X-linked severe combined immunodeficiency with gamma delta T cells

A patient with X-linked severe combined immunodeficiency (X-SCID) was found to have a deletion mutation of a four base pair in the transmembrane domain of the IL-2 receptor gamma chain gene, a subunit shared by the receptors for IL-4, IL-7, IL-9, and IL-15 (common gamma chain; gamma c). He had very few alpha beta T cells but had a considerable number of gamma delta T cells in his peripheral blood. Fluorescence in situ hybridization (FISH) analysis showed that the gamma delta T cells in his peripheral blood were not of maternal origin. He had received a Bacillus Calmette-Guerin (BCG) vaccination before recognition of the disease, and the BCG infection remained quiescent with no reaction for 19 months. After successful bone marrow transplantation, the site of the BCG vaccination showed a reaction, and live BCG were detected. It is useful to consider the relationship between the existence of gamma delta T cells and BCG in this case, and it is suggested that gamma delta T cells may be, in a given situation, less dependent on the gamma c chain than are alpha beta T cells.

Negative signaling in B cells by surface immunoglobulins

Cross-linking of surface immunoglobulins generates negative signals that cause B-cell death unless appropriate rescue signals are provided. Surface IgM is the main transducer of the negative signaling, but surface IgD and IgG may also transduce negative signaling when cross-linked intensively. In the surface IgM+, IgD+ human malignant B lymphoma cell lines B104 and DND-39, cross-linking of surface IgM by anti-IgM antibodies induced cell death. Anti-IgM antibody-induced B104 cell death was inhibited by stimulation with alpha- and beta-interferons but not stimulation with anti-CD40 antibody or IL-4, whereas anti-IgM antibody-induced DND-39 cell death was inhibited by stimulation with anti-CD40 antibody but not stimulation with alpha- and beta-interferons. Anti-IgM antibody-stimulated B104 cells had morphologic features compatible with necrosis, whereas anti-IgM antibody-stimulated DND-39 cells showed morphologic features of apoptosis. CD11a/CD54-dependent cell adhesion induced by stimulation with anti-CD40 antibody was involved in anti-CD40 antibody-mediated inhibition of anti-IgM antibody-induced DND-39 cells. In normal human mature B cells, cross-linking of surface IgM induced different signaling consequences, including DNA synthesis or cell division (positive signaling) or cell cycle arrest or death (negative signaling). In this system, too, CD40-transduced signal inhibited anti-IgM antibody-induced negative signaling, and CD11a/CD54-dependent cell adhesion played a role in the rescue process. It is suggested that quantitatively different intensities of surface IgM cross-linking induce qualitatively different signaling consequences; relatively weak cross-linking may induce DNA synthesis; moderate cross-linking may induce DNA synthesis with cell cycle arrest at the G2/M interphase; and intense cross-linking may induce apoptotic cell death. The reasons for this difference are not yet known. Further elucidation of the molecular mechanisms responsible for surface IgM-mediated negative signaling and its rescue signaling may contribute toward development of therapy for allergic disorders by artificial modulation of specific immunoglobulin production.

Signal transduction pathway of interleukin-4 and interleukin-13 in human B cells derived from X-linked severe combined immunodeficiency patients

Interleukin-4 (IL-4) and IL-13 are functionally similar cytokines. The functional IL-4 receptor (IL-4R) consists of the IL-4R alpha chain (IL-4R alpha) and the IL-2R gamma chain (gamma c), which is shared by the IL-2, IL-7, IL-9, and IL-15 receptors. The functional IL-13R is thought to involve the IL-4R alpha but not gamma c. In this study, we have analyzed activation of members of the Janus tyrosine kinase (Jak) family and signal transducers and activators of transcription (STAT) 6 induced by IL-4 and IL-13 in Epstein-Barr virus-transformed B cells derived from two patients of X-linked severe combined immunodeficiency, who have mutations of the gamma c gene in the extracellular and intracellular domains. In these B cells, IL-4 failed to induce tyrosine phosphorylation of Jak3 and activation of STAT6, or activation of these molecules was significantly decreased compared with Epstein-Barr virus-transformed normal B cells. In contrast, IL-13 activated STAT6 in these cells as well as normal B cells. However, Jak3 was not activated by IL-13, even in normal B cells. These results clearly indicated that gamma c is essential for activation of Jak3 and STAT6 in the signal transduction pathway of IL-4 in human B cells and that IL-13 does not utilize gamma c but activates STAT6 through an alternative pathway, which is not impaired in B cells of X-linked severe combined immunodeficiency patients.

