201
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Boscá L, Díaz-Guerra MJ. Activation of protein kinase C from B lymphocytes by lipid A. Biochem Biophys Res Commun 1988; 152:149-54. [PMID: 3258743 DOI: 10.1016/s0006-291x(88)80692-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The effect of lipid A, a residue of the lipopolysaccharide molecule, on protein kinase C from B lymphocytes has been studied. Lipid A activates and promotes the translocation of protein kinase C from the soluble to the particulate membrane fraction in a cell-free system reconstituted with purified enzyme and membranes isolated from B lymphocytes. These results demonstrate that the activating effect of lipopolysaccharide on protein kinase C from B cells is due to the lipid moieties of this molecule.
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Affiliation(s)
- L Boscá
- Instituto de Bioquímica, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
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202
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Steele TA, Brahmi Z. Phosphatidylinositol metabolism accompanies early activation events in tumor target cell-stimulated human natural killer cells. Cell Immunol 1988; 112:402-13. [PMID: 2833358 DOI: 10.1016/0008-8749(88)90309-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This study examined the role of phospholipid metabolism in human natural killer (NK) cells upon activation by tumor target cells(TC). The effector cell (EC) population consisted of peripheral blood lymphocytes enriched for NK cells. Upon a 5-min exposure of EC to the NK-sensitive tumor TC K562 and U937, nearly four- and threefold increases in the incorporation of 32P into phosphatidylinositol (PI) occurred, respectively. In contrast, no increase in 32P incorporation into PI was seen when two NK-resistant TC were used. In addition, little or no change in the incorporation of 32P into phosphatidylcholine, phosphatidylethanolamine, or phosphatidylserine took place with any of the above TC. Depletion of Leu 11b-positive cells abolished the increase in 32P incorporation into PI when K562 were used in the phospholipid assay. Furthermore, labeling kinetics of this phospholipid turnover showed that it occurred less than 5 min following exposure to NK-sensitive TC and that phosphatidic acid, a breakdown product of phosphoinositides, was produced during this 5-min period. These results indicated that metabolism of a phosphoinositide took place and that it occurred in association with early activation events in NK cells. Quercetin and dibutyryladenosine-cyclic monophosphate (dbcAMP) plus theophylline exerted profound inhibitory effects on both NK activity and PI metabolism, suggesting a linkage between the two events. The inhibitors had no effect on target cell-binding capacity, indicating that the inhibition occurred postbinding. PI metabolism took place in the absence of extracellular calcium even though NK activity was completely abolished under the same conditions. Thus, we have shown PI metabolism, but not other phospholipids, to occur in human NK cells upon exposure to NK-sensitive TC, in association with early activation events. This event was independent of extracellular calcium and could be inhibited by quercetin or dbcAMP plus theophylline.
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Affiliation(s)
- T A Steele
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis 46223
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203
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Watanabe M, Watts TH, Gariepy J, Hozumi N. Function and behavior of surface immunoglobulin receptors in antigen-specific T cell-B cell interaction. Cell Immunol 1988; 112:226-35. [PMID: 2449980 DOI: 10.1016/0008-8749(88)90291-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The expression and function of surface immunoglobulin (sIg) receptors was analyzed using antigen-specific monoclonal B cells and T cells. When B cells were incubated with antigen (hapten carrier), hapten-specific sIg receptor expression was greatly reduced. The specific antigen-presentation activity of the B cells was also markedly reduced. Following the removal of antigen, expression of the sIg receptors was restored to original levels within 3-4 hr. Specific antigen-presentation activity of these B cells was concomitantly restored. Reduction of sIg receptor expression and specific antigen presentation were inhibited by the addition of competing free hapten, suggesting that crosslinking of sIg receptors is required for the observed changes in sIg receptor expression and that specific antigen presentation is hapten specific. Using oligopeptide-specific Th cells, we could show the requirement for processing of antigen in the interaction between hapten-specific B cells and carrier-specific T cells. These results indicated that the expression of sIg receptors for a specific antigen and the ability to present the antigen are interrelated.
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Affiliation(s)
- M Watanabe
- Mount Sinai Hospital Research Institute, Toronto, Ontario, Canada
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204
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Abbas AK. A reassessment of the mechanisms of antigen-specific T-cell-dependent B-cell activation. IMMUNOLOGY TODAY 1988; 9:89-94. [PMID: 3076764 DOI: 10.1016/0167-5699(88)91271-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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205
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Facci L, Skaper SD, Favaron M, Leon A. A role for gangliosides in astroglial cell differentiation in vitro. J Biophys Biochem Cytol 1988; 106:821-8. [PMID: 2831235 PMCID: PMC2115083 DOI: 10.1083/jcb.106.3.821] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Rat cerebral astroglial cells in culture display specific morphological and biochemical behaviors in response to exogenously added gangliosides. To examine a potential function for endogenous gangliosides in the processes of astroglial cell differentiation, we have used the B subunit of cholera toxin as a ganglioside-specific probe. The B subunit, which is multivalent and binds specifically to GM1 ganglioside on the cell surface, induced a classical star-shaped (stellate) morphology in the astroglial cells and inhibited DNA synthesis in a dose-dependent manner. The morphological response was massive and complete within 2 h, with an ED50 of 0.8 nM, and appeared to depend on the direct interaction of the B subunit with GM1 on the cell surface. A B subunit-evoked inhibition of DNA synthesis and cell division (ED50 = 0.2 nM) was observed when the cells were stimulated with defined mitogens, such as epidermal growth factor and basic fibroblast growth factor. Maximal inhibition approached 80% within 24 h. The effects of the B subunit were unrelated to increases in cAMP. These observations, taken together with previous studies, demonstrate that both endogenously occurring plasma membrane gangliosides and exogenously supplied gangliosides can influence the differentiative state (as judged by morphological and growth behaviors) of astroglial cells in vitro.
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Affiliation(s)
- L Facci
- Fidia Research Laboratories, Department of Central Nervous System Research, Abano Terme, Italy
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206
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Ledbetter JA, Rabinovitch PS, June CH, Song CW, Clark EA, Uckun FM. Antigen-independent regulation of cytoplasmic calcium in B cells with a 12-kDa B-cell growth factor and anti-CD19. Proc Natl Acad Sci U S A 1988; 85:1897-901. [PMID: 2450350 PMCID: PMC279888 DOI: 10.1073/pnas.85.6.1897] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Increases in cytoplasmic free calcium ([Ca2+]i) can be induced in resting B cells either by a low molecular weight (12-kDa) B-cell growth factor (LMW-BCGF) or by crosslinking the B-cell antigen CD19 with monoclonal antibody (mAb). LMW-BCGF causes a slow [Ca2+]i increase in peripheral blood and tonsillar B cells but has no effect on [Ca2+]i in resting T cells. B-cell [Ca2+]i responses mediated by anti-surface immunoglobulin (sIg) or anti-CD19 are potentiated by LMW-BCGF, but anti-sIg and anti-CD19 do not show additive [Ca2+]i responses. LMW-BCGF- and anti-CD19-induced [Ca2+]i signals are similar to the sIgM or sIgD-mediated signals in that they are inhibited by prior treatment with phorbol 12-myristate 13-acetate. However, LMW-BCGF- and CD19-mediated signals do not depend on the expression of sIg, since they were also observed on sIg-B-cell precursor acute lymphoblastic leukemia (ALL) cells. Both anti-CD19 and LMW-BCGF stimulated in vitro colony formation by ALL cells and showed additive effects when used together. [Ca2+]i responses to LMW-BCGF or CD19 cross-linking were also evident on certain pre-B-cell and lymphoma B-cell lines.
