scholarly journals Selective inhibition of growth factor-dependent human B cell proliferation by monoclonal antibody AB1 to an antigen expressed by activated B cells.

1984 ◽  
Vol 160 (6) ◽  
pp. 1919-1924 ◽  
Author(s):  
L K Jung ◽  
S M Fu
Keyword(s):  
Monoclonal Antibody ◽  
Cell Proliferation ◽  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Leukemic Cells ◽  
Activated T Cells ◽  
Igm Antibodies ◽  
Stimulatory Factor ◽  
Activated B Cells

A monoclonal antibody, AB1, was established with activated human B cells as immunogen. AB1 stained activated B cells but not activated T cells. Its selective reactivity to activated B cells was further documented by its nonreactivity to activated T cells, resting T and B cells, monocytes, granulocytes, bone marrow cells, leukemic cells, and cells from cell lines of T, B, and myeloid lineages. Upon activation, the antigen appeared on B cells as early as 3-4 h after stimulation and was fully expressed by 38 h. The expression of this antigen was not dependent on the presence of B cell stimulatory factor(s). Anti-IgM antibodies by themselves induced its expression. AB1 inhibited B cell proliferation that was induced by a low dose anti-IgM antibody and conditioned medium containing B cell stimulatory factor. It did not inhibit B cell proliferation induced by either high doses of anti-IgM antibodies or by formalinized Staphylococcus aureus. It also failed to inhibit T cell mitogenesis. The possibility exists that this antigen is related to the receptor for B cell stimulatory factor.

scholarly journals Activated B cells express receptors for, and proliferate in response to, pure interleukin 2.

1984 ◽  
Vol 160 (4) ◽  
pp. 1170-1183 ◽  
Author(s):  
R H Zubler ◽  
J W Lowenthal ◽  
F Erard ◽  
N Hashimoto ◽  
R Devos ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Interleukin 2 ◽  
T Helper ◽  
Spleen Cells ◽  
Human Spleen ◽  
Apparent Dissociation Constant ◽  
Activated B Cells

In this study we investigated whether interleukin 2 (IL-2) acts on B cell proliferation and whether activated B cells express IL-2 receptors. First, the functional activity of immunoaffinity-purified or recombinant human IL-2 was studied in a B blast assay using positively selected murine surface Ig-positive cells that had been activated by lipopolysaccharide (LPS) plus anti-Ig antibodies (anti-Ig). In this assay, T cells were not detected by fluorescence-activated cell sorter analysis. It was found that both IL-2 preparations led to optimal B cell proliferation compared with supernatants obtained from murine or human spleen cells or murine cloned T helper cells. Second, we observed that the IL-2 requirement in this assay was about the same as in a proliferation assay using lectin-activated polyclonal murine Lyt-2-positive T cells. Third, analysis of the binding of radiolabeled immunoaffinity-purified IL-2 to B cells indicated that LPS plus anti-Ig-activated B cells expressed a mean of 3,500 IL-2 receptors per cell with an apparent dissociation constant of 150 pM. However, neither nonactivated B cells nor B cells activated by LPS alone exhibited significant specific IL-2 binding. The functional and the receptor data are consistent with the conclusion that IL-2 is a growth factor not only for T cells but also for B cells.

A monoclonal antibody (MUM1p) detects expression of the MUM1/IRF4 protein in a subset of germinal center B cells, plasma cells, and activated T cells

Blood ◽  
2000 ◽  
Vol 95 (6) ◽  
pp. 2084-2092 ◽  
Author(s):  
Brunangelo Falini ◽  
Marco Fizzotti ◽  
Alessandra Pucciarini ◽  
Barbara Bigerna ◽  
Teresa Marafioti ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
T Cells ◽  
B Cells ◽  
B Cell ◽  
T Cell Activation ◽  
Germinal Center ◽  
Plasma Cells ◽  
Pcr Analysis ◽  
Homologous Gene ◽  
Activated T Cells

