scholarly journals Functional analyses of thymic CD5+ B cells. Responsiveness to major histocompatibility complex class II-restricted T blasts but not to lipopolysaccharide or anti-IgM plus interleukin 4.

1990 ◽  
Vol 171 (1) ◽  
pp. 321-326 ◽  
Author(s):  
M Inaba ◽  
K Inaba ◽  
Y Adachi ◽  
K Nango ◽  
H Ogata ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Antibody Formation ◽  
Direct Interaction ◽  
Interleukin 4 ◽  
In Vitro Assays ◽  
B Cell Growth Factor ◽  
A Cell ◽  
Functional Analyses

The function of thymic B cells in several standard in vitro assays was investigated. Thymic B cells, 75% of which were CD5+, showed a poor responsiveness to the mitogens LPS or anti-mu plus IL-4. Both proliferation and antibody formation were much lower in thymic than splenic B cell cultures. However, CD5- B cells purified using a cell sorter responded well to B cell stimulants, whereas purified CD5+ thymic B cells did not, indicating that CD5+ thymic B cells were unresponsive to B cell growth factor or LPS. Thymic B cells could be activated polyclonally by direct interaction with alloreactive T blasts, as manifested by DNA synthesis and antibody formation. These findings indicate that CD5+ thymic B cells may not be stimulated via sIg and IL-4, but require instead direct interaction with T blasts.

Enhanced B Cell Activation in the Absence of CD81

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2578-2578
Author(s):  
Mrinmoy Sanyal ◽  
Rosemary Fernandez ◽  
Shoshana Levy
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Cell Receptor ◽  
Free Calcium ◽  
B Cell Activation ◽  
Membrane Reorganization ◽  
A Cell

Abstract CD81 is a component of the CD19/CD21 coreceptor complex in B cells. This tetraspanin molecule was previously shown to enable membrane reorganization in B cells responding to complement-bound antigens. Here we stimulated B cells via their B cell receptor (BCR) and demonstrate that Cd81−/− B cells fluxed higher intracellular free calcium ion along with increased phosphorylation of PLCγ2 and Syk. The stimulated Cd81−/− B cells also proliferated faster and secreted higher amounts of antibodies. Moreover, activation of the TLR4 pathway in Cd81−/− B cells induced increased proliferation and antibody secretion. Furthermore, Cd81−/− mice mounted a significantly higher immune response to T-cell independent antigens than their wildtype counterparts. Finally, analysis of Cd81−/− B cells that were generated by bone marrow transplantation into Rag1−/− mice confirmed a cell intrinsic hyperactive phenotype. Taken together, these results indicate that CD81 plays a negative role in B cell activation in vitro and in vivo.

The development of functional B lymphocytes in conditional PU.1 knock-out mice

Blood ◽  
2005 ◽  
Vol 106 (6) ◽  
pp. 2083-2090 ◽  
Author(s):  
Matthew Polli ◽  
Aleksandar Dakic ◽  
Amanda Light ◽  
Li Wu ◽  
David M. Tarlinton ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Fetal Liver ◽  
Cell Receptor ◽  
Interleukin 4 ◽  
Knock Out ◽  
B Lineage ◽  
And Function

Abstract An abundance of research has entrenched the view that the Ets domain containing transcription factor PU.1 is fundamental to the development and function of B lymphocytes. In this study, we have made use of a conditional PU.1 allele to test this notion. Complete deletion of PU.1 resulted in the loss of B cells and all other lineage-positive cells in the fetal liver and death between E18.5 and birth; however, specific deletion of PU.1 in the B lineage had no effect on B-cell development. Furthermore, deletion of PU.1 in B cells did not compromise their ability to establish and maintain an immune response. An increased level of apoptosis was observed in vitro upon B-cell receptor (BCR) cross-linking; however, this was partially rescued by interleukin-4 (IL-4). These findings suggest that PU.1 is not essential for the development of functional B lymphocytes beyond the pre-B stage. (Blood. 2005;106:2083-2090)

scholarly journals Expression of interleukin-4 receptors on early human B-lineage cells

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 703-710 ◽  
Author(s):  
CL Law ◽  
RJ Armitage ◽  
JG Villablanca ◽  
TW LeBien
Keyword(s):  
Bone Marrow ◽  
B Cell ◽  
Constitutive Expression ◽  
Lymphoid Cells ◽  
Interleukin 4 ◽  
B Cell Differentiation ◽  
Fluorescent Intensity ◽  
B Cell Growth Factor ◽  
B Lineage