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207
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Owen CS. Phorbol ester (12-O-tetradecanoylphorbol 13-acetate) partially inhibits rapid intracellular free calcium transients triggered by anti-immunoglobulin in murine lymphocytes. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)69129-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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208
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MacDougall SL, Grinstein S, Gelfand EW. Activation of Ca2+-dependent K+ channels in human B lymphocytes by anti-immunoglobulin. J Clin Invest 1988; 81:449-54. [PMID: 2448342 PMCID: PMC329590 DOI: 10.1172/jci113340] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Many mammalian cell types exhibit Ca2+-dependent K+ channels, and activation of these channels by increasing intracellular calcium generally leads to a hyperpolarization of the plasma membrane. Their presence in B lymphocytes is as yet uncertain. Crosslinking Ig on the surface of B lymphocytes is known to increase the level of free cytoplasmic calcium ([Ca2+]i). However, rather than hyperpolarization, a depolarization has been reported to occur after treatment of B lymphocytes with anti-Ig. To determine if Ca2+-dependent K+ channels are present in B lymphocytes, and to examine the relationship between intracellular free calcium and membrane potential, we monitored [Ca2+]i by means of indo-1 and transmembrane potential using bis(1,3-diethylthiobarbituric)trimethine oxonol in human tonsillar B cells activated by anti-IgM. Treatment with anti-IgM induced a biphasic increase in [Ca2+]i and a simultaneous hyperpolarization. A similar hyperpolarization was induced by ionomycin, a Ca2+ ionophore. Delaying the development of the [Ca2+]i response by increasing the cytoplasmic Ca2+-buffering power delayed the hyperpolarization. Conversely, eliminating the sustained phase of the [Ca2+]i response by omission of external Ca2+ abolished the prolonged hyperpolarization. In fact, a sizable Na+-dependent depolarization was unmasked. This study demonstrates that in human B lymphocytes, Ca2+-dependent K+ channels can be activated by crosslinking of surface IgM. Moreover, it is likely that, by analogy with voltage-sensitive Ca2+ channels, Na+ can permeate through these ligand-gated Ca2+ "channels" in the absence of extracellular Ca2+.
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Affiliation(s)
- S L MacDougall
- Division of Immunology and Rheumatology, Hospital for Sick Children, Toronto, Ontario, Canada
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209
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Morelec MJ, Ensergueix D, Pedron T, Girard R, Chaby R. Opposite effects of lipopolysaccharide and dextran sulfate on membrane phospholipid metabolism of murine B lymphocytes. Eur J Immunol 1988; 18:301-7. [PMID: 2450758 DOI: 10.1002/eji.1830180219] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The metabolism of [3H]inositol- and [14C]arachidonate-labeled phospholipids of B lymphocytes from normal (C3H/HePAS) and endotoxin-hyporesponsive (C3H/HeJ) mice, after incubation with two B cell mitogens, lipopolysaccharide (LPS) and dextran sulfate (DxS) was examined. The early effects of the two mitogens on the biosynthesis of phosphoinositides were different. DxS enhanced the levels of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate in C3H/HeJ and C3H/HePAS cells, whereas LPS did not modify the levels of these components. When mixed with DxS, LPS reduced the effects of this stimulant. Analysis of the metabolism of fatty acids gave opposite results. Incorporation of arachidonate in all phospholipids, and particularly in phosphatidic acid, was inhibited in the two cell types after incubation with DxS, but was enhanced in C3H/HePAS and remained unchanged in C3H/HeJ cells after incubation with LPS. This activation of acyltransferases by LPS in B lymphocytes from endotoxin-responsive mice was inhibited when DxS was added in the stimulating mixture. The outcome of these opposite biochemical effects of LPS and DxS on the mitogenic responses of B cells was also examined. Preincubation with DxS for a 15-min period blocked the mitogenic effect of LPS in C3H/HePAS cells, whereas preincubation with LPS blocked the mitogenic effect of DxS in C3H/HeJ cells. Early changes in phospholipid metabolism induced by the two stimulants are therefore correlated with their late mitogenic effect.
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Affiliation(s)
- M J Morelec
- Unité de Biochimie des Antigènes, Institut Pasteur, Paris, France
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210
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Shearer WT, Gilliam EB, Rosenblatt HM, Orson FM. Anti-mu antibody stimulates the phosphatidylinositol cycle and immunoglobulin secretion in a human lymphoblastoid B-cell line, LA350. Cell Immunol 1988; 111:296-315. [PMID: 2827896 DOI: 10.1016/0008-8749(88)90095-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Within 5 min of the binding of anti-mu antibody (anti-mu) to surface IgM on LA350, a human lymphoblastoid B-cell line, there was a significantly enhanced incorporation of 32P into the phosphatidic acid (PA) and phosphatidylinositol (PI) fractions of cellular phospholipids and the magnitude of the early increase in PA was twice as great as that in PI. This anti-mu-enhanced incorporation of 32P into PA and PI required the binding of a divalent form of antibody (IgG or F(ab')2), was blocked by coincubation with micromolar concentrations of soluble IgM, was decreased by incubation of cells at temperatures lower than 37 degrees C, and was inhibited by coincubation with millimolar concentrations of dibutyryl cyclic AMP and theophylline. Similar incorporation studies with [3H]inositol demonstrated a selective and significant increase in labeling of PI. In LA350 labeled with [3H]inositol for 30 hr (equilibrium) and acutely stimulated by anti-mu, specific hydrolysis of phosphorylated PI (PI 4,5-bisphosphate) was measured by the significantly increased release at 15 min of radioactive inositol 1,4,5-trisphosphate, inositol 1,4 bisphosphate, and inositol 1-phosphate. The release of these inositol phosphates was significantly augmented by coincubation with 0.01 M LiCl which prevented their simultaneous enzymatic degradation. All of these findings are consistent with an activation of a linked series of metabolic events known as the PI cycle. In similar cell cultures anti-mu significantly stimulated the secretion of IgM by LA350 as measured at 48 hr in a reverse hemolytic plaque assay. Two other IgM-bearing human lymphoblastoid B-cell lines which gave no evidence of turnover of 32P in PA and PI in response to binding by anti-mu likewise failed to enhance their secretion of IgM. We conclude that the binding of surface IgM on LA350 by anti-mu results in the generation of a transmembrane signal which causes a rapid activation of the PI cycle which itself may play a role in the subsequent increase in IgM secretion.