Role of LFA-1/ICAM-1-dependent cell adhesion in CD40-mediated inhibition of anti-IgM antibody-induced B-cell death

Cross-linking of surface IgM by anti-IgM antibody caused activation-induced cell death of a surface IgM+, IgD+ human B lymphoma cell line, B104. The dying B104 cells did not show the morphology of apoptosis but did show that of necrosis. However, anti-IgM antibody caused apoptosis of another surface IgM+, IgD+ human B lymphoma cell line, DND-39. The influx of extracellular Ca2+ was necessary for the cell deaths of B104 and DND-39 caused by anti-IgM antibody. Their cell deaths were inhibited by cyclosporine. The anti-IgM antibody-induced cell death of DND-39, but not that of B104, was prevented by costimulation with anti-CD40 antibody. In human peripheral blood B-cells, anti-IgM antibody inhibited cell cycle transition induced by Staphylococcus aureus Cowan I at the G2/M interphase without inhibition of DNA synthesis. In this system, too, anti-CD40 antibody canceled the inhibitory signal transduced through surface IgM and increased the number of M phase cells. Blocking antibodies against the leukocyte function-associated antigen-I/intercellular adhesion molecule-1 system decreased the rescue effect of anti-CD40 antibody in both DND-39 cells and peripheral B-cells, which shows that leukocyte function-associated antigen-1/intercellular adhesion molecule-1-dependent cell adhesion plays an important role in the CD40-mediated inhibition of surface IgM-mediated negative signals.

Pyrrolidine dithiocarbamate inhibits intercellular adhesion molecule-1 biosynthesis induced by cytokines in human fibroblasts

Intercellular adhesion molecule-1 (ICAM-1), the ligand of lymphocyte function-associated antigen-1, plays an important role in the interactions of a variety of hemopoietic and nonhemopoietic cells, including leukocytes, fibroblasts, and endothelial cells. ICAM-1 is known to be involved in the onset of several diseases such as inflammation, allograft rejection, and so on. In this report, we investigated the effects of dexamethasone, cyclosporin A, FK506, and pyrrolidine dithiocarbamate (PDTC) on the induction of the ICAM-1 gene by cytokines in fibroblasts. PDTC, a potent inhibitor of NF-kappa B, was shown by ELISA and FACS analysis to prevent dramatically the expression of the ICAM-1 gene stimulated by IL-1 alpha, IFN-gamma, and PMA, although the other reagents inhibited it only slightly. Ribonuclease protection assay revealed that PDTC blocked the expression of the ICAM-1 gene at the mRNA level. To elucidate the mechanism of this inhibition, we constructed a series of ICAM-1 promoter deletion mutants linked to the chloramphenicol acetyl transferase gene and analyzed the effect of PDTC on their activities. Transient transfection analysis indicated that the critical region for inhibition by PDTC is an NF-kappa B binding site-like motif (GGGAGGATTCC, ICAM-1 kappa B) that is located at position-540. Electrophoresis mobility shift assay revealed that PDTC actually inhibits the binding of NF-kappa B (or NF-kappa B-like) protein to the ICAM-1 kappa B site. These findings suggest that PDTC inhibits ICAM-1 gene expression by inhibiting the association of NF-kappa B (or NF-kappa B-like) protein with the ICAM-1 kappa B site.

Pyrrolidine dithiocarbamate inhibits intercellular adhesion molecule-1 biosynthesis induced by cytokines in human fibroblasts

Intercellular adhesion molecule-1 (ICAM-1), the ligand of lymphocyte function-associated antigen-1, plays an important role in the interactions of a variety of hemopoietic and nonhemopoietic cells, including leukocytes, fibroblasts, and endothelial cells. ICAM-1 is known to be involved in the onset of several diseases such as inflammation, allograft rejection, and so on. In this report, we investigated the effects of dexamethasone, cyclosporin A, FK506, and pyrrolidine dithiocarbamate (PDTC) on the induction of the ICAM-1 gene by cytokines in fibroblasts. PDTC, a potent inhibitor of NF-kappa B, was shown by ELISA and FACS analysis to prevent dramatically the expression of the ICAM-1 gene stimulated by IL-1 alpha, IFN-gamma, and PMA, although the other reagents inhibited it only slightly. Ribonuclease protection assay revealed that PDTC blocked the expression of the ICAM-1 gene at the mRNA level. To elucidate the mechanism of this inhibition, we constructed a series of ICAM-1 promoter deletion mutants linked to the chloramphenicol acetyl transferase gene and analyzed the effect of PDTC on their activities. Transient transfection analysis indicated that the critical region for inhibition by PDTC is an NF-kappa B binding site-like motif (GGGAGGATTCC, ICAM-1 kappa B) that is located at position-540. Electrophoresis mobility shift assay revealed that PDTC actually inhibits the binding of NF-kappa B (or NF-kappa B-like) protein to the ICAM-1 kappa B site. These findings suggest that PDTC inhibits ICAM-1 gene expression by inhibiting the association of NF-kappa B (or NF-kappa B-like) protein with the ICAM-1 kappa B site.