Interleukin-4 (IL-4) regulates multiple stages of the antigen-dependent phase of B-cell development. However, its precise role in regulating B lymphopoiesis in bone marrow is not as well defined. We examined whether surface IgM- normal and leukemic human B-cell precursors (BCP) expressed IL-4 receptors using biotinylated IL-4. Constitutive expression of IL-4 receptors was detected on both normal and leukemic BCP. A higher percentage of normal BCP (82% +/- 15%) expressed IL-4 receptors compared with leukemic BCP (44% +/- 8%). Using mean fluorescent intensity as an indicator of receptor level on the IL-4 receptor positive cells, normal (91 +/- 41) and leukemic (44 +/- 37) BCP expressed comparable numbers of receptors. IL-4 induced the expression of CD23 on 30% of the leukemic BCP cases examined. IL-4 induced CD23 on surface IgM+ fetal bone marrow lymphoid cells but not on the surface IgM- normal BCP, despite the presence of detectable receptors on the surface IgM- cells. IL-4 did not stimulate proliferation of normal BCP, nor could it enhance the effect of recombinant IL-7 or low molecular weight B-cell growth factor. However, IL-4 increased the expression of surface IgM and surface Ig kappa on in vitro differentiated pre-B cells. Our collective results identify no role for IL-4 in the proliferation of normal or leukemic BCP, but identify a role in the enhancement of surface Ig expression during pre- B to B-cell differentiation.

Retinoic Acid Inhibits CD40 + Interleukin-4–Mediated IgE Production In Vitro

Blood ◽  
1998 ◽  
Vol 92 (5) ◽  
pp. 1713-1720 ◽  
Author(s):  
M. Worm ◽  
J.M. Krah ◽  
R.A. Manz ◽  
B.M. Henz
Keyword(s):  
Retinoic Acid ◽  
B Cells ◽  
B Cell ◽  
Mononuclear Cells ◽  
Interleukin 4 ◽  
Dependent Manner ◽  
Maximal Inhibition ◽  
Ige Synthesis ◽  
Dose Dependent

Abstract To elucidate the role of retinoic acid (RA) in anti-CD40 + interleukin-4 (IL-4)–mediated B-cell activation, the effect of 10−12 to 10−6 mol/L RA was studied in anti-CD40 (1 μg/mL) + IL-4 (5 ng/mL)-mediated proliferation and Ig synthesis by human peripheral blood mononuclear cells (PBMC) and B cells in healthy donors. Anti-CD40 + IL-4–mediated proliferation of PBMC and B cells was inhibited by RA in a dose-dependent manner, with maximal inhibition of 62% ± 5% in PBMC and 55% ± 4.4% in B cells by all-trans RA, and 58% ± 6.7% and 51% ± 4.7%, respectively by 13-cis RA. IgE synthesis was even more markedly inhibited by RA starting at concentrations of >10−14mol/L for B cells and >10−10 mol/L for PBMC. Maximal inhibition of IgE production for B cells was at 10−8mol/L for all-trans RA (94% ± 1.8%) and 96% ± 3.2% for 13-cis RA. Low concentrations of RA inhibiting IgE synthesis (10−10 mol/L) affected neither B-cell proliferation nor the production of IgA, IgG, and IgM. Elucidation of the mechanism involved in this inhibition of IgE production shows that epsilon germline transcription is decreased by RA, whereas production of interferon-γ (IFN-γ) was not enhanced in the presence of RA. To differentiate whether the RA effect was mediated by RA receptors , β, and γ, the expression of the retinoic acid receptors (RAR) was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The data show that unstimulated human peripheral B cells express mRNA of the RA receptor , β, and γ. Using retinoids with different receptor binding specificity (CD336, CD437, CD2019, CD367), dose-dependent inhibition of IgE synthesis was shown by all four derivates, but was most marked by an RA binding the  receptor with high specificity. Taken together, this study shows that RA inhibits IgE production of anti-CD40 + IL-4–stimulated B cells in vitro. © 1998 by The American Society of Hematology.

scholarly journals Responsiveness of chronic lymphocytic leukemia B cells activated via surface Igs or CD40 to B-cell tropic factors