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Affiliation(s)
- W T Shearer
- Department of Pediatrics, Baylor College of Medicine, Texas Childrens Hospital, Houston
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211
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Suchard SJ, Lo HK, Bourguignon LY. Isolation of Thy-1 caps and analysis of their phospholipid composition in mouse T-lymphoma cells. J Cell Physiol 1988; 134:67-77. [PMID: 2826503 DOI: 10.1002/jcp.1041340108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In this study we have used a density perturbation method to isolate anti-Thy-1 antibody-induced Thy-1 caps from mouse T-lymphoma cells in the absence of detergents, and then compared the phospholipid composition of these capped membranes with that of uncapped membranes. Initial phospholipid analysis by two-dimensional thin layer chromatography (2-D TLC) reveals a significant increase in the amount of 32P-labeled phosphatidylcholine in the Thy-1 capped membrane. In contrast, no significant changes are observed in the labeling of phosphatidylserine, phosphatidylethanolamine, or the sphingomyelins. Therefore, it is suggested that phosphatidylcholine may be involved in the organization and/or regulation of Thy-1 antigen redistribution. The composition of phosphoinositide in uncapped and capped membranes was analysed separately using one-dimensional thin layer chromatography (1-D TLC) to resolve phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PlP), and phosphatidylinositol 4, 5-bisphosphate (PIP2) from all other phospholipids. This analysis reveals a significant reduction in levels of PIP and PIP2, but not PI, in Thy-1 caps. Through the use of ion exchange column chromatography, we have found an increased production of all three species of inositol phosphates during anti-Thy-1 antibody-induced capping. Inositol 1, 4, 5-triphosphate (IP3) shows the most significant increase, compared to the much smaller increases in inositol 4, 5-bisphosphate (IP2) and inositol monophosphate (IP). These results suggest that the binding of anti-Thy-1 antibody to Thy-1 antigen activates phospholipase C which, in turn, initiates polyphosphoinositide turnover and IP3 production. It is proposed that these observed effects are the result of early signal transducing events which are prerequisite steps in Thy-1 receptor cap formation.
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Affiliation(s)
- S J Suchard
- Department of Anatomy and Cell Biology, University of Miami Medical School, Florida 33101
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212
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Germolec DR, Clark GC, Blank JA, Wiegand G, Luster MI. Biochemical events associated with inhibition of B-cell proliferation by phorbol diesters. INTERNATIONAL JOURNAL OF IMMUNOPHARMACOLOGY 1988; 10:953-65. [PMID: 3265131 DOI: 10.1016/0192-0561(88)90042-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Phorbol myristate acelate (PMA), a potent tumor promoter, has a variety of effects on cells of the immune system resulting in altered patterns of cell proliferation and differentiation. Although PMA is mitogenic or co-mitogenic for human lymphocytes and murine T-cells, it inhibits proliferation of murine B-cells stimulated by LPS or anti-Ig. PMA, however, does not inhibit the ability of LPS or anti-Ig to activate B-cells, as evidenced by increased Ia antigen expression and RNA synthesis. In the present studies it was shown that inhibition of DNA synthesis by PMA coincided with qualitative and quantitative changes in phosphorylated proteins. In particular, PMA treatment resulted in a unique profile of phosphoproteins independent of LPS or anti-Ig treatment. Inhibition of DNA synthesis occurred over a wide range of PMA concentrations. At concentrations up to 10(-9) M, inhibition of proliferation correlated with decreased phosphatidylinositol turnover and decreased intracellular Ca2+ levels, suggesting that PMA affects the phosphoinositide signal transduction pathway. However, at PMA concentrations less than 10(-10) M, inhibition of anti-Ig- and LPS-mediated proliferation occurred without inhibition of the phosphoinositide transduction signal. At these concentrations, PMA-induced inhibition of DNA synthesis was highly sensitive to recombinant IL-2. These data suggest that the antiproliferative effects of PMA on B-cells stimulated by LPS or anti-Ig may be mediated by two mechanisms. At high concentrations, PMA causes a feedback regulation of the phosphoinositide-dependent messenger system, while at lower concentrations, PMA alters the response to specific growth factors. Since PMA induces unique phosphoproteins and both of these events can be regulated by protein phosphorylation, it is possible that these unique phosphoproteins are responsible for the antiproliferative effects of PMA.
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Affiliation(s)
- D R Germolec
- Systemic Toxicology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
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213
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Dziarski R. Enhancement of B-cell stimulation by muramyl dipeptide through a mechanism not involving interleukin 1 or increased Ca2+ mobilization or protein kinase C activation. Cell Immunol 1988; 111:10-27. [PMID: 2448043 DOI: 10.1016/0008-8749(88)90047-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Muramyl dipeptide (MDP) enhanced mitogenic stimulation of mouse lymphocytes by polyclonal B cell activators (peptidoglycan, lipopolysaccharide, Staphylococcus aureus Cowan I cells, and pokeweed mitogen), but not by T-cell mitogens (phytohemagglutinin and concanavalin A). Only adjuvant-active MDP analogs were effective, whereas adjuvant-inactive MDP analogs, muramic acid, peptidoglycan pentapeptide, and low Mr digests of peptidoglycan were not. The half-maximal enhancement was seen at 5-10 microM MDP and occurred at both optimal and suboptimal concentrations of B cell mitogens. The enhancing effect of MDP was exerted on the B cells, since it was T cell- and macrophage-independent and was not mediated by IL-1. MDP was effective during the first 12 hrs of culture, and most strongly enhanced the mitogen-induced DNA synthesis, although significant enhancement of RNA synthesis and B cell differentiation into antibody-secreting cells was also observed. The enhancement of mitogenic response was not due to changed requirements for extracellular or intracellular Ca2+ or to increased activation of protein kinase C. These results demonstrate a novel immunoenhancing effect of MDP that should be useful in the studies on the mechanism of B cell activation.
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Affiliation(s)
- R Dziarski
- Department of Microbiology and Immunology, Northwest Center for Medical Education, Indiana University School of Medicine, Gary 46408
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214
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Mond JJ, Feuerstein N, Finkelman FD, Huang F, Huang KP, Dennis G. B-lymphocyte activation mediated by anti-immunoglobulin antibody in the absence of protein kinase C. Proc Natl Acad Sci U S A 1987; 84:8588-92. [PMID: 3500475 PMCID: PMC299590 DOI: 10.1073/pnas.84.23.8588] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
B-cell activation induced by crosslinking of surface immunoglobulin is known to stimulate hydrolysis of phosphatidylinositol to diacylglycerol and inositol trisphosphate. We now provide evidence that alternative pathways of activation may also be recruited during such activation. We utilized depletion of protein kinase C activity to determine whether this enzyme is required under all conditions for anti-immunoglobulin-stimulated B-cell activation. Although anti-immunoglobulin does not induce B-cell proliferation in protein kinase C-depleted cells, it stimulates an earlier event in B-cell activation as reflected by its ability to enhance the expression of major histocompatibility complex-encoded class II molecules. Furthermore, the ribonucleoside 8-mercaptoguanosine restores the ability of anti-immunoglobulin to induce B-cell proliferation in protein kinase C-depleted cells. This restoration is also demonstrated by an enhancement of synthesis of a nuclear protein that we find is increased during B-cell mitogenesis. These results indicate that B-cell activation stimulated by anti-immunoglobulin may recruit pathways in addition to the one dependent on protein kinase C.
