bluuebunny/crossref_metadata_2025 huggingface dataset:
The human CD34 hematopoietic stem cell antigen promoter and a 3' enhancer direct hematopoietic expression in tissue culture
Authors: Burn TC , Satterthwaite AB , Tenen DG
Published: October 2019

The human CD34 hematopoietic stem cell antigen is a highly glycosylated type 1 membrane protein of unknown function. CD34 is expressed on 1% to 4% of bone marrow cells, including pluripotent stem cells and committed progenitors of each hematopoietic lineage. CD34 has also been shown to be expressed on the small vessel endothelium of a variety of tissues and on a subset of bone marrow stromal cells. We have chosen to use the human CD34 gene as model to examine the transcription factors and cis-elements required for stem cell/progenitor cell-specific gene regulation. We show here that the CD34 gene is transcriptionally regulated in tissue culture cells. Using a luciferase reporter gene, we have isolated and characterized an active CD34 promoter. A CD34- luciferase construct, containing 4.5 kb of 5′ flanking DNA from a CD34 genomic clone, was 30-fold more active in CD34+ tissue culture cells than in HeLa cells. Sequences from the 3′ end of the CD34 gene were shown to have enhancing activity in CD34+ T-lymphoblastic RPMI-8402 cells and not in CD34- U937 cells or in nonhematopoietic HeLa cells. We also show that a cytidine-guanosine island in the 5′ end of the CD34 gene is heavily methylated in two CD34- hematopoietic cell lines and demethylated in two CD34+ cell lines. Analysis of the CD34 promoter should result in the identification of stem cell/progenitor cell- specific transcription factors and should provide a means to direct the expression of heterologous genes in hematopoietic stem cells and progenitors.
T-cell subsets and suppressor cells in human bone marrow
Authors: Schmidt-Wolf IG , Dejbakhsh-Jones S , Ginzton N , Greenberg P , Strober S
Published: October 2019

To characterize immune suppressive and hematopoietic features of enriched subsets of human marrow cells, we separated these cells on Percoll density gradients. CD4+ and CD8+ T cells (CD3+) were enriched in the high-density marrow cell fractions and reduced in low-density fractions. CD4-CD8- (CD3+) T cells expressing the alpha beta T-cell antigen receptor were at least 10 times less numerous than the CD4+ and CD8+ T cells in all fractions. Purified populations of the CD4-CD8- alpha beta + T cells obtained by flow cytometry suppressed the mixed leukocyte reaction (MLR). Another population of suppressor cells that expressed neither T-cell (CD3) nor natural killer cell (CD16) surface markers was also identified. The latter cells had the phenotypic and functional characteristics of “natural suppressor” cells. Suppressor cell activity was enriched in the low-density fractions along with hematopoietic progenitors (colony-forming unit-granulocyte-macrophage and burst-forming unit-erythroid). The progenitor and suppressor cell activities were depleted in high-density fractions. The latter fractions made vigorous responses in the MLR. The low-density fractions, which accounted for less than 10% of the input marrow cells, suppressed the MLR and did not respond. Further evaluation of the low-density fractions may be of value in allogeneic bone marrow transplantation due to the reduction of CD4+ and CD8+ T cells and the enrichment of hematopoietic progenitors as well as immune suppressor cells that may inhibit graft-versus-host disease.
High levels of human glucocerebrosidase activity in macrophages of long- term reconstituted mice after retroviral infection of hematopoietic stem cells
Authors: Correll PH , Colilla S , Dave HP , Karlsson S
Published: October 2019