Blood ◽  
1992 ◽  
Vol 80 (12) ◽  
pp. 3173-3181
Author(s):  
AC Fluckiger ◽  
JF Rossi ◽  
A Bussel ◽  
P Bryon ◽  
J Banchereau ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Lymphocytic Leukemia ◽  
Interleukin 4 ◽  
Aureus Strain ◽  
Cross Linking ◽  
Cell Recovery

Recent studies performed in the laboratory have established that interleukin-4 (IL-4) used in combination with anti-CD40 monoclonal antibody (MoAb) 89 presented on Ltk- mouse fibroblasts stably expressing human Fc gamma RII/CDw32 (referred to as the CD40 system) sustains long-term proliferation of normal human B cells. In the present study, B-cell chronic lymphocytic leukemias (B-CLLs) activated through slgs or CD40 were examined for their capacity to proliferate and differentiate in response to various cytokines. Our results indicate that the outcome of IL-4 stimulation on the in vitro growth of B-CLL depends on the signalling pathway used for their activation. Whereas IL-4 did not display any growth-stimulatory effect on B-CLL activated by Ig cross-linking agents, it could stimulate DNA synthesis and enhance the viable cell recovery when leukemic B cells were cultured in the CD40 system. Most B-CLL samples were induced for IgM synthesis upon Staphylococcus aureus strain Cowan I stimulation. This Ig response was potentiated by IL-2 and antagonized by IL-4. Anti-CD40 MoAb used alone or in combination with cytokines (IL-1 alpha to IL-6, interferon gamma, tumor necrosis factor gamma, and transforming growth factor beta) failed to induce Ig secretion from B-CLL cells. No evidence for Ig isotype switching was obtained with the cytokines listed above, regardless of the mode of activation. Taken together, our results suggest that B-CLL cells can be partially released from their apparent maturation block by IL-2 and Ig cross-linking agents. In contrast, combinations of IL-4 and cross-linked anti-CD40 antibodies induced entry of B-CLL cell into cycle, but poorly stimulated their differentiation into Ig secreting cells.

scholarly journals Relationships between B cell and myeloid differentiation. Studies with a B lymphocyte progenitor line, HAFTL-1.

1988 ◽  
Vol 168 (1) ◽  
pp. 389-407 ◽  
Author(s):  
W F Davidson ◽  
J H Pierce ◽  
S Rudikoff ◽  
H C Morse
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocyte ◽  
Fetal Liver ◽  
Nonspecific Esterase ◽  
B Cell Differentiation ◽  
Monocytes And Macrophages ◽  
A Cell ◽  
Esterase Production

A cell line, HAFTL-1, derived by in vitro transformation of fetal liver cells with v-Ha-ras, was found to have molecular and phenotypic characteristics of pro-B cells recently committed to the Ly-1+ B cell differentiation pathway. Stimulation of these cells with LPS resulted in their differentiation within either the B or myelomonocytic lineages. Thus, lines derived from LPS-stimulated HAFTL-1 cells were shown to be clonally related, as evidenced by common v-ras integrations, but to exhibit characteristics of pre-B cells (ThB expression, continuing DJ heavy chain rearrangements) or mature macrophages (expression of Mac-1 and Mac-2, lysozyme and nonspecific esterase production, phagocytosis) while maintaining their Ly-1+ phenotype. These results suggest that events resulting in the irrevocable commitment to a single lineage occur late in differentiation, at least within the pathway yielding Ly-1+ B cells and a proposed subpopulation of Ly-1+ monocytes and macrophages. Final commitment to these lineages is carefully orchestrated, as evidenced by restricted expression of Ly-5 isoforms and production of IgH transcripts.

Stat5a/b contribute to interleukin 7–induced B-cell precursor expansion, but abl- andbcr/abl-induced transformation are independent of Stat5

Blood ◽  
2000 ◽  
Vol 96 (6) ◽  
pp. 2277-2283 ◽  
Author(s):  
Veronika Sexl ◽  
Roland Piekorz ◽  
Richard Moriggl ◽  
Juerg Rohrer ◽  
Michael P. Brown ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Interleukin 4 ◽  
Target Cells ◽  
Interleukin 7 ◽  
And Function ◽  
Deficient Mice

