibodies (MoAbs) against CD44 would induce a proliferative response in mouse lymphocytes. Spleen cells from normal and nude, but not severe combined immunodeficient mice, exhibited strong proliferative responsiveness to stimulation with soluble HA or anti-CD44 MoAbs. Furthermore, purified B cells, but not T cells, were found to respond to HA. HA was unable to stimulate T cells even in the presence of antigen presenting cells (APC) and was unable to act as a costimulus in the presence of mitogenic or submitogenic concentrations of anti-CD3 MoAbs. In contrast, stimulation of B cells with HA in vitro, led to B-cell differentiation as measured by production of IgM antibodies in addition to increased expression of CD44 and decreased levels of CD45R. The fact that the B cells were responding directly to HA through its binding to CD44 and not to any contaminants or endotoxins was demonstrated by the fact that F(ab)2 fragments of anti-CD44 MoAbs or soluble CD44 fusion proteins could significantly inhibit the HA-induced proliferation of B cells. Also, HA-induced proliferation of B cells was not affected by the addition of polymixin B, and B cells from lipopolysaccharide (LPS)-unresponsive C3H/HeJ strain responded strongly to stimulation with HA. Furthermore, HA, but not chondroitin-sulfate, another major component of the ECM, induced B-cell activation. It was also noted that injection of HA intraperitoneally, triggered splenic B cell proliferation in vivo. Together, the current study demonstrates that interaction between HA and CD44 can regulate murine B-cell effector functions and that such interactions may play a critical role during normal or autoimmune responsiveness of B cells.

scholarly journals Molecular characterization and expression of a novel human leukocyte cell-surface marker homologous to mouse Ly-9

Blood ◽  
2001 ◽  
Vol 97 (11) ◽  
pp. 3513-3520 ◽  
Author(s):  
Miguel Angel de la Fuente ◽  
Victoria Tovar ◽  
Neus Villamor ◽  
Nuria Zapater ◽  
Pilar Pizcueta ◽  
...  
Keyword(s):  
Cell Surface ◽  
B Cell ◽  
Cell Line ◽  
B Lymphocytes ◽  
Full Length ◽  
Surface Glycoprotein ◽  
T And B Lymphocytes ◽  
Cdna Clones ◽  
Cell Surface Glycoprotein ◽  
Full Length Cdna

Ly-9 is a mouse cell-surface glycoprotein that is selectively expressed on thymocytes and on mature T and B lymphocytes. Ly-9 belongs to the CD2 subset of the immunoglobulin superfamily, an emerging family of cell signaling receptors. Recently, a partial human Ly-9 complementary DNA (cDNA) sequence has been described. Full-length cDNA clones were isolated that included the initiation codon, the sequence encoding the full signal peptide, and 14 amino acids more in the cytoplasmic domain than in the previously reported clone. The predicted extracellular domain of human Ly-9 contains 4 immunoglobulinlike domains, similar to those in mouse Ly-9. Northern blot analysis revealed that the human Ly-9 messenger RNA (2.6 kb) is expressed predominantly in lymph node, spleen, thymus, and peripheral blood leukocytes. Four monoclonal antibodies (mAbs) were raised against human Ly-9 by immunizing mice with the pre-B-cell line 300.19 stably transfected with human Ly-9 full-length cDNA. These mAbs strongly stained the surfaces of cells transfected with human Ly-9 cDNA but not of untransfected cells. Human Ly-9 expression was restricted to T and B lymphocytes and thymocytes, with the highest levels of expression on CD4+CD8− and CD4−CD8+ thymocytes. Monocytes, granulocytes, platelets, and red blood cells were uniformly negative for Ly-9. These mAbs immunoprecipitated major polypeptides of 120 kd from the transfected cells and 120 kd and 100 kd from B-cell line Daudi, probably because of the cell-surface–expressed isoforms. These data demonstrate that human Ly-9 is a new marker for the study of normal and malignant leukocytes.

Specific binding of Fyn and phosphatidylinositol 3-kinase to the B cell surface glycoprotein CD19 through their src homology 2 domains

1995 ◽  
Vol 25 (10) ◽  
pp. 2978-2984 ◽  
Author(s):  
N. Jan Chalupny ◽  
Alejandro Aruffo ◽  
James M. Esselstyn ◽  
Po-Ying Chan ◽  
Jürgen Bajorath ◽  
...  
Keyword(s):  
Cell Surface ◽  
B Cell ◽  
Specific Binding ◽  
Surface Glycoprotein ◽  
Phosphatidylinositol 3 Kinase ◽  
Cell Surface Glycoprotein ◽  
Src Homology 2 ◽  
Src Homology ◽  
Phosphatidylinositol 3

scholarly journals Analysis of Mice with Single and Multiple Copies of Transgenes Reveals a Novel Arrangement for the λ5-VpreB1 Locus Control Region