Abstract A new monoclonal antibody (MUM1p) was used to study the cell/tissue expression of human MUM1/IRF4 protein, the product of the homologous gene involved in the myeloma-associated t(6;14) (p25;q32). MUM1 was expressed in the nuclei and cytoplasm of plasma cells and a small percentage of germinal center (GC) B cells mainly located in the “light zone.” Its morphologic spectrum ranged from that of centrocyte to that of a plasmablast/plasma cell, and it displayed a phenotype (MUM1+/Bcl-6−/Ki67−) different from that of most GC B cells (MUM1−/Bcl-6+/Ki67+) and mantle B cells (MUM1−/Bcl-6−/Ki67−). Polymerase chain reaction (PCR) analysis of single MUM1+cells isolated from GCs showed that they contained rearranged Ig heavy chain genes with a varying number of VHsomatic mutations. These findings suggest that these cells may represent surviving centrocytes and their progeny committed to exit GC and to differentiate into plasma cells. MUM1 was strongly expressed in lymphoplasmacytoid lymphoma, multiple myeloma, and approximately 75% of diffuse large B-cell lymphomas (DLCL-B). Unlike normal GC B cells, in which the expression of MUM1 and Bcl-6 were mutually exclusive, tumor cells in approximately 50% of MUM1+ DLCL-B coexpressed MUM1 and Bcl-6, suggesting that expression of these proteins may be deregulated. In keeping with their proposed origin from GC B cells, Hodgkin and Reed–Sternberg cells of Hodgkin's disease consistently expressed MUM1. MUM1 was detected in normal and neoplastic activated T cells, and its expression usually paralleled that of CD30. These results suggest that MUM1 is involved in the late stages of B-cell differentiation and in T-cell activation and is deregulated in DLCL-B.

scholarly journals The T cell-B cell interaction via OX40-OX40L is necessary for the T cell-dependent humoral immune response.

1996 ◽  
Vol 183 (3) ◽  
pp. 979-989 ◽  
Author(s):  
E Stüber ◽  
W Strober
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Germinal Centers ◽  
Antibody Treatment ◽  
Activated T Cells ◽  
Activated B Cells

Recent in vitro studies have established that activated B cells express OX40 ligand (L), a member of the tumor necrosis factor/nerve growth factor family of cytokines, and become stimulated to proliferate and secrete immunoglobulin (Ig) after cross-linking of OX40L by its counterreceptor OX40, which is expressed on activated T cells. In the present study we investigated the in vivo role of this receptor-ligand pair for the interaction of T and B cells in the course of the T-dependent B cell response against 2,4,6 trinitro-phenyl-keyhole limpet hemocyanin. First, we showed that OX40 is maximally expressed by T cells in the periarteriolar lymphoid sheath (PALS) 3 d after primary immunization. These OX40+ cells are located in close proximity to antigen-specific, activated B cells. Second, we demonstrated that blocking of OX40-OX40L interaction with polyclonal anti-OX40 antibody or with antibodies against certain peptide sequences within its extracellular domain resulted in a profound decrease of the anti-hapten IgG response, whereas the antihapten IgM response was grossly unchanged. Third, we showed that this antibody treatment leads to an inhibition of the development of PALS-associated B cell foci, whereas the formation of germinal centers remained intact. Finally, our data suggest that, whereas B cell memory development was not impaired by anti-OX40 administration, OX40-OX40L interaction seems to be crucial in the secondary immune response. We conclude from these data that the OX40-OX40L interaction in vivo is necessary for the differentiation of activated B cells into highly Ig-producing cells, but is not involved in other pathways of antigen-driven B cell differentiation such as memory cell development in the germinal centers.

scholarly journals Activated T cells induce expression of B7/BB1 on normal or leukemic B cells through a CD40-dependent signal.