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Affiliation(s)
- J J Mond
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
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215
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Roifman CM, Mills GB, Stewart D, Cheung RK, Grinstein S, Gelfand EW. Response of human B cells to different anti-immunoglobulin isotypes: absence of a correlation between early activation events and cell proliferation. Eur J Immunol 1987; 17:1737-42. [PMID: 3500860 DOI: 10.1002/eji.1830171209] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cross-linking of surface immunoglobulin (sIg) by antibodies against IgM, IgG and IgD activates B cells and in some circumstances can induce cell proliferation. We studied the potential link between anti-Ig-induced changes in the cytosolic free Ca2+ concentration ([Ca2+]i), inositol phosphate production and the ability to induce cell proliferation in the presence or absence of the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA). Anti-IgM, but not anti-IgD or anti-IgG, induced cell proliferation in the presence but not the absence of TPA. Each of the antibodies induced a rapid increase in [Ca2+]i which appeared to be due to release of Ca2+ from internal stores. This was followed by a sustained increase in [Ca2+]i, apparently due to Ca2+ uptake from the extracellular medium. Anti-IgD induced the greatest increase in [Ca2+]i, anti-IgM induced intermediate changes and anti-IgG the lowest change. Since inositol 1,3,5-trisphosphate (IP3) can release Ca2+ from internal stores, we tested the ability of each anti-Ig isotype to increase concentrations of IP3. In contrast to the change in [Ca2+]i and proliferation, anti-IgG induced the most significant increase in IP3 concentrations. Taken together these data indicate that changes in [Ca2+]i, inositol phosphate production and anti-Ig-induced human B cell proliferation are not directly linked. They also demonstrate that changes in [Ca2+]i, inositol phosphate production and activation of protein kinase C are not sufficient to induce proliferation of human B cells. It appears that anti-IgM induces an additional Ca2+-independent, inositol phosphate-independent and protein kinase C-independent activation signal which can collaborate with TPA to induce B cell proliferation. The molecular events involved in this signal remain to be identified.
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Affiliation(s)
- C M Roifman
- Division of Immunology/Rheumatology, Hospital for Sick Children, Toronto, Ontario, Canada
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216
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Högbom E, Mårtensson IL, Leanderson T. Regulation of immunoglobulin transcription rates and mRNA processing in proliferating normal B lymphocytes by activators of protein kinase C. Proc Natl Acad Sci U S A 1987; 84:9135-9. [PMID: 3122213 PMCID: PMC299707 DOI: 10.1073/pnas.84.24.9135] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Immunoglobulin gene expression in normal splenic B lymphocytes stimulated with lipopolysaccharide was selectively down-regulated by anti-IgM antibodies and a protein-kinase C-activating phorbol ester, phorbol 12,13-dibutyrate. This control was concomitant with a decreased rate of transcription of the IgM gene while "polymerase pausing" was induced in the IgD gene. The suppression was resistant to treatment with cycloheximide, indicating that it was not caused by a labile repressor protein. The down-regulation of immunoglobulin gene expression affected only the secretory form of immunoglobulin, while the mRNA levels for the membrane-bound form of immunoglobulin remained unaltered. We conclude that the mechanisms controlling immunoglobulin gene expression in untransformed B lymphocytes differ from those operating in tumors derived from the same cell lineage.
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Affiliation(s)
- E Högbom
- Department of Immunology, University of Uppsala Biomedical Center, Sweden
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217
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Wiener EC, Griffor MC, Scarpa A. Antibody-induced cAMP accumulation in splenocytes from athymic nude mice. FEBS Lett 1987; 224:33-7. [PMID: 2824242 DOI: 10.1016/0014-5793(87)80417-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Products from the hydrolysis of phosphatidylinositol 4,5-bisphosphate (IP3) can increase and/or potentiate cAMP accumulation in a variety of cells. Antibody to surface immunoglobulins activates IP3 hydrolysis in B-lymphocytes. In this study we have examined whether anti-Ig also stimulated and/or potentiated increases in the cAMP levels of splenocytes from athymic nude mice. Furthermore, since TPA potentiates anti-Ig-induced DNA synthesis and cAMP modulates DNA synthesis, the effects of TPA on any anti-Ig-induced changes in cAMP were also studied. Antibody (25 micrograms/ml) stimulated a rapid ris in cAMP which increased from 250 fmol/10(6) cells to 400 fmol/10(6) cells within 1 min and then subsided to 310 fmol/10(6) cells by 10 min. TPA (96 nM) suppressed the anti-Ig-induced cAMP accumulation at 1 min by 60%, but potentiated the forskolin (114 microM)-induced rise by 151%. Two other activators of protein kinase C, dioctanoylglycerol (5 microM), and anti-Ig (25 micrograms/ml), also potentiated the forskolin response by 198% and 52%, respectively. These results suggest that modulation of the adenylate cyclase system by anti-Ig may act in concert with cytokines and/or prostaglandins secreted by other lymphoid cells to define the state of proliferation or differentiation in B-cells.
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Affiliation(s)
- E C Wiener
- Case Western Reserve University, Department of Physiology and Biophysics, Cleveland, OH 44106
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218
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Valentine MA, Cotner T, Gaur L, Torres R, Clark EA. Expression of the human B-cell surface protein CD20: alteration by phorbol 12-myristate 13-acetate. Proc Natl Acad Sci U S A 1987; 84:8085-9. [PMID: 3500472 PMCID: PMC299482 DOI: 10.1073/pnas.84.22.8085] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The monoclonal antibody 1F5 recognizes human B-cell surface protein CD20 and can activate resting B cells; with this antibody we found CD20 to be a 35/37-kDa non-disulfide-linked protein. The protein has a pI of 7.5-8.0 and is phosphorylated in B-cell lines, tonsillar B cells, and peripheral blood B cells. Both CD20 surface expression and phosphorylation are increased on buoyant tonsillar B cells activated in vivo. Because phorbol 12-myristate 13-acetate (PMA) supports the activation signal initiated by monoclonal antibody 1F5, we studied the effect of PMA on CD20 expression. After brief incubation with mitogenic levels of PMA, the number of dense tonsillar B cells positive for CD20 protein transiently decreased. Paradoxically, the cells remaining positive had more surface CD20 than did control cells, and these remaining surface CD20 molecules were hyperphosphorylated. Furthermore, PMA not only induced phosphorylation of CD20 protein on Raji cells but also increased the internalization of CD20 molecules; both phosphorylation and internalization of CD20 molecules were decreased with the protein kinase C inhibitor palmitoyl carnitine. Conditions that increase CD20 phosphorylation are shown also to increase surface mobility of the molecule, suggesting that CD20 protein internalization may be a critical early event for B-cell entry into the G1 phase of the cell cycle.
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Affiliation(s)
- M A Valentine
- Department of Microbiology, University of Washington, Seattle 98195
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219
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Abstract
The 45Ca2+ uptake and 45Ca2+ release in saponin-permeabilized human lymphocytes were studied. An ATP-dependent Ca2+ uptake into a nonmitochondrial, intracellular Ca2+ store is observed which is approx. 2 orders of magnitude greater than the ATP-independent Ca2+ uptake. The Ca2+ uptake is inhibited by vanadate, but it is insensitive to oligomycin and ruthenium red. IP3 induces dose-dependent 45Ca2+ release. For half-maximum Ca2+ release 0.25-0.5 microM IP3 is required. The results of our studies suggest that 45Ca2+ is predominantly stored within the endoplasmic reticulum of the lymphocytes.