Gaucher disease is a leading candidate for somatic gene therapy using bone marrow (BM) cells as target tissue. Towards this end, we have constructed a retroviral vector (LG) in which the human glucocerebrosidase (GC) cDNA is driven by the Moloney murine leukemia virus (MoMLV) long terminal repeat (LTR). Day 12 to 14 colony-forming unit-spleen progenitor cells were infected by the LG virus with a 100% efficiency, and GC messenger RNA (mRNA) and protein were detected in the progeny of these cells. Tissues from long-term reconstituted mice analyzed 8 months posttransplantation with LG-infected BM contained the intact provirus at greater than 1 copy per cell, indicating effective infection of hematopoietic stem cells. Human GC mRNA generated by the viral LTR was detected in macrophages as well as other hematopoietic cells. Enzyme activity was increased fivefold and twofold in macrophages from BM and spleen, respectively, and could be precipitated with an antibody specific for human GC. Immunohistochemical analysis detected the human GC protein in 81% of the macrophages from five recipient mice. These data indicate that, after transduction of hematopoietic stem cells, the LG vector is capable of directing expression of human GC in the majority of macrophages from long-term reconstituted mice and producing enzyme levels comparable with endogenous mouse activity, suggesting that this virus may be useful in the treatment of Gaucher disease.
Large, chronic doses of erythropoietin cause thrombocytopenia in mice [see comments]
Authors: McDonald TP , Clift RE , Cottrell MB
Published: October 2019

Both large, acute doses of erythropoietin (EPO) and short-term hypoxia increase platelet counts in mice, but long-term hypoxia causes thrombocytopenia. Therefore, we tested the hypothesis that EPO injected in large, chronic doses (a total of 80 U of EPO over a 7-day period) might cause thrombocytopenia. EPO caused increased red blood cell (RBC) production, ie, increased hematocrits, RBC counts, mean cell volume (MCV), and reticulocyte counts (from P less than .05 to P less than .0005), and decreased thrombocytopoiesis, ie, decreased platelet counts, percent 35S incorporation into platelets, and total circulating platelet counts (TCPC) (P less than .0005). Femoral marrow megakaryocyte size was unchanged, but megakaryocyte number was significantly (P less than .005) reduced in mice treated with EPO. EPO- injected mice had increased spleen volumes (P less than .0005), but blood volumes (BV) were unchanged. In EPO-treated, splenectomized mice, RBC production was also increased (P less than .05 to P less than .0005) and platelet counts, TCPC, and percent 35S incorporation into platelets were decreased (P less than .05), but BV was not altered. Therefore, the decrease in platelet counts observed in EPO-treated mice was not due to increased BV or to an enlarged spleen. In other experiments, mice were rendered acutely thrombocytopenic to increase thrombocytopoiesis, and platelet and RBC production rates were determined. In mice with elevated thrombocytopoiesis, RBC counts, hematocrits, percent 59Fe RBC incorporation values, and MCV were decreased (P less than .05 to P less than .0005). Because 59Fe RBC incorporation and MCV were not elevated, the decrease in RBC counts and hematocrits does not appear to be due to bleeding. Therefore, we show that large, chronic doses of EPO increase erythropoiesis and decrease thrombocytopoiesis. Conversely, acute thrombocytopenia causes increased thrombocytopoiesis and decreased erythropoiesis. These findings support the hypothesis of competition between precursor cells of the erythrocytic and megakaryocytic cell lines (stem-cell competition) as the cause of thrombocytopenia in EPO-treated mice and the cause of anemia in mice whose platelet production rates were increased.
Vascular cell adhesion molecule-1 expressed by bone marrow stromal cells mediates the binding of hematopoietic progenitor cells
Authors: Simmons PJ , Masinovsky B , Longenecker BM , Berenson R , Torok-Storb B , Gallatin WM
Published: October 2019