1993 ◽  
Vol 177 (4) ◽  
pp. 925-935 ◽  
Author(s):  
E A Ranheim ◽  
T J Kipps
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Cell Phenotype ◽  
Cell Contact ◽  
Activated T Cells ◽  
Antigen Presenting ◽  
Cell Cell

Cognate interactions between antigen-presenting B and T cells play crucial roles in immunologic responses. T cells that have been activated via the crosslinking of CD3 are able to induce B cell proliferation and immunoglobulin secretion in a major histocompatibility complex-unrestricted and contact-dependent manner. We find that such activated human CD4+ T cells, but not control Ig-treated T cells, may induce normal or leukemic B cells to express B7/BB1 and significantly higher levels of CD54 intercellular adhesion molecule 1 via a process that also requires direct cell-cell contact. To discern what cell surface molecule(s) may be responsible for signalling B cells to express B7/BB1, we added various monoclonal antibodies (mAbs) specific for T or B cell accessory molecules or control mAbs to cocultures of alpha-CD3-activated T cells and resting B cells. We find that only alpha-CD40 mAbs can significantly inhibit the increased expression of B7/BB1, suggesting that the ligand for CD40 expressed on activated T cells may be an important inducer of B7/BB1 expression. Subsequent experiments in fact demonstrate that alpha-CD40 mAbs, but not control mAbs, induce changes in B cell phenotype similar to those induced by activated T cells when the mAbs are presented on Fc gamma RII (CDw32)-expressing L cells. These phenotypic changes have significant effects on B cell function. Whereas chronic lymphocytic leukemia (CLL) B cells normally are very poor stimulators in allogeneic mixed lymphocyte reactions (MLRs), CLL-B cells preactivated via CD40 crosslinking are significantly better presenters of alloantigen, affecting up to 30-fold-greater stimulation of T cell proliferation than that induced by control treated or nontreated CLL-B cells. Similarly, the MLR of T cells stimulated by allogeneic nonleukemic B cells can be enhanced significantly if the stimulator B cells are preactivated via CD40 crosslinking. The enhanced MLR generated by such preactivated B cells may be inhibited by blocking B7/BB1-CD28 interaction with CTLA4Ig. These studies demonstrate a novel, CD40-dependent pathway for inducing B cell expression of B7/BB1 and enhancing B cell antigen-presenting cell activity that can be initiated via cell-cell contact with alpha-CD3-stimulated CD4+ T cells.

scholarly journals B cell-stimulatory factor 1 (BSF-1) promotes growth of helper T cell lines.

1986 ◽  
Vol 164 (2) ◽  
pp. 580-593 ◽  
Author(s):  
R Fernandez-Botran ◽  
P H Krammer ◽  
T Diamantstein ◽  
J W Uhr ◽  
E S Vitetta
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Activated T Cells ◽  
Growth Promoting ◽  
T Cell Lines ◽  
Stimulatory Factor

T cell-derived supernatants (SN) that contain B cell-stimulatory factor 1 (BSF-1) and lack IL-2 promote the growth of the IL-2-dependent T cell line, HT-2, as well as three other clones or lines of T cells that can provide help to B cells. The BSF-1 purified from these SNs promotes growth of HT-2 cells approximately 50% as effectively as purified IL-2. A potential involvement for contaminating IL-2 in the BSF-1 preparations was excluded by the demonstration that anti-BSF-1 mAbs blocked the BSF-1-induced growth of HT-2 cells; in contrast, these antibodies did not block the IL-2-induced proliferation of the HT-2 cells. In addition, anti-IL-2 mAbs or anti-IL-2-R antibodies blocked the HT-2 growth-promoting activity of purified IL-2, but not BSF-1. Finally, BSF-1 promoted only a very modest growth of Con A-induced T cell blasts, and failed to induce significant growth in seven other cytotoxic, alloreactive, and long-term T cell lines. Taken together, these results indicate that in addition to its known effects on resting and LPS-stimulated B cells, BSF-1 can promote growth of certain subsets of activated T cells, in particular, those that provide help to B cells.

scholarly journals The autoantigen-binding B cell repertoires of normal and of chronically graft-versus-host-diseased mice.