Abstract The cytokines interleukin 7 (IL-7) and interleukin 4 (IL-4) regulate lymphoid differentiation and function and activate the transcription factor Stat5. Using mice deficient for the 2 highly related transcription factors, Stat5a and Stat5b (Stat5a/b−/−), we investigated the role of Stat5 for B-cell differentiation, expansion, and function. Peripheral blood B cells of Stat5-deficient mice are significantly reduced, but no proliferation defects in response to various mitogenic stimuli are found. Also, IgM and IgG1 antibody production and immunoglobulin class switching are not affected. Pre- and pro-B cells of Stat5-deficient animals were found to have reduced responses to IL-7. Pro- and pre-B cells are the target cells of the abloncogene and numerous studies have suggested that Stat5a/b is essential for transformation by derivatives of the Abelson(abl) gene. To assess the role of Stat5a/b in transformation, we have evaluated the ability of variousabl derivatives to transform cells from Stat5a/b-deficient mice in vitro or in vivo. We demonstrate that the absence of Stat5a/b is not essential for the induction of lymphoid or myeloid tumors in vivo or on the ability to transform bone marrow cells in vitro.

scholarly journals Expression of interleukin-4 receptors on early human B-lineage cells

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 703-710 ◽  
Author(s):  
CL Law ◽  
RJ Armitage ◽  
JG Villablanca ◽  
TW LeBien
Keyword(s):  
Bone Marrow ◽  
B Cell ◽  
Constitutive Expression ◽  
Lymphoid Cells ◽  
Interleukin 4 ◽  
B Cell Differentiation ◽  
Fluorescent Intensity ◽  
B Cell Growth Factor ◽  
B Lineage

Abstract Interleukin-4 (IL-4) regulates multiple stages of the antigen-dependent phase of B-cell development. However, its precise role in regulating B lymphopoiesis in bone marrow is not as well defined. We examined whether surface IgM- normal and leukemic human B-cell precursors (BCP) expressed IL-4 receptors using biotinylated IL-4. Constitutive expression of IL-4 receptors was detected on both normal and leukemic BCP. A higher percentage of normal BCP (82% +/- 15%) expressed IL-4 receptors compared with leukemic BCP (44% +/- 8%). Using mean fluorescent intensity as an indicator of receptor level on the IL-4 receptor positive cells, normal (91 +/- 41) and leukemic (44 +/- 37) BCP expressed comparable numbers of receptors. IL-4 induced the expression of CD23 on 30% of the leukemic BCP cases examined. IL-4 induced CD23 on surface IgM+ fetal bone marrow lymphoid cells but not on the surface IgM- normal BCP, despite the presence of detectable receptors on the surface IgM- cells. IL-4 did not stimulate proliferation of normal BCP, nor could it enhance the effect of recombinant IL-7 or low molecular weight B-cell growth factor. However, IL-4 increased the expression of surface IgM and surface Ig kappa on in vitro differentiated pre-B cells. Our collective results identify no role for IL-4 in the proliferation of normal or leukemic BCP, but identify a role in the enhancement of surface Ig expression during pre- B to B-cell differentiation.

scholarly journals Association of CXCR4 with IgM and IgD BCR Isotypes: Role in B Cell Malignancies

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1852-1852
Author(s):  
Eva Gentner ◽  
Andrea Nicola Mazzarello ◽  
Martin Becker ◽  
Antonella Nicolò ◽  
Valerio Renna ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cytoplasmic Tail ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
In Vitro Assays ◽  
B Cell Malignancies ◽  
Cxcr4 Signaling