Human bone marrow-derived CD34+ cells were analyzed for the expression of the beta 1-family of integrin adhesion molecules. Integrin alpha 4 beta 1 was consistently expressed by greater than 90% of CD34+ cells, including essentially all assayable granulocyte-macrophage colony- forming cells (CFU-GM) and erythroid bursts (BFU-E) as shown by fluorescence-activated cell sorting studies. Adhesion of highly enriched CD34+ cells to cultured allogeneic marrow stromal cells was largely inhibited both by monoclonal antibody to alpha 4 beta 1 and to vascular cell adhesion molecule-1 (VCAM-1), a ligand for alpha 4 beta 1. VCAM-1 was found to be expressed by bone marrow stromal elements in vitro both constitutively at low level and at high levels after treatment with cytokines. Induction of VCAM-1 was cytokine- and time- dependent with maximum levels being obtained after 4 hours of exposure to a combination of interleukin-4 and tumor necrosis factor-alpha. Cytokine-induced stromal cells bound threefold higher numbers of CFU-GM and BFU-E, this increase being abrogated by anti-alpha 4 beta 1 and anti-VCAM-1 antibodies. In addition, the adhesion to stroma of more immature progenitors, the long-term culture initiating cells, also occurred through an alpha 4 beta 1/VCAM-1-dependent mechanism. These studies identify an adhesion mechanism of potential importance in the localization of primitive progenitors within the hematopoietic microenvironment.
Human endothelial cells express integrin receptors on the luminal aspect of their membrane
Authors: Conforti G , Dominguez-Jimenez C , Zanetti A , Gimbrone MA Jr , Cremona O , Marchisio PC , Dejana E
Published: October 2019

Endothelial cells (EC) form a dynamic interface between blood and the rest of the body. EC surface properties promoting adhesion of reactive plasma proteins and/or circulating cells might be of pivotal importance for the homeostasis of blood and tissues. EC express multiple integrin receptors that promote their attachment to the subendothelial matrix proteins. Among these receptors, alpha v beta 3 is of particular relevance on EC, since it is abundantly expressed and can bind many different matrix and plasma proteins. It is still unknown whether integrin receptors are selectively located to the basal side of EC membrane or may also be exposed on the cell surface in contact with blood. This issue was addressed using different experimental approaches. First, selective surface radioiodination using lactoperoxidase (LPO)-latex beads and immunoprecipitation analysis were performed. We found that cultured EC, similarly to human skin fibroblasts (HSF), expose alpha v beta 3 on both their apical (free) and basal (substratum-attached) surfaces. This held also for other integrins such as alpha 2 beta 1, alpha 3 beta 1, alpha 5 beta 1, and alpha 6 beta 1. Immunoprecipitation data were verified by morphological techniques. Immunofluorescence and immunogold-staining of EC with alpha v beta 3, as well as with beta 1 subfamily antibodies, showed a diffuse and granular distribution of these integrins on EC surface. alpha v beta 3 and beta 1 integrins were also detected on the apical membrane of EC at higher magnification by scanning electron microscopy (SEM). Finally, data obtained on cultured EC were confirmed in vivo on immunogold-labeled ultrathin cryosections of human vessels by transmission electron microscopy (TEM). Data indicate, that in addition to their role in promoting EC attachment to extracellular matrix proteins, integrin receptors of EC can be exposed to blood-stream and eventually be available for binding of plasma proteins and circulating cells.
Induction of CD11a/leukocyte function antigen-1 and CD54/intercellular adhesion molecule-1 on hairy cell leukemia cells is accompanied by enhanced susceptibility to T-cell but not lymphokine-activated killer- cell cytotoxicity [see comments]
Authors: Jansen JH , van der Harst D , Wientjens GJ , Kooy-Winkelaar YM , Brand A , Willemze R , Kluin-Nelemans HC
Published: October 2019