1987 ◽  
Vol 165 (6) ◽  
pp. 1675-1687 ◽  
Author(s):  
A G Rolink ◽  
T Radaszkiewicz ◽  
F Melchers
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
The Other ◽  
Cell Populations ◽  
Foreign Antigen ◽  
Alloreactive T Cells ◽  
Polyclonal Activator ◽  
Activated B Cells

A quantitative analysis of the frequencies of autoantibody-producing B cells in GVHD and in normal mice has been undertaken by generating collections of hybridomas of activated B cells. These hybridomas secreted sufficient quantities of Ig to allow binding analyses on a panel of autoantigens. B cells have been activated in a variety of ways. In vivo they were activated by injection of alloreactive T cells of one parent, leading to GVHD by a foreign antigen, sheep erythrocytes, in a secondary response, or by the polyclonal activator LPS. B cells from an experimentally unstimulated animal were used for an analysis of the normal background. In vitro B cells were activated by alloreactive T cells or by LPS. The frequencies of hybridomas and, therefore, of activated B cells producing autoantibodies to DNA or to kidney were not significantly different in mice activated by a graft-vs.-host T cell response as compared with B cell populations activated by any of the other procedures. They were found to compose 7.1-17.1% of the total repertoire of activated B cells. Moreover, the frequencies of autoantibody-producing activated B cells does not change with time after induction of the graft-vs.-host reaction. The pattern and frequencies of autoantigen-binding specificities to cytoskeleton, smooth muscle, nuclei, mitochondria, and DNA were not found to be different in any of the groups of hybridomas. The single notable exception, found in GVHD mice, were hybridomas producing autoantibodies to kidney proximal tubular brush border. These results allow the conclusion that autoantigen-binding B cells exist in an activated state in GVHD mice, as well as in mice activated by a foreign antigen or by a polyclonal activator, in B cell populations activated in vitro either by alloreactive T cells or by a polyclonal activator, and even in the background of experimentally unstimulated animals. T cell-mediated graft-vs.-host activation, in large part, does not lead to a selective expansion of autoantigen-binding B cells. The main difference between the graft-vs.-host-activated B cell repertoire and all others is that approximately 90% of teh autoantibodies were of the IgG class, whereas al autoantibodies found in the other groups were IgM.

scholarly journals Inhibition of normal B-cell function by human immunodeficiency virus envelope glycoprotein, gp120

Blood ◽  
1992 ◽  
Vol 79 (5) ◽  
pp. 1245-1254 ◽  
Author(s):  
N Chirmule ◽  
N Oyaizu ◽  
VS Kalyanaraman ◽  
S Pahwa
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Function ◽  
Cell Contact ◽  
Cell Proliferation And Differentiation ◽  
Cell Clones ◽  
Glycoprotein Gp120

Abstract Despite the occurrence of hypergammaglobulinemia in human immunodeficiency virus (HIV) infection, specific antibody production and in vitro B-cell differentiation responses are frequently impaired. In this study, we have examined the effects of HIV envelope glycoprotein gp120 on T-helper cell function for B cells. In the culture system used, B-cell functional responses were dependent on T-B- cell contact, since separation of T and B cells in double chambers by Transwell membranes rendered the B cells unresponsive in assays of antigen-induced B-cell proliferation and differentiation. Cytokines secreted by T cells were also essential, since anti-CD3 monoclonal antibody (mAb)-activated, paraformaldehyde-fixed T-cell clones failed to induce B-cell proliferation and differentiation. Pretreatment of the CD4+ antigen-specific T cells with gp120 was found to impair their ability to help autologous B cells, as determined by B-cell proliferation, polyclonal IgG secretion, and antigen-specific IgG secretion. The gp120-induced inhibition was specific in that it was blocked by soluble CD4. Furthermore, only fractionated small B cells (which are T-cell-dependent in their function) manifested impaired responses when cultured with gp120-treated T cells. Antigen-induced interleukin (IL)-2 and IL-4, but not IL-6, secretion were markedly reduced in gp120-treated T-cell clones. Addition of exogenous cytokines failed to compensate for defective helper function of gp120-treated T cells. The findings in this study indicate that gp120 impairs helper functions of CD4+ T cells by interfering with T-B-cell contact- dependent interaction; the inhibitory effects of soluble envelope proteins of HIV may contribute to the immunopathogenesis of the HIV- associated disease manifestations.