Cis-acting DNA elements of mouse granulocyte-macrophage colony-stimulating factor gene responsive to Fc epsilon receptor cross-linking stimulation in the mouse mast cell line MC/9

Mouse mast cells produce many kinds of cytokines in response to cross-linking of high affinity Fc epsilon receptor (Fc epsilon RI). Among these cytokines, granulocyte-macrophage CSF (GM-CSF) gene induction in mouse mast cells has been reported to be regulated at both the transcriptional level and the post-transcriptional level. We analyzed the mechanism of the transcriptional regulation of GM-CSF gene induction through Fc epsilon RI cross-linking stimulation in the mouse mast cell line MC/9. In MC/9, the GM-CSF gene was activated transcriptionally by Fc epsilon RI cross-linking stimulation. The 5' deletion analysis of GM-CSF gene promoter indicated that the 5' boundary of the responsive promoter region lay between positions -113 and -95. When the deletion was extended to positions -72 or -60, the stimulatory effect was significantly diminished. We then examined 3' deletion of pmGMCAT -113 from position -60. This analysis indicated that the 3' boundary lay between positions -84 and -72. No subfragments of the region spanning positions -113 to -72 could cover the full induction level. A site-directed mutagenesis experiment revealed that the sequence spanning positions -108 to -72 was needed for full activation. These data indicate that GM-CSF gene in mast cells is activated mainly through the sequence spanning positions -108 to -72.

Cis-acting DNA elements of mouse granulocyte-macrophage colony-stimulating factor gene responsive to Fc epsilon receptor cross-linking stimulation in the mouse mast cell line MC/9

Mouse mast cells produce many kinds of cytokines in response to cross-linking of high affinity Fc epsilon receptor (Fc epsilon RI). Among these cytokines, granulocyte-macrophage CSF (GM-CSF) gene induction in mouse mast cells has been reported to be regulated at both the transcriptional level and the post-transcriptional level. We analyzed the mechanism of the transcriptional regulation of GM-CSF gene induction through Fc epsilon RI cross-linking stimulation in the mouse mast cell line MC/9. In MC/9, the GM-CSF gene was activated transcriptionally by Fc epsilon RI cross-linking stimulation. The 5' deletion analysis of GM-CSF gene promoter indicated that the 5' boundary of the responsive promoter region lay between positions -113 and -95. When the deletion was extended to positions -72 or -60, the stimulatory effect was significantly diminished. We then examined 3' deletion of pmGMCAT -113 from position -60. This analysis indicated that the 3' boundary lay between positions -84 and -72. No subfragments of the region spanning positions -113 to -72 could cover the full induction level. A site-directed mutagenesis experiment revealed that the sequence spanning positions -108 to -72 was needed for full activation. These data indicate that GM-CSF gene in mast cells is activated mainly through the sequence spanning positions -108 to -72.