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Affiliation(s)
- G Eberl
- Institut für Physiologie, Universität Regensburg, FRG
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220
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Affiliation(s)
- E C Snow
- Department of Microbiology and Immunology, University of Kentucky Medical Center, Lexington 40536-0084
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221
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Zubler RH, Werner-Favre C, Wen L, Sekita K, Straub C. Theoretical and practical aspects of B-cell activation: murine and human systems. Immunol Rev 1987; 99:281-99. [PMID: 2960608 DOI: 10.1111/j.1600-065x.1987.tb01181.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have reviewed observations which were made during studies of murine and human B-cell responses in vitro. One currently faces difficulties in drawing any clear schema as to which external signals elicit which responses (activation, proliferation, differentiation) in B cells. However, the most potent antigen-dependent or polyclonal B-cell responses in vitro occur when, in addition to various cytokines, accessory cells, serum etc., the cultures contain either a) intact T-helper cells which enter into cell-to-cell contact with B cells, or b) some B-cell "mitogen" (T-independent antigen). Murine B cells activated with LPS and anti-Ig antibodies represent a model for the study of IL2 receptor expression and function. LPS does not act on human B cells. Certain mutant EL-4 thymoma cells are potent activators of murine and human B cells via a direct cell-to-cell interaction. The majority of human B cells can be induced to proliferate and generate a few hundred antibody-secreting cells each in the presence of such thymoma cells and a mixture of cytokines. From a practical point of view, this observation should be useful in a variety of investigations such as the analysis of the human B-cell specificity repertoire.
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Affiliation(s)
- R H Zubler
- Department of Medicine, Hôpital Cantonal Universitaire, Geneva, Switzerland
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222
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Scott DW, Chace JH, Warner GL, O'Garra A, Klaus GG, Quill H. Role of T cell-derived lymphokines in two models of B-cell tolerance. Immunol Rev 1987; 99:153-71. [PMID: 3315968 DOI: 10.1111/j.1600-065x.1987.tb01176.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- D W Scott
- Immunology Unit, University of Rochester Cancer Center, New York 14642
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223
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Klaus GG, Bijsterbosch MK, O'Garra A, Harnett MM, Rigley KP. Receptor signalling and crosstalk in B lymphocytes. Immunol Rev 1987; 99:19-38. [PMID: 2824341 DOI: 10.1111/j.1600-065x.1987.tb01170.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- G G Klaus
- Division of Immunology, National Institute for Medical Research, Mill Hill, London, U.K
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224
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O'Garra A, Rigley KP, Holman M, McLaughlin JB, Klaus GG. B-cell-stimulatory factor 1 reverses Fc receptor-mediated inhibition of B-lymphocyte activation. Proc Natl Acad Sci U S A 1987; 84:6254-8. [PMID: 3498163 PMCID: PMC299049 DOI: 10.1073/pnas.84.17.6254] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Intact (IgG class) rabbit anti-immunoglobulin antibodies are not mitogenic for mouse B cells but inhibit proliferation induced by F(ab')2 anti-Fab fragment antibodies (anti-Ig). In addition, cross-linkage of Fc and surface immunoglobulin receptors on B cells by intact anti-Ig inhibits inositol phospholipid breakdown (but not Ca2+ flux) resulting from ligation of antigen receptors. This system, therefore, provides a polyclonal model for B-cell inactivation by antigen-antibody complexes. T-cell-derived B-cell-stimulatory factor 1 acts synergistically with submitogenic concentrations of F(ab')2 anti-Ig to induce B-cell proliferation. We show here that B-cell-stimulatory factor 1 and intact anti-Ig also induce B cells to synthesize DNA. However, B-cell-stimulatory factor 1 does not induce inositol phospholipid breakdown, does not mobilize Ca2+ in B cells, nor does it influence the magnitude of these responses provoked by intact anti-Ig.
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225
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Abstract
Calcium is an important factor in the immune response. Extracellular calcium is required for antibody production by B lymphocytes. Several investigators have demonstrated that crosslinking of receptors on B lymphocytes by anti-mu antibody induces an increase in intracellular calcium. There are few data on the role of intracellular calcium mobilization or calcium influx in tolerance induction in B cells. We studied changes in free intracellular calcium concentration ([Ca+2]i) induced by exposure of dinitrophenyl (DNP)-specific B cells to the tolerance-inducing conjugate DNP-murine IgG2a (DNP-MGG). Splenic B cells enriched for DNP-specific cells and DNP-specific continuous B-cell lines were used for the studies. Exposure of B cells to the tolerogen DNP-MGG, the antigen DNP-keyhole limpet hemocyanin (DNP-KLH), or the antigen DNP-Ficoll induced an increase in free [Ca+2]i which was due to both mobilization of Ca+2 from endoplasmic reticulum (ER) and influx of extracellular Ca+2. This increase was DNP specific since no significant change was seen with carriers alone and no change was seen in cells that were not DNP specific. The DNP-MGG and DNP-Ficoll induced the same amount of Ca+2 release from ER but the release induced by DNP-KLH was higher. When B cells, which were made tolerant by in vitro incubation with DNP-MGG, were incubated with antigens, a mobilization of Ca+2 from endoplasmic reticulum occurred that was the same as that of nontolerant B cells. Since Ca+2 mobilization is associated with Ig receptor-dependent early B-cell activation, it is likely that the tolerant B cell can still receive an activation signal through the Ig receptors.
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226
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Dugas B, Calenda A, Delfraissy JF, Vazquez A, Bach JF, Galanaud P. The cytosolic free calcium in anti-mu-stimulated human B cells is derived partly from extracellular medium and partly from intracellular stores. Eur J Immunol 1987; 17:1323-8. [PMID: 2820750 DOI: 10.1002/eji.1830170916] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The inositol phospholipid metabolism and the increase in cytosolic free Ca2+ concentration ([Ca2+]i) into the cell are recognized as two important events in the anti-mu-induced B cell activation. The anti-mu stimulation caused the [3H]inositol incorporation and also a rapid increase in [Ca2+]i from 85 nM to 285 nM. This signal returned to baseline a few minutes after stimulation. By using the fluorescent indicator quin-2 we demonstrated that this [Ca2+]i uptake was derived part from extracellular medium and part from intracellular stores. Both EGTA (a calcium chelator) and TMB.8 (a drug which interferes with Ca2+ sequestration by smooth endoplasmic reticulum) partially suppressed the intracellular Ca2+ uptake and were fully inhibitory when added together. The role of Ca2+ from intracellular stores may also be evidenced in calcium-free experiments, or in permeabilized experiments using exogenous inositol 1,4,5-trisphosphate (IP3, the putative mobilizer of intracellular Ca2+). Preventing the increase in [Ca2+]i also prevents the apparition of early activation makers. These results are consistent with the hypothesis that the Ca2+ increase in B cells stimulated by anti-mu is caused by the generation of IP3 during the phosphatidyl-inositol metabolism and also by the entry of extracellular Ca2+ through the plasma membrane.