Some B-cell neoplasms, including hairy cell leukemia (HCL), lack expression of the adhesion molecule leukocyte function antigen-1 (LFA- 1/CD11a). Additionally, HCL cells express relatively low amounts of intercellular adhesion molecule-1 (ICAM-1/CD54) and may therefore be an inappropriate target for recognition by T cells or lymphokine-activated killer (LAK) cells. We tested whether these molecules were inducible on HCL cells and if induction would lead to enhanced susceptibility to lysis by LAK cells or cytolytic T cells. CD11a expression was induced by incubation with interferon-alpha (IFN-alpha) or interleukin-4. CD54 was induced by culturing the cells irrespectively of the addition of cytokines. Expression of CD11a and CD54 did not enhance susceptibility to either autologous or allogeneous LAK cells. However, induction of these adhesion molecules was accompanied by enhanced susceptibility to lysis by cytotoxic T lymphocyte clones. This lysis could be reversed by the addition of anti-CD11a and anti-CD54 antibodies. Finally, we monitored the expression of CD11a and CD54 on HCL cells from patients during IFN-alpha therapy. In one of four patients monitored, we observed rapid in vivo induction of CD11a and CD54 on the leukemic cells during IFN-alpha therapy. These studies provide a model for studying immunosurveillance in HCL.
Molecular monitoring of the myl/retinoic acid receptor-alpha fusion gene in acute promyelocytic leukemia by polymerase chain reaction
Authors: Biondi A , Rambaldi A , Pandolfi PP , Rossi V , Giudici G , Alcalay M , Lo Coco F , Diverio D , Pogliani EM , Lanzi EM
Published: October 2019

The acute promyelocytic leukemia (APL) t(15;17) translocation generates a myl/retinoic acid receptor-alpha (RAR-alpha) chimeric gene that is transcribed as a fusion myl/RAR-alpha messenger RNA. Using primer sets derived from RAR-alpha and myl cDNAs, we were able to amplify the breakpoint sites of the fusion transcripts of all 35 APL RNA samples by reverse polymerase chain reaction (PCR) and nested primer approach of two rounds of amplification. DNA fragments of different size were obtained according to the chromosome 15 breakpoints (intron 3-bcr 3; exon 6-bcr 2; and intron 6-bcr 1). bcr 1 and bcr 3 represent the regions of the myl locus most frequently involved among APL (48.5 and 34.2 of cases, respectively); bcr 3 constitutes 62.5% of cases among M3V as compared with 25.9% of M3 cases. The feasibility of monitoring the APL clone by PCR analysis in five APL patients who received different treatment (chemotherapy, all-trans-retinoic acid or bone marrow transplantation) was evaluated. In five of nine bone marrow samples of patients in complete remission, t(15;17)-positive cells could be detected by PCR analysis. We conclude that PCR amplification of the myl/RAR-alpha junctions represents the easiest and rapid method for diagnosis and monitoring of the APL clone.
Correlation of CD2 expression with PML gene breakpoints in patients with acute promyelocytic leukemia [see comments]
Authors: Claxton DF , Reading CL , Nagarajan L , Tsujimoto Y , Andersson BS , Estey E , Cork A , Huh YO , Trujillo J , Deisseroth AB
Published: October 2019

The chromosomal translocation t(15;17)(q22:21) of acute promyelocytic leukemia (APL) fuses PML, a novel gene, with RAR alpha, a retinoic acid receptor gene. PML-RAR hybrid transcripts were studied in 18 cases of APL using RNA-PCR. Two forms were noted: one designated 5′, producing a 439-bp chimeric fragment, and a 3′ form, producing a pair of fragments of 765 bp and 909 bp. 5′ forms were found in 7 of the 18 cases while the other 11 patients expressed the 3′ forms. The chromosome 15 specific probes K3 and K2 were used to study genomic breakpoints in 12 APL patients. Comparison of these results with RNA PCR in 11 patients for whom both were available yielded a rearrangement pattern predictive of whether the hybrid transcript was 5′ or 3′. In this way, an additional three patients in whom DNA but not RNA was available were identified as having 3′ (downstream) breakpoints and, therefore, 3′ hybrid forms. Thus, 21 cases categorized as having 5′ or 3′ PML-RAR transcripts were analyzed for various phenotypic differences. Surface phenotyping of leukemic promyelocytes demonstrated expression of the CD2 antigen in all cases with the 5′ splice variant. Only 1 of 11 cases with the 3′ form showed CD2 expression. This difference is significant at P = .001.
Specific repression of granulocyte-macrophage and granulocyte colony- stimulating factor gene expression in interleukin-1-stimulated endothelial cells with antisense oligodeoxynucleotides
Authors: Segal GM , Smith TD , Heinrich MC , Ey FS , Bagby GC
Published: October 2019