IgM-mediated B cell apoptosis

Cross-linking of surface immunoglobulin M (sIgM) on normal mature B cells induces different signaling consequences, including DNA synthesis (positive signaling) and cell cycle arrest and/or death by apoptosis (negative signaling). Presumably, the difference depends on the intensity of sIgM cross-linking: relatively weak cross-linking induces DNA synthesis, moderate cross-linking induces DNA synthesis with cell cycle arrest at the G2/M interphase, and intense cross-linking induces apoptosis. In vivo experiments with transgenic mice have shown that relatively weak cross-linking of sIgM by soluble antigens induces anergy in autoreactive B cells, whereas intense sIgM cross-linking by membrane-bound forms of antigens induces deletion of them. However, it is still unknown whether the different intensities of sIgM cross-linking generate qualitatively different signals responsible for DNA synthesis or cell death or whether they generate qualitatively the same but quantitatively different signals, and the quantitative difference is responsible for the induction of positive or negative signaling. The sIgM-mediated negative signaling presumably plays an important role in the induction and maintenance of B cell tolerance, and sIgD and sIgG also possess the machinery necessary for negative signaling. Negative signaling through sIgM is dependent on tyrosine kinase(s) and Ca2+ influx and is sensitive to cyclosporin A in certain types of B cells but not in all B cells. It has been suggested that there are different intracellular signaling pathways that transduce negative signaling via sIgM, and that activation-induced B cell death by sIgM cross-linking does not necessarily show DNA fragmentation and the morphology of apoptosis. On the other hand, sIgM-mediated B cell death may be inhibited in the presence of appropriate co-stimulators such as IL-4, alpha-, and beta-interferons and CD40-mediated signaling. The CD40-mediated signaling effectively inhibits sIgM-mediated B cell apoptosis in many but not all experimental systems. Although homotypic cell adhesion through the LFA-1/ICAM-1 dependent pathway was shown to be involved in certain types of CD40-mediated inhibition of sIgM-mediated negative signaling, it is still not known how the cytokines and CD40-mediated signaling inhibit sIgM-mediated B cell death. The molecular mechanisms responsible for sIgM-mediated negative signaling and for the inhibitory signaling against sIgM-mediated negative signaling need further elucidation.

Developmental changes of GM-CSF gene inducibility in embryonal carcinoma cells

Murine embryonal carcinoma (EC) P19 cells, a tissue culture model of early embryonic development, failed to produce cytokines, such as interleukin-3 (IL-3), IL-4, granulocytemacrophage colony stimulating factor (GM-CSF) and interferon-beta (IFN-beta) at the mRNA level. Differentiation induced by retinoic acid (RA) released this repression to produce some cytokines. GM-CSF and IFN-beta genes were expressed in response to PMA/A23187, poly(I):poly(C), IL-1 alpha, forskolin, or LPS stimulation in differentiated P19 cells, whereas IL-3 and IL-4 genes were not expressed. To elucidate the mechanism of the GM-CSF gene induction after differentiation, we transfected a series of 5' deletion mutants of the mouse GM-CSF promoter fused to the bacterial CAT gene. The 740-bp fragment of the 5'-flanking region mediated the positive response. Deletion analysis revealed that the 5' boundary region of the DNA element required for activation lies between positions -95 and -84 and the region upstream of position -95 appears inhibitory. These results indicate that the maturation of the transcriptional machinery after differentiation results in the activation of the GM-CSF gene.

Involvement of LFA-1/intracellular adhesion molecule-1-dependent cell adhesion in CD40-mediated inhibition of human B lymphoma cell death induced by surface IgM crosslinking

B cells have been shown to receive negative signals for their growth through crosslinking of surface IgM (sIgM), and it has been demonstrated that anti-IgM Abs induce B cell death. Proliferation of B cells in response to Ag stimulation in vivo may thus require additional signals that inhibit the sIgM-transduced negative signals. Signaling through CD40 has been proposed as a candidate for such costimulatory signals. To investigate the role of CD40-transduced signals in sIgM-mediated B cell death, we used a human B cell line (DND-39) that expresses sIgM, sIgD, and CD40. Crosslinking of sIgM, but not sIgD, by Abs induced DND-39 cell death. The dying cells showed the morphology of apoptosis and DNA fragmentation. Anti-CD40 Abs induced homotypic adhesion of DND-39 cells and rescued them from anti-IgM Ab-induced cell death. Anti-CD40 Abs inhibited anti-IgM Ab-induced cell death when added within 3 h after stimulation with anti-IgM Ab. Treatment with Abs against CD11a, CD18, or CD54 inhibited not only the homotypic adhesion but also the inhibition of anti-IgM Ab-induced apoptosis by anti-CD40 Ab. CD11a antisense decreased the surface CD11a expression, the anti-CD40 Ab-induced homotypic adhesion, and the inhibitory effect of anti-CD40 Ab on anti-IgM Ab-induced apoptosis. The data show that LFA-1/ICAM-1-dependent cell adhesion induced by signaling through CD40 plays an important role in the inhibition of anti-IgM Ab-induced apoptosis of DND-39 cells.