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Affiliation(s)
- B Dugas
- Departement des Biotechnologies, Roussel-UCLAF, Romainville, France
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227
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Wickremasinghe RG, Mire-Sluis AR, Hoffbrand AV. Interleukin-2 binding to activated human T lymphocytes triggers generation of cyclic AMP but not of inositol phosphates. FEBS Lett 1987; 220:52-6. [PMID: 3038615 DOI: 10.1016/0014-5793(87)80874-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Human T lymphocytes stimulated with phytohaemagglutinin undergo a single round of cell division. Further proliferation is dependent on the lymphokine interleukin-2 (IL2) [(1987) Immunology 60, 7-12]. We show here that binding of IL2 to its receptors on the lymphocyte surface triggers the generation of cyclic AMP. In contrast, generation of inositol phosphates from the breakdown of inositol lipids was not detected. We suggest that cyclic AMP may play a role in the transduction of the IL2 proliferative signal in T lymphocytes.
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228
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Paul WE, Brown M, Hornbeck P, Mizuguchi J, Ohara J, Rabin E, Snapper C, Tsang W. Regulation of B-lymphocyte activation, proliferation, and differentiation. Ann N Y Acad Sci 1987; 505:82-9. [PMID: 2825578 DOI: 10.1111/j.1749-6632.1987.tb51284.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- W E Paul
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
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229
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Feuerstein N, Mond JJ. “Numatrin,” a nuclear matrix protein associated with induction of proliferation in B lymphocytes. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)60972-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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230
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Wilson HA, Greenblatt D, Poenie M, Finkelman FD, Tsien RY. Crosslinkage of B lymphocyte surface immunoglobulin by anti-Ig or antigen induces prolonged oscillation of intracellular ionized calcium. J Exp Med 1987; 166:601-6. [PMID: 3496421 PMCID: PMC2189588 DOI: 10.1084/jem.166.2.601] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Our results indicate that B lymphocytes stimulated with anti-Ig or antigen exhibit repetitive [Ca2+]i transients which persist for hours. The magnitude of these transients favors an important and ongoing role for [Ca2+]i elevation in antigen driven B cell activation. Repetitive Ca2+ transients may prove to be a prevalent mechanism of Ca2+ signaling. In preliminary experiments (with L. E. Samelson and R. D. Klausner), we have observed Ca2+ transients in cloned T cells stimulated with antigen. Woods et al. have described repetitive free Ca2+ transients in hepatocytes stimulated with extracellular ligands promoting glycogenolysis, and suggest that the intervals of base-line [Ca2+]i levels explain the absence of mitochondrial overload in chronically stimulated cells. These considerations apply equally to B lymphocytes and recommend caution in delineating the range of Ca2+-mediated functions by prolonged coculture of cells with Ca2+ ionophores. Our experiments were done in a simple recording chamber with one cell type. No cell interactions were observed. Given the variety of indicator dyes now available, the technical approach we present, augmented by a more sophisticated recording chamber, is a potentially powerful tool for examining the intrinsic, and T- or accessory cell-dependent, physiology of B cell differentiation.
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231
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Klaus GG. Cyclosporin as a probe for different modes of lymphocyte activation. ANNALES DE L'INSTITUT PASTEUR. IMMUNOLOGY 1987; 138:626-8. [PMID: 3499915 DOI: 10.1016/s0769-2625(87)80135-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- G G Klaus
- Division of Immunology, National Institute for Medical Research, Mill Hill, London
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232
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Abstract
In this paper we describe the posttranslational processing of the p63/LMP (latent membrane protein) encoded by Epstein-Barr virus in transformed B cells. Specifically, we show that after synthesis, free LMP disappeared with a half-life of about 0.5 h. This was caused by the association of LMP with an insoluble complex. All detectable LMP in the plasma membrane was insoluble. This interaction was resistant to nondenaturing detergents but readily dissociated with 8 M urea or by boiling in 0.5% sodium dodecyl sulfate, suggesting that LMP may be associated with cytoskeletal elements. Most of the Nonidet P-40-insoluble LMP was phosphorylated (ppLMP) primarily on serine but also on threonine residues. No phosphotyrosine was detected. Furthermore, greater than 90% of the ppLMP resided in the Nonidet P-40-insoluble fraction, suggesting a strong correlation between complexing and phosphorylation. Additionally, ppLMP was found to be associated with a 53,000-molecular-weight phosphoprotein (pp53) of unknown origin. Finally, LMP turned over extremely rapidly, with a half-life of about 2 h. Taken together, these properties suggest that although LMP falls broadly within the category of phosphorylated, cytoskeleton-associated oncoproteins, it is nevertheless clearly different from any previously described member of this family.
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233
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Chused TM, Wilson HA, Greenblatt D, Ishida Y, Edison LJ, Tsien RY, Finkelman FD. Flow cytometric analysis of murine splenic B lymphocyte cytosolic free calcium response to anti-IgM and anti-IgD. CYTOMETRY 1987; 8:396-404. [PMID: 3497786 DOI: 10.1002/cyto.990080409] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The accurate measurement of ionized intracellular calcium [Ca++]i in single cells by flow cytometry with the use of a new fluorescent calcium chelator, indo-1, is described. We have developed a dependable in situ calibration technique that indicates a resting [Ca++]i in lymphocytes of 100 nM. The enhanced fluorescence of this probe permits its use at sufficiently low cytoplasmic concentrations that buffering of [Ca++]i transients does not occur. The [Ca++]i response of small resting B lymphocytes to crosslinking of surface antigen receptors by anti-immunoglobulin is heterogeneous. With maximal stimulus, the peak [Ca++]i response occurs in 10 to 20 seconds with most cells reaching levels greater than/1 microM. Mean [Ca++]i falls to between 300 and 800 nM by 100 seconds where it remains for more than 10 min. Anti-delta is a more potent stimulus of increased [Ca++]i than anti-mu in terms of both [Ca++]i level and fraction of B cells responding. Whether this is due to the greater density of surface IgD than IgM, a difference in signal transduction efficiency, or both, is not yet known. Surface immunoglobulin receptors are present in great excess. Less than 3% of surface immunoglobulin is crosslinked at the peak of the [Ca++]i response.
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234
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Carter HR, Smith AD. Resolution of the phosphoinositide-specific phospholipase C isolated from porcine lymphocytes into multiple species. Partial purification of two isoenzymes. Biochem J 1987; 244:639-45. [PMID: 2833219 PMCID: PMC1148044 DOI: 10.1042/bj2440639] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Phospholipase C isolated from porcine mesenteric lymph node lymphocytes was distributed between the soluble and particulate fractions. Enzyme activity was found predominantly in the soluble fraction with optimal activity at pH 5.5. Gel filtration chromatography of the soluble phospholipase C revealed that it was composed of multiple species of enzyme activity. The activity associated with the particulate fraction had optimal activity at pH 7.0, as also did one of the species of soluble phospholipase C. Cellulose phosphate chromatography resolved the major soluble form into two species designated PLC-A and PLC-B. Both phenyl-Sepharose chromatography and hydroxyapatite chromatography purified these species still further. PLC-A and PLC-B demonstrated similar activities against phosphatidylinositol with a pH optimum near 5.5. The phospholipase C activities were abolished against this substrate by the addition of 1 mM-EDTA. When assayed in the presence of Ca2+-EDTA buffers providing a range of Ca2+ free concentrations, both enzymes exhibited optimal activity near 10(-3) M free Ca2+, but PLC-B was inhibited above this concentration more than PLC-A. PLC-B exhibited markedly lower activity against phosphatidylinositol 4,5-bisphosphate, suspended as liposomes of the pure phospholipid, than did PLC-A.