Abstract B cell malignancies including chronic lymphocytic leukemia (CLL) and diffuse large B cell lymphoma (DLBCL) are age-associated diseases driven by clonal B cell proliferation. Signaling through B cell antigen receptor (BCRs) is dysregulated in these diseases. In addition to BCRs, chemokine receptors, such as CXCR4 and CXCR5, are used to predict clinical course. The chemokine receptor CXCR4 is expressed at different developmental stages of B cells, serving different homeostatic functions including migration. We previously reported that the cross-talk of CXCR4 and the BCR isotype IgD is supporting survival and activation of mature B cells in mice. In this process, the B cell marker and co-activator CD19 plays a pivotal role. Nevertheless, interaction of BCR with CXCR4 has not been analyzed in detail in B cell malignancies. In this study, we further elucidated the CXCR4 signaling in mouse as well as human B cell subsets including immature and mature B cells. Consistent with murine B cells, CXCR4 signaling in human B cells from healthy donors remains tightly linked to surface IgD-BCR expression, although CXCR4 is highly expressed in human IgG positive memory B cell compartment. Furthermore, proximity of CXCR4 and IgD in human mature B cells is reminiscent of that of mouse B cells. In contrast, IgD:CXCR4 proximity is skewed towards IgM:CXCR4 in CLL cells. In in vitro assays, unmutated (U)-CLL cells migrate better compared to mutated (M)-CLL. Nevertheless, our analyses reveal a frequent association of IgM:CXCR4 in M-CLL. Taking together our murine and human data, we propose that IgD:CXCR4 association is crucial for CXCR4 signaling in both CLL and healthy B cells. Apart from CXCR4, mutations within the immunoreceptor tyrosine-based activation motif (ITAM) residues of CD79a and CD79b are frequently associated with B cell malignancies including DLBCL. Knowing the potential role of BCR and its isotypes in CXCR4 induced signaling, we further analyzed the role of CD79a and CD79b. Here, we took advantage of transgenic mice, whose CD79a and CD79b cytoplasmic tails carrying ITAM motifs can be inducibly deleted. Our analysis reveals the indispensable role of the CD79b cytoplasmic tail, whose loss of function causes complete impairment of CXCR4 induced signaling in murine B cells. In contrast, loss of CD79a cytoplasmic tail partially blocks CXCR4 induced signaling, which could be rescued by CD19 co-stimulation. Extending our murine results, we established an in vitro read-out system to test the role of ITAM mutants derived from DLBCLs, as well as DLBCL-derived isotypes for analyzing their impact on CXCR4 signaling. Taking our findings together, IgD:CXCR4 association is crucial for CXCR4 signaling in CLL and healthy B cells. An increased association of IgM:CXCR4 in M-CLL compared to U-CLL suggests the necessity of IgD:CXCR4 for functional CXCR4 signaling. Furthermore, CD79b is crucial for CXCR4 induced signaling in mature B cells and loss of CD79b function abrogates CXCR4 signaling in mature B cells. Disclosures Chiorazzi: AR Pharma: Equity Ownership; Janssen, Inc: Consultancy.

Retinoic Acid Inhibits CD40 + Interleukin-4–Mediated IgE Production In Vitro

Blood ◽  
1998 ◽  
Vol 92 (5) ◽  
pp. 1713-1720 ◽  
Author(s):  
M. Worm ◽  
J.M. Krah ◽  
R.A. Manz ◽  
B.M. Henz
Keyword(s):  
Retinoic Acid ◽  
B Cells ◽  
B Cell ◽  
Mononuclear Cells ◽  
Interleukin 4 ◽  
Dependent Manner ◽  
Maximal Inhibition ◽  
Ige Synthesis ◽  
Dose Dependent

To elucidate the role of retinoic acid (RA) in anti-CD40 + interleukin-4 (IL-4)–mediated B-cell activation, the effect of 10−12 to 10−6 mol/L RA was studied in anti-CD40 (1 μg/mL) + IL-4 (5 ng/mL)-mediated proliferation and Ig synthesis by human peripheral blood mononuclear cells (PBMC) and B cells in healthy donors. Anti-CD40 + IL-4–mediated proliferation of PBMC and B cells was inhibited by RA in a dose-dependent manner, with maximal inhibition of 62% ± 5% in PBMC and 55% ± 4.4% in B cells by all-trans RA, and 58% ± 6.7% and 51% ± 4.7%, respectively by 13-cis RA. IgE synthesis was even more markedly inhibited by RA starting at concentrations of >10−14mol/L for B cells and >10−10 mol/L for PBMC. Maximal inhibition of IgE production for B cells was at 10−8mol/L for all-trans RA (94% ± 1.8%) and 96% ± 3.2% for 13-cis RA. Low concentrations of RA inhibiting IgE synthesis (10−10 mol/L) affected neither B-cell proliferation nor the production of IgA, IgG, and IgM. Elucidation of the mechanism involved in this inhibition of IgE production shows that epsilon germline transcription is decreased by RA, whereas production of interferon-γ (IFN-γ) was not enhanced in the presence of RA. To differentiate whether the RA effect was mediated by RA receptors , β, and γ, the expression of the retinoic acid receptors (RAR) was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The data show that unstimulated human peripheral B cells express mRNA of the RA receptor , β, and γ. Using retinoids with different receptor binding specificity (CD336, CD437, CD2019, CD367), dose-dependent inhibition of IgE synthesis was shown by all four derivates, but was most marked by an RA binding the  receptor with high specificity. Taken together, this study shows that RA inhibits IgE production of anti-CD40 + IL-4–stimulated B cells in vitro. © 1998 by The American Society of Hematology.

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