Involvement of LFA-1/intracellular adhesion molecule-1-dependent cell adhesion in CD40-mediated inhibition of human B lymphoma cell death induced by surface IgM crosslinking

B cells have been shown to receive negative signals for their growth through crosslinking of surface IgM (sIgM), and it has been demonstrated that anti-IgM Abs induce B cell death. Proliferation of B cells in response to Ag stimulation in vivo may thus require additional signals that inhibit the sIgM-transduced negative signals. Signaling through CD40 has been proposed as a candidate for such costimulatory signals. To investigate the role of CD40-transduced signals in sIgM-mediated B cell death, we used a human B cell line (DND-39) that expresses sIgM, sIgD, and CD40. Crosslinking of sIgM, but not sIgD, by Abs induced DND-39 cell death. The dying cells showed the morphology of apoptosis and DNA fragmentation. Anti-CD40 Abs induced homotypic adhesion of DND-39 cells and rescued them from anti-IgM Ab-induced cell death. Anti-CD40 Abs inhibited anti-IgM Ab-induced cell death when added within 3 h after stimulation with anti-IgM Ab. Treatment with Abs against CD11a, CD18, or CD54 inhibited not only the homotypic adhesion but also the inhibition of anti-IgM Ab-induced apoptosis by anti-CD40 Ab. CD11a antisense decreased the surface CD11a expression, the anti-CD40 Ab-induced homotypic adhesion, and the inhibitory effect of anti-CD40 Ab on anti-IgM Ab-induced apoptosis. The data show that LFA-1/ICAM-1-dependent cell adhesion induced by signaling through CD40 plays an important role in the inhibition of anti-IgM Ab-induced apoptosis of DND-39 cells.

Positive and negative signals transduced through surface immunoglobulins in human B cells

Cross-linking of surface IgM and surface IgD by anti-IgM antibodies and anti-IgD antibodies, respectively, showed different effects on the growth of normal human peripheral blood B cells and the human B lymphoma cell line, B104. Only cross-linking of surface IgM transduced signals that inhibited cell division of peripheral blood B cells and B104 cells at the G2/M interphase. In B104 cells, the inhibition of cell division was followed by rapid B104 cell death. The negative signals were inhibited by cyclosporin A and FK-506 at lower concentrations than those that inhibited proliferation of the B cells. Anti-IgM antibody-induced B104 cell death was dependent on Ca2+ influx and macromolecular synthesis. B104 cells treated with anti-IgM antibodies showed neither DNA fragmentation or morphology of apoptosis but showed DNA single-strand breaks and morphology of necrosis. Nicotinamide inhibited anti-IgM antibody-induced B104 cell death and the involvement of poly(adenosine diphosphate-ribosyl)ation was suggested in the process of the B104 cell death. With regard to the intracellular mechanisms responsible for the different signals, however, no qualitative difference was detected in putative signal transducers, including tyrosine phosphorylated protein, phosphatidyl inositol turnover, Ca2+ influx, activation of protein kinase C, and messenger ribonucleic acid expression of c-fos and Egr-1 when surface IgM and surface IgD were crosslinked. Further investigations of the mechanisms responsible for the different signals transduced through surface IgM and surface IgD will provide better understanding of immunodeficiencies and autoimmune diseases.

Effects of cyclic AMP on expression of LFA-1, Mac-1, and VLA-4 and eosinophilic differentiation of a human leukemia cell line, EoL-1

We examined the effect of dibutyryl cAMP (dbcAMP) on the expression of LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18), and VLA-4 (CD49/CD29) and on eosinophilic differentiation of a human leukemia cell line, EoL-1. Dibutyryl cAMP induced eosinophilic differentiation of EoL-1 cells from 6-9 days after the start of culture with down-regulation of CD11a, CD18, and CD49 expression and up-regulation of CD11b expression. Changes in integrin expression, except for CD18, were seen predominantly in the fraction containing eosinophilic granule-positive cells, suggesting that the changes were dependent on eosinophilic differentiation. On the other hand, dbcAMP-induced changes of integrin expression were reversible and were not seen on day 9 when dbcAMP was removed on day 3, whereas eosinophilic differentiation was still present. A combination of G-CSF and TNF-alpha, which also induced eosinophilic differentiation of EoL-1 cells, increased CD11b expression slightly but had no significant effect on the expression of the other integrins. Butyrate and PMA up-regulated CD11b expression without eosinophilic differentiation. The results collectively suggest that the regulation of integrin expression on EoL-1 cells is partly dependent and partly not dependent on eosinophilic differentiation. The possible involvement of protein kinase A and protein kinase C in these changes is suggested.