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Affiliation(s)
- H R Carter
- Department of Chemical Pathology, Middlesex Hospital Medical School, London, U.K
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235
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Gorelick MH, Bishop GA, Haughton G, Pisetsky DS. Cyclosporine inhibition of CH series murine B-cell lymphomas. Cell Immunol 1987; 107:219-26. [PMID: 3495347 DOI: 10.1016/0008-8749(87)90281-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To investigate the mechanisms by which cyclosporine (CsA) inhibits B-cell function, the effect of this agent on murine B-lymphoma cell lines of the CH series was tested. These lymphomas appear to be derived from a restricted B-cell population on the basis of their common expression of the Ly-1 cell surface marker and autoantibody products. Proliferation of each of the six cell lines tested was inhibited by CsA at doses without effect on the nonlymphoid HeLa cell line. The cell lines, however, differed from each other in their sensitivity to this agent. To correlate this sensitivity to other functional B-cell properties, the effect of lipopolysaccharide (LPS) on the proliferation of the CH cell lines was tested. Three of the lines showed enhanced proliferation to LPS; two were inhibited while one was unaffected. The cell lines that responded with increased proliferation to LPS were the most sensitive to CsA. These results indicate that sensitivity to CsA may be a common property of B cells of certain lineages, although the degree of sensitivity may be influenced by the activation properties of these cells.
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236
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Kramer CM, Johnson KW, Dooley RK, Holsapple MP. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) enhances antibody production and protein kinase activity in murine B cells. Biochem Biophys Res Commun 1987; 145:25-33. [PMID: 3496088 DOI: 10.1016/0006-291x(87)91282-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Treatment of murine spleen cells with 30 nM TCDD resulted in an approximately 3 fold increase in unstimulated antibody production after 3 days in culture. This response was not accompanied by increased cellular proliferation and may represent an effect of TCDD on B cell activation or differentiation. Since PMA is capable of activating B cells, presumably via PKC, we have compared the effects of PMA and TCDD on protein kinase activation and phosphorylation of endogenous proteins in a highly purified preparation of B cells. In contrast to a reduction of cytosolic PKC activity, the expected effect of PMA, TCDD caused an increase in basal kinase activity with no effect on PKC activity. Addition of either PMA or TCDD resulted in enhanced phosphorylation of a similar profile of proteins, including proteins of Mr 12.2, 14.6, 29.2, 52.3 and 62.7 KDa. Addition of TCDD also resulted in the increased phosphorylation of a protein of Mr 45.2, which was unaffected by PMA. Combined treatment with PMA and TCDD resulted in additive responses. The additive effects of PMA and TCDD suggest an interaction at the level of protein phosphorylation which is mediated by different kinases. Therefore, TCDD may be stimulating B cells via an early effect on an unidentified protein kinase.
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237
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Wiener E, Lebman D, Cebra J, Scarpa A. Initiation of DNA synthesis in murine B cells is independent of early changes in the cytosolic free calcium. Arch Biochem Biophys 1987; 254:462-71. [PMID: 2437858 DOI: 10.1016/0003-9861(87)90125-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The relationship between changes in the intracellular free Ca2+ concentration, [Ca2+]i, and the initiation of proliferation of murine B cells after the addition of mitogens and activators was studied. The effects of lipopolysaccharide (LPS), 12-O-tetradecanoyl phorbol-13-acetate (TPA), rabbit IgG antimouse Fab (IgG RAM Fab), and its F(ab')2 fragment (F(ab')2 anti-Fab) on the [Ca2+]i were measured using the fluorescent calcium indicator Fura-2. In parallel experiments, DNA and/or RNA synthesis were measured by assaying [3H]thymidine and/or [3H]uridine uptake. LPS stimulated a 20-120 X increase in the [3H]thymidine uptake, and a 3-7 X increase in [3H]uridine uptake without inducing any change in the [Ca2+]i. TPA induced a marginal increase in [3H]thymidine and [3H]uridine uptake, without effecting any change in the [Ca2+]i. In contrast, low doses of IgG RAM Fab produced a triphasic change in the [Ca2+]i, but had no effect on the [3H]thymidine or [3H]uridine uptake, even at much higher concentrations. Similarly, low doses of the F(ab')2 fragment induced sizable increases in the [Ca2+]i without affecting the [3H]nucleoside uptake. However, higher concentrations of F(ab')2 anti Fab increased the [3H]thymidine uptake and [3H]uridine uptake, while also increasing the [Ca2+]i. Significantly, pretreating the cells with TPA for 3 min virtually abolished the [Ca2+]i increase induced by IgG RAM Fab while simultaneously potentiating an increase in the IgG RAM Fab-induced [3H]thymidine uptake 85-fold. In the presence of TPA, IgG RAM Fab also induced a 2- to 30-fold increase in [3H]uridine uptake. Similarly, TPA virtually abolished the [Ca2+]i increase induced by the F(ab')2 anti-Fab fragment, yet it stimulated a F(ab')2 anti-Fab-induced uptake of [3H]thymidine and [3H]uridine by 120 and 10 times, respectively.
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238
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Cambier JC, Chen ZZ, Ransom JT, Coggeshall KM, Klemsz MJ, Harris LK, Sandoval VM, Newell MK. Differential transmembrane signaling in B lymphocyte activation. Ann N Y Acad Sci 1987; 494:52-64. [PMID: 3037967 DOI: 10.1111/j.1749-6632.1987.tb29481.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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239
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240
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Choquet D, Sarthou P, Primi D, Cazenave PA, Korn H. Cyclic AMP-modulated potassium channels in murine B cells and their precursors. Science 1987; 235:1211-4. [PMID: 2434998 DOI: 10.1126/science.2434998] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A voltage-dependent potassium current (the delayed rectifier) has been found in murine B cells and their precursors with the whole-cell patch-clamp technique. The type of channel involved in the generation of this current appears to be present throughout all stages of pre-B-cell differentiation, since it is detected in pre-B cell lines infected with Abelson murine leukemia virus; these cell lines represent various phases of B-cell development. Thus, the presence of this channel is not obviously correlated with B-cell differentiation. Although blocked by Co2+, the channel, or channels, does not appear to be activated by Ca2+ entry. It is, however, inactivated by high intracellular Ca2+ concentrations. In addition, elevation of intracellular adenosine 3', 5'-monophosphate induces at all potentials a rapid decrease in the peak potassium conductance and increased rates of activation and inactivation. Therefore, potassium channels can be physiologically modulated by second messengers in lymphocytes.