1999 ◽  
Vol 19 (1) ◽  
pp. 671-679 ◽  
Author(s):  
Pierangela Sabbattini ◽  
Andrew Georgiou ◽  
Calum Sinclair ◽  
Niall Dillon
Keyword(s):  
B Cells ◽  
B Cell ◽  
Control Region ◽  
B Lymphocyte ◽  
Locus Control Region ◽  
Cell Receptor ◽  
Hypersensitive Sites ◽  
Multiple Copies ◽  
Expression Behavior ◽  
B Lymphocyte Development

ABSTRACT The murine λ5-V preB1 locus encodes two proteins that form part of the pre-B-cell receptor and play a key role in B-lymphocyte development. We have identified a locus control region (LCR) which is responsible for coordinate activation of both genes in pre-B cells. Analysis of mice with single and multiple copies of transgenes shows a clear difference in the expression behavior of the genes depending on the transgene copy number. While expression of both λ5 and V preB1 in single- and two-copy integrations requires the presence of a set of DNase I hypersensitive sites located 3′ of the λ5 gene, small fragments containing the genes have LCR activity when arranged in multiple-copy tandem arrays, indicating that additional components of the LCR are located within or close to the genes. The complete LCR is capable of driving efficient copy-dependent expression of a λ5 gene in pre-B cells even when it is integrated into centomeric γ-satellite DNA. The finding that activation of expression of the locus by positively acting factors is fully dominant over the silencing effect of heterochromatin has implications for models for chromatin-mediated gene silencing during B-cell development.

scholarly journals Regulation of B Lymphocyte Development by Histone H2A Deubiquitinase BAP1

2021 ◽  
Vol 12 ◽  
Author(s):  
Yun Hsiao Lin ◽  
Yue Liang ◽  
HanChen Wang ◽  
Lin Tze Tung ◽  
Michael Förster ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Cycle Progression ◽  
B Lymphocyte ◽  
Cell Development ◽  
B Cell Development ◽  
Lymphocyte Development ◽  
A Cell ◽  
B Lymphocyte Development

BAP1 is a deubiquitinase (DUB) of the Ubiquitin C-terminal Hydrolase (UCH) family that regulates gene expression and other cellular processes, via deubiquitination of histone H2AK119ub and other substrates. BAP1 is an important tumor suppressor in human, expressed and functional across many cell-types and tissues, including those of the immune system. B lymphocytes are the mediators of humoral immune response, however the role of BAP1 in B cell development and physiology remains poorly understood. Here we characterize a mouse line with a selective deletion of BAP1 within the B cell lineage (Bap1fl/fl mb1-Cre) and establish a cell intrinsic role of BAP1 in the regulation of B cell development. We demonstrate a depletion of large pre-B cells, transitional B cells, and mature B cells in Bap1fl/fl mb1-Cre mice. We characterize broad transcriptional changes in BAP1-deficient pre-B cells, map BAP1 binding across the genome, and analyze the effects of BAP1-loss on histone H2AK119ub levels and distribution. Overall, our work establishes a cell intrinsic role of BAP1 in B lymphocyte development, and suggests its contribution to the regulation of the transcriptional programs of cell cycle progression, via the deubiquitination of histone H2AK119ub.

Identification of a cell-surface glycoprotein mediating cell adhesion in EBV-immortalized normal B cells

1986 ◽  
Vol 38 (4) ◽  
pp. 539-547 ◽  
Author(s):  
Manuel Patarroyo ◽  
Patrick G. Beatty ◽  
Kenneth Nilsson ◽  
Carl G. Gahmberg
Keyword(s):  
Cell Adhesion ◽  
B Cells ◽  
Cell Surface ◽  
Surface Glycoprotein ◽  
Cell Surface Glycoprotein ◽  
A Cell

scholarly journals B-lymphocyte development is regulated by the combined dosage of three basic helix-loop-helix genes, E2A, E2-2, and HEB.

1996 ◽  
Vol 16 (6) ◽  
pp. 2898-2905 ◽  
Author(s):  
Y Zhuang ◽  
P Cheng ◽  
H Weintraub
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocyte ◽  
Cell Lineage ◽  
Lymphocyte Development ◽  
Normal Numbers ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
B Lymphocyte Development ◽  
Essential Function

B-lymphocyte development requires the basic helix-loop-helix proteins encoded by the E2A gene. In this study, the control mechanism of E2A was further explored by disruption of the E2A-related genes, E2-2 and HEB. In contrast to E2A, E2-2 and HEB are not essential for the establishment of the B-cell lineage. However, both E2-2 and HEB are required for the generation of the normal numbers of pro-B cells in mouse embryos. Breeding tests among mice carrying different mutations revealed that E2-2 and HEB interact with E2A in many developmental processes including generation of B cells. Specifically, mice transheterozygous for any two mutations of these three genes produced fewer pro-B cells than the singly heterozygous littermates. This study indicates that B-cell development is dependent not only on an essential function provided by the E2A gene but also on a combined dosage set by E2A, E2-2, and HEB.

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