Mechanisms involved in the inhibition of growth of a human B lymphoma cell line, B104, by anti-MHC class II antibodies

The mechanisms involved in the inhibition of growth of a human B lymphoma cell line, B104, by anti-MHC class II antibodies (Ab) were compared with those in anti-IgM Ab-induced B104 growth inhibition. Two anti-MHC class II Ab, L227 and 2.06, inhibited the growth of B104 cells, although 2.06, but not L227, needed to be further cross-linked with a goat anti-mouse IgG Ab (GAM) to show the effect. L227 induced an increase in intracellular free Ca2+ concentration ([Ca2+]i) from the intracellular pool and little or no protein tyrosine phosphorylation, phosphatidyl inositol turnover, or expression of Egr-1 mRNA, whereas 2.06 plus GAM induced an increase in [Ca2+]i from both the intracellular and, in particular, the extracellular pools. The inhibition of B104 cell growth induced by anti-MHC class II Ab was Ca(2+)-independent and not inhibited by actinomycin D or cyclosporin A, and cell cycle arrest at the G2/M interphase was not observed. These features are very different from those observed in B104 cell death induced by anti-IgM Ab. Neither DNA fragmentation nor the morphology of apoptosis was observed. These findings demonstrate that cross-linking of MHC class II molecules transduced the negative signals through intracellular mechanisms different from those present in the cross-linking of surface IgM.

Induction of eosinophilic granules, nonspecific esterase activity and CD14 expression in the human eosinophilic leukemia cell line, EOL-1

We examined the expression of eosinophilic granules, esterase activity and CD14 in a human eosinophilic cell line, EoL-1. Unstimulated EoL-1 cells were weakly positive for nonspecific esterase, but negative for surface CD14, and contained a few eosinophilic granule-positive cells. A combination of G-CSF and TNF-alpha increased the eosinophilic granule-containing cells, but failed to increase esterase activity or CD14 expression. IFN-gamma alone or in combination with TNF-alpha enhanced nonspecific esterase activity but failed to induce CD14 expression or increase eosinophilic granule-containing cells. dbcAMP increased eosinophilic granule-containing cells, nonspecific esterase activity and CD14 expression. Specific esterase activity was not detected in any circumstances. EoL-1 cells fractionated by density gradients or CD14 expression showed nonspecific esterase activity and CD14 expression in both the eosinophilic granule-positive and negative cell populations. Forskolin and butyrate had a synergistic effect on CD14 induction and protein kinase A was suggested to play a role in dbcAMP-induced CD14 expression. A protein kinase C activator, phorbol 12-myristate 13-acetate, did not increase eosinophilic granules, nonspecific esterase activity or CD14 expression in EoL-1 cells. The results show that EoL-1 cells can express nonspecific esterase and CD14, but the expression is not necessarily restricted to cells which have differentiated into the monocyte/macrophage lineage.

Molecular basis for developmental changes of GM-CSF gene inducibility in embryonal carcinoma cells

In a previous report, we reported that the induction of GM-CSF gene in differentiated P19 cells results from the maturation of the transcriptional machinery. Here, we identified a cis-DNA element which confers the activation of GM-CSF gene in response to PMA/A23187 stimulation in differentiated state. Analysis of the 5'-flanking region between -113 and -60 revealed two elements responsible for promotion and one for inhibition, and the overall effects led to the activation of GM-CSF gene mainly through the sequence between -95 and -73. Using the oligonucleotide between -94 and -73 as a probe in gel retardation assays, we identified a DNA-binding protein, NF-GM-P19, the binding activity of which was induced after differentiation in response to PMA/A23187 stimulation. These results indicate that the induction of GM-CSF gene after differentiation results from the maturation of the transcriptional machinery which recognizes the sequence between -95 and -73.

Induction of phosphatidylinositol turnover and EGR-1 mRNA expression by crosslinking of surface IgM and IgD in the human B cell line B104