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241
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Shenker BJ, Matt WC. Suppression of human lymphocyte responsiveness by forskolin: reversal by 12-O-tetradecanoyl phorbol 13-acetate, diacylglycerol and ionomycin. IMMUNOPHARMACOLOGY 1987; 13:73-86. [PMID: 3032853 DOI: 10.1016/0162-3109(87)90028-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Forskolin, a potent activator of adenylate cyclase, was examined for its ability to alter human peripheral blood lymphocyte (HPBL) activation by both mitogens and antigens. We found that forskolin, at concentrations ranging from 0.04 to 25 micrograms/ml, caused a dose-dependent inhibition of HPBL responses to mitogens (concanavalin A, phytohemagglutinin, pokeweed mitogen and Staphylococcus aureus) and to recall antigens (tetanus toxoid and streptokinase/streptodornase). Inhibition was reflected in altered DNA, RNA and protein synthesis, including immunoglobulin production, and was not due to altered cell viability. Forskolin also induced a 19-fold increase in HPBL cyclic AMP levels at the same concentrations that suppressed HPBL function. To further define the mechanism(s) by which these elevations in cyclic AMP suppressed HPBL function, we tried to reverse these inhibitory effects with several agents; ascorbic acid, carbachol and levamisole had no effect. However, the phorbol ester, 12-O-tetradecanoyl phorbol 13-acetate, as well as L-alpha-1,2-dioleoyl diacylglycerol were able to completely reverse the inhibition. Furthermore, the Ca2+ ionophore, ionomycin, was also able to act synergistically with lower and less effective concentrations of 12-O-tetradecanoyl phorbol 13-acetate to reverse the inhibitory effects of forskolin. The data suggest that forskolin-induced elevations in cyclic AMP may lead to inhibition (or, more correctly, prevents the activation) of protein kinase C, presumably by inhibiting phospholipid turnover. Our studies suggest a linkage between these two opposing membrane-signal transduction systems with protein kinase C representing a pivotal point for various regulatory signals that ultimately control lymphocyte activation and function.
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242
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DeFranco AL, Gold MR, Jakway JP. B-lymphocyte signal transduction in response to anti-immunoglobulin and bacterial lipopolysaccharide. Immunol Rev 1987; 95:161-76. [PMID: 3032773 DOI: 10.1111/j.1600-065x.1987.tb00504.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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243
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Abraham R, Ho S, Barna T, McKean D. Transmembrane signaling during interleukin 1-dependent T cell activation. Interactions of signal 1- and signal 2-type mediators with the phosphoinositide-dependent signal transduction mechanism. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)61566-2] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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244
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DeFranco AL. Transmembrane signaling reactions generated in B cells in response to anti-IgM or lipopolysaccharide. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1987; 213:189-93. [PMID: 3498297 DOI: 10.1007/978-1-4684-5323-2_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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245
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Paul WE, Mizuguchi J, Beaven MA, Hornbeck P, Tsang W, Ohara J. B lymphocyte activation. The roles of receptor cross-linkage and BSF-1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1987; 213:207-14. [PMID: 3498299 DOI: 10.1007/978-1-4684-5323-2_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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246
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Schimpl A, Chen-Bettecken U, Wecker E. Regulation of Ig gene expression in murine B-lymphocytes. HAEMATOLOGY AND BLOOD TRANSFUSION 1987; 31:332-6. [PMID: 3502112 DOI: 10.1007/978-3-642-72624-8_69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- A Schimpl
- Institut für Virologie und Immunobiologie, Universität Würzburg
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247
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Bijsterbosch MK, Klaus GG. Tumor-promoting phorbol esters suppress receptor-stimulated inositol phospholipid degradation and Ca2+ mobilization in mouse lymphocytes. Eur J Immunol 1987; 17:113-8. [PMID: 3028820 DOI: 10.1002/eji.1830170119] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Anti-immunoglobulin antibodies (anti-Ig) provoke the rapid breakdown of phosphatidylinositol bisphosphate (PIP2), elevation of cytoplasmic Ca2+ levels ([Ca2+]i) and activation of protein kinase C (PKC) in B lymphocytes. Tumor-promoting phorbol esters, like phorbol myristate acetate, also activate PKC, but inhibit anti-Ig-induced B cell proliferation. To investigate the basis of the latter effect, we studied the influence of phorbol esters on PIP2 degradation and [Ca2+]i in murine B cells. The results show that PKC-activating phorbol esters cause marked inhibition of anti-Ig-stimulated PIP2 breakdown and Ca2+ mobilization. In addition, these agents inhibit concanavalin A-provoked Ca2+ influx, lower resting cytoplasmic Ca2+ levels and reduce ionophore-induced Ca2+ influx in B cells. Apparently, PKC stimulation causes feedback inhibition of receptor signalling, not only by suppressing PIP2 degradation, but also by exerting additional complex effects on the control of [Ca2+]i in B cells. It is, however, not clear how these findings relate to the anti-proliferative effects of phorbol esters on B cells.
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MESH Headings
- Animals
- Antibodies, Anti-Idiotypic/immunology
- B-Lymphocytes/drug effects
- B-Lymphocytes/metabolism
- Calcimycin/pharmacology
- Calcium/metabolism
- Depression, Chemical
- Male
- Mice
- Mice, Inbred C57BL/immunology
- Mice, Inbred CBA/immunology
- Phorbol Esters/pharmacology
- Phosphatidylinositol 4,5-Diphosphate
- Phosphatidylinositols/metabolism
- Protein Kinase C/metabolism
- Receptors, Antigen, B-Cell/analysis
- Receptors, Antigen, B-Cell/drug effects
- Receptors, Antigen, B-Cell/physiology
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248
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Ashwell JD, Cunningham RE, Noguchi PD, Hernandez D. Cell growth cycle block of T cell hybridomas upon activation with antigen. J Exp Med 1987; 165:173-94. [PMID: 3491868 PMCID: PMC2188264 DOI: 10.1084/jem.165.1.173] [Citation(s) in RCA: 202] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Stimulation of antigen-specific T cell hybridomas with the appropriate antigen/MHC combination, at concentrations that resulted in the secretion of the lymphokine interleukin 2, resulted in a dose-dependent decrease in both [3H]thymidine incorporation and cell growth. Flow cytometric studies demonstrated that stimulation with antigen resulted in a cell cycle block that was most evident at the G1/S border, and mixing studies revealed that bystander T cells of different antigen specificities were not affected. For at least the large majority of T cells, the G1/S cell cycle block appeared to be irreversible after 24 h of exposure to antigen. This cell cycle block may be useful as a rapid and quantitative measure of T cell hybridoma activation, as a means of selecting T cell hybridomas that have functional alterations in the reception of stimulatory signals, and may serve as a model of the induction of tolerance in immature T cells.
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Cambier JC, Ransom JT, Harris LK, Coggeshall KM, Chen ZZ, Newell MK, Justement LB. Coupling of B cell surface Ig, Ia and BSF1 receptors to intracellular "second messengers". ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1987; 213:195-205. [PMID: 2820209 DOI: 10.1007/978-1-4684-5323-2_19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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250
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