scholarly journals Activated CD4+CD25+ T cells selectively kill B lymphocytes

Blood ◽  
2006 ◽  
Vol 107 (10) ◽  
pp. 3925-3932 ◽  
Author(s):  
Dong-Mei Zhao ◽  
Angela M. Thornton ◽  
Richard J. DiPaolo ◽  
Ethan M. Shevach
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Cell Death ◽  
B Cells ◽  
B Cell ◽  
T Cell Activation ◽  
Fas Ligand ◽  
Cell Function ◽  
Cell Contact ◽  
Dependent Manner

The suppressive capacity of naturally occurring mouse CD4+CD25+ T cells on T-cell activation has been well documented. The present study is focused on the interaction of CD4+CD25+ T cells and B cells. By coculturing preactivated CD4+CD25+ T cells with B cells in the presence of polyclonal B-cell activators, we found that B-cell proliferation was significantly suppressed. The suppression of B-cell proliferation was due to increased cell death caused by the CD4+CD25+ T cells in a cell-contact–dependent manner. The induction of B-cell death is not mediated by Fas–Fas ligand pathway, but surprisingly, depends on the up-regulation of perforin and granzymes in the CD4+CD25+ T cells. Furthermore, activated CD4+CD25+ T cells preferentially killed antigen-presenting but not bystander B cells. Our results demonstrate that CD4+CD25+ T cells can act directly on B cells and suggest that the prevention of autoimmunity by CD4+CD25+ T cells can be explained, at least in part, by the direct regulation of B-cell function.

scholarly journals Defective interleukin-2 production and responsiveness by T cells in patients with chronic lymphocytic leukemia of B cell variety

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 279-284 ◽  
Author(s):  
O Ayanlar-Batuman ◽  
E Ebert ◽  
SP Hauptman
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Proliferative Response ◽  
Interleukin 2 ◽  
Lymphocytic Leukemia ◽  
T Cell Proliferation ◽  
Activated T Cells

Abstract The present studies were designed to investigate the mechanism(s) of the defective T cell proliferative response to various stimuli in patients with B cell chronic lymphocytic leukemia B-CLL. In 14 patients with advanced B-CLL (stage III or IV) we found the T cell response in the autologous (auto) and allogeneic (allo) mixed lymphocyte reaction (MLR) to be 35.7% and 30% of the controls, respectively. Proliferation in the MLR depends upon the production of and response to interleukin 2 (IL 2), a T cell growth factor. IL 2 production in eight B-CLL patients was 22% of the control. The response to IL 2 was measured by the increase in the T cell proliferation in the MLR with the addition of IL 2. T cell proliferation in both the auto and allo MLR of CLL patients was significantly lower than in the controls after the addition of IL 2. The proliferative response of normal T cells to stimulation by CLL B cells was 50% of the control. This latter response was increased to control levels when cultures were supplemented with exogenous IL 2, suggesting that CLL B cells could stimulate IL 2 receptor generation in normal T cells in an allo MLR, but not IL 2 production. The presence of IL 2 receptors on activated T cells was directly determined using anti- Tac, a monoclonal antibody with specificity for the IL 2 receptor. Of the mitogen- or MLR-activated T cells in CLL patients, 6% and 10%, respectively, expressed Tac antigen, whereas identically stimulated control T cells were 60% and 47% Tac+, respectively. Our findings suggest that T cells in B-CLL are defective in their recognition of self or foreign major histocompatibility antigens as demonstrated by their impaired responsiveness in the MLR. Thus, these cells are unable to produce IL 2 or generate IL 2 receptors.

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