We have previously shown that a human B lymphoma cell line, B104, expressed surface IgM (sIgM) and surface IgD (sIgD), and that crosslinking of sIgM and sIgD by anti-IgM antibody (Ab) and anti-IgD Ab, respectively, induced Ca2+ influx to almost the same degree, whereas only sIgM-crosslinking caused B104 cell death. Here, we investigated the accumulation of cyclic AMP (cAMP), the hydrolysis of inositol phosphates, protein kinase C (PKC) activity and the induction of Egr-1 and c-fos mRNA expression by sIgM- and sIgD-crosslinking to examine differences in the signals mediated through sIgM and sIgD in B104 cells. Both sIgM- and sIgD-crosslinking with antibodies induced elevation of cAMP levels, phosphatidylinositol turnover, PKC activation and expression of Egr-1 and c-fos mRNA, although sIgM-crosslinking was more effective than sIgD-crosslinking, presumably due to the higher expression of sIgM than of sIgD. Egr-1 mRNA expression induced by sIgM- and sIgD-crosslinking was inhibited by H7, erbstatin and genistein, but not by HA1004. Erbstatin and genistein inhibited the sIg-crosslinking-induced Egr-1 mRNA expression in a dose-dependent manner parallel to that observed in the inhibition of sIg-crosslinking-induced protein tyrosine phosphorylation. Phorbol myristate acetate induced Egr-1 mRNA expression but forskolin and dibutyryl cyclic AMP did not. These findings suggest that the Egr-1 mRNA activating signals through sIgM and sIgD are protein tyrosine kinase- and PKC-dependent, but protein kinase A-independent. Cyclosporin A (CsA) and FK506 rescued B104 cells from death induced by anti-IgM Ab, but did not affect the expression of Egr-1 and c-fos mRNA, showing that CsA and FK506 affect signal transducers differently from or downstream to these molecules. The difference in signals transduced through sIgM and sIgD in B104 cells is discussed.

Anti-Fas antibody induces different types of cell death in the human histiocytic cell line, U937, and the human B cell line, B104: the role of single-strand DNA breaks and poly (ADP-ribosyl)ation in cell death

We investigated the anti-Fas antibody-induced cell death in two different types of human cell lines, U937 and B104. IFN-gamma increased the surface expression of Fas antigen and susceptibility to anti-Fas Ab-induced cell death of B104 and U937 cells. Anti-Fas Ab-induced death of U937 and B104 cells required neither a Ca2+ influx nor macromolecular synthesis. U937 cells treated with anti-Fas Ab represented apoptosis with DNA fragmentation, whereas anti-Fas Ab-treated B104 cells did not. Single-strand DNA breaks, however, appeared in the B104 cells. Zinc ions prevented DNA fragmentation and the morphological features of apoptosis in anti-Fas Ab-treated U937 cells, but did not inhibit cell death. However, zinc ions, when used in combination with the poly(ADP-ribosyl)ation inhibitors, inhibited anti-Fas Ab-induced U937 cell death. The inhibitors by themselves did not inhibit anti-Fas Ab-induced U937 cell death, but did inhibit anti-Fas Ab-induced B104 cell death. A substantial decrease in NAD pools was observed in anti-Fas Ab-treated B104 and U937 cells in parallel with the increase of DNA strand breaks before cell death became apparent. These results suggest the involvement of single-strand DNA breaks and poly(ADP-ribosyl)ation in the mechanisms of anti-Fas Ab-induced U937 and B104 cell death.

Induction of phosphatidylinositol-linked Fc gamma receptor III expression on an eosinophilic cell line, EoL-1, by dibutyryl cyclic AMP and interferon-gamma

The expression of Fc gamma receptor III (Fc gamma RIII) on a human eosinophilic leukemia cell line, EoL-1, was examined and compared with its expression on normal blood eosinophils. Surface Fc gamma RIII expression on EoL-1 cells could be induced in vitro with a combination of dibutyryl cAMP (dbcAMP) and gamma-interferon (IFN-gamma), but not with IFN-gamma or dbcAMP alone. Pretreatment of EoL-1 cells with dbcAMP induced EoL-1 cells to express Fc gamma RIII when stimulated with IFN-gamma, but EoL-1 cells pretreated with IFN-gamma and then stimulated with dbcAMP failed to express Fc gamma RIII. Cyclic AMP was shown to play a role in the effect of dbcAMP. Both the treatment with phosphatidyl-inositol-specific phospholipase C (PI-PLC) and the restriction enzyme digestion of Fc gamma RIII cDNA showed that the Fc gamma RIII on EoL-1 cells was a phosphatidylinositol-linked form. On the other hand, freshly isolated blood eosinophils constitutively expressed few, if any, Fc gamma RIII, and IFN-gamma induced Fc gamma RIII expression on them in vitro. Dibutyryl cAMP did not induce Fc gamma RIII expression and even suppressed the IFN-gamma-induced Fc gamma RIII expression on normal eosinophils. The EoL-1 cell line appears to be a useful in vitro model for the expression and function of the phosphatidylinositol-linked form of Fc gamma RIII on eosinophils.

Tyrosine phosphorylation of IgM- and IgD-associated molecules of a human B lymphoma cell line B104

We investigated tyrosine phosphorylation and structural properties of the IgM-associated molecules in comparison with IgD-associated molecules in a recently established human surface IgM+, IgD+ B lymphoma cell line, B104, the growth of which was irreversibly inhibited by anti-IgM mAbs but not by anti-IgD mAbs. Tyrosine kinase activity and tyrosine phosphorylated proteins were detected in anti-IgM and anti-IgD immunoprecipitates from digitonin lysates of B104 cells with the use of an in vitro kinase assay followed by a re-immunoprecipitation experiment with anti-phosphotyrosine mAbs. Tyrosine phosphorylated proteins of 74, 58-44, 41, and 39 kDa were detected in anti-IgM immunoprecipitates, whereas tyrosine phosphorylated proteins of 74, 58-44, and 39 kDa, but not 41 kDa, were detected in anti-IgD immunoprecipitates. Crosslinking of surface IgM and surface IgD stimulated rapid tyrosine phosphorylation of different sets of proteins which included tyrosine-phosphorylated proteins of the same or similar molecular weights as those detected in the anti-IgM and anti-IgD immunoprecipitates respectively. After deglycosylation by N-glycosidase, both the IgM- and IgD-associated phosphoproteins (pp58-pp39) gave rise to the same three bands of 29, 27, and 26 kDa. Proteolytic peptide mapping of these three deglycosylated proteins showed that the primary structures of the IgM- and IgD-associated molecules are identical, suggesting that the IgM- and IgD-associated phosphoproteins (pp58-pp39) are the products of the same or closely related genes. One of the products, pp41, may be associated with IgM, but not with IgD, although the same gene product may be associated with IgD in a different glycosylation pattern.

Anti-IgM antibody-induced cell death in a human B lymphoma cell line, B104, represents a novel programmed cell death

We investigated the mechanisms of anti-IgM antibody-induced cell death in a recently established human surface IgM+ IgD+ B lymphoma cell line, B104, the growth of which is irreversibly inhibited by anti-IgM antibody but not by anti-IgD antibody, and compared it with the cell death of T cells via TCR/CD3 complex and with the cell death of a murine anti-IgM antibody-sensitive B lymphoma cell line, WEHI-231. The rapid time course of B104 cell death and its requirements for de novo macromolecular synthesis and Ca2+ influx suggest that anti-IgM antibody-induced B104 cell death is an active Ca(2+)-dependent programmed cell death. Moreover, cyclosporin A rescued B104 cells from this lethal signal, via surface IgM, suggesting that the intracellular mechanisms involved are quite similar to those of T cell death. DNA fragmentation, which has been reported in TCR/CD3 complex-mediated T cell death, apoptosis, was not involved in the B104 cell death process, but the possible involvement of DNA single-strand breaks was suggested. Observations under light microscopy and transmission electron microscopy indicated that the morphologic features of dying B104 cells resembled necrosis rather than apoptosis. B104 cell death was shown to be quite distinct from that of WEHI-231 in cell death kinetics, the mode of cell death, and the response to cyclosporin A. These data collectively indicate that the death of B104 cells resulting from surface IgM cross-linking represents a hitherto undefined mode of programmed cell death.

Anti-IgM antibody-induced cell death in a human B lymphoma cell line, B104, represents a novel programmed cell death

We investigated the mechanisms of anti-IgM antibody-induced cell death in a recently established human surface IgM+ IgD+ B lymphoma cell line, B104, the growth of which is irreversibly inhibited by anti-IgM antibody but not by anti-IgD antibody, and compared it with the cell death of T cells via TCR/CD3 complex and with the cell death of a murine anti-IgM antibody-sensitive B lymphoma cell line, WEHI-231. The rapid time course of B104 cell death and its requirements for de novo macromolecular synthesis and Ca2+ influx suggest that anti-IgM antibody-induced B104 cell death is an active Ca(2+)-dependent programmed cell death. Moreover, cyclosporin A rescued B104 cells from this lethal signal, via surface IgM, suggesting that the intracellular mechanisms involved are quite similar to those of T cell death. DNA fragmentation, which has been reported in TCR/CD3 complex-mediated T cell death, apoptosis, was not involved in the B104 cell death process, but the possible involvement of DNA single-strand breaks was suggested. Observations under light microscopy and transmission electron microscopy indicated that the morphologic features of dying B104 cells resembled necrosis rather than apoptosis. B104 cell death was shown to be quite distinct from that of WEHI-231 in cell death kinetics, the mode of cell death, and the response to cyclosporin A. These data collectively indicate that the death of B104 cells resulting from surface IgM cross-linking represents a hitherto undefined mode of programmed cell death.