Antisense oligodeoxynucleotides (ODNs) have been used to effect the specific inhibition of cellular gene expression. We have evaluated the application of this approach to the inhibition of interleukin-1 (IL-1)- induced granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) expression in cultured human umbilical vein endothelial cells. Antisense ODNs or control ODNs (sense ODNs or missense ODNs containing random base substitutions) were added to cultures of endothelial cells, the cells were induced with IL- 1 alpha, and the conditioned media were assayed for GM-CSF and G-CSF by quantitative bioassays and for immunoreactive GM-CSF by enzyme immunoassay. Antisense ODNs complementary to the first 15 or 18 bases of the translation start sites of GM-CSF or G-CSF mRNAs inhibited, in a concentration-dependent fashion, the IL-1-stimulated expression of the corresponding factor, but did not affect expression of the other factor. Control ODNs did not affect GM-CSF or G-CSF expression. Exposure to a GM-CSF antisense ODN, but not a control ODN, substantially reduced cytoplasmic GM-CSF mRNA levels in IL-1-stimulated endothelial cells. Neither ODN affected levels of endothelial leukocyte adhesion molecule (ELAM)1 or glyceraldehyde-3-phosphate dehydrogenase mRNAs. We conclude that antisense ODNs complementary to the translation start sites of GM-CSF or G-CSF mRNAs inhibit expression of the corresponding factor in a sequence-specific fashion and this effect is mediated, at least in part, by reduction in the cytoplasmic level of the targeted mRNA. Moreover, IL-1-induced GM-CSF or G-CSF expression does not depend on expression of the other factor.
Differentiation and functional activity of human eosinophilic cells from an eosinophil HL-60 subline: response to recombinant hematopoietic growth factors [published erratum appears in Blood 1992 Dec 1;80(11):2952]
Authors: Fabian I , Lass M , Kletter Y , Golde DW
Published: October 2019

We studied the effect of hematopoietic growth factors (granulocyte- macrophage colony-stimulating factor [GM-CSF], granulocyte [G]-CSF, interleukin (IL)-1, IL-3, IL-5, IL-6, and macrophage [M]-CSF) on differentiation and functional activity of human eosinophilic HL-60 cells (Eos-HL-60) and compared them with effects on parental HL-60 promyelocytic leukemia cells. Purified biosynthetic GM-CSF and IL-5 enhanced cell proliferation and induced eosinophilic differentiation in the eosinophilic subline in both liquid and agar cultures. IL-3 and IL- 6 stimulated cell proliferation but had no effect on cell differentiation, whereas IL-1 and G-CSF affected neither differentiation nor proliferation of Eos-HL-60 cells under the conditions tested. GM-CSF-, IL-3-, and IL-5-treated Eos-HL-60 cells showed increased O2- production in response to phorbol esters (PMA), enhanced phagocytosis of Candida albicans, and release of the enzymes arylsulfatase, beta-glucuronidase and eosinophil peroxidase (EPO). The degranulation of eosinophils induced by GM-CSF, IL-5, and IL-3 may have relevance to the potential clinical toxicity of these hematopoietins, which also stimulate eosinophilopoiesis. G-CSF had no effect on enzyme release, oxidative metabolism, or phagocytic capacity of Eos-HL-60 cells. IL-5 did not affect proliferation, differentiation, or enzyme release in promyelocytic HL-60 cells. These results indicate the specificity of IL-5 for the eosinophil lineage, confirm the effects of GM-CSF and IL-3 on eosinophilopoiesis and mature eosinophil function in a model system, and indicate the absence of G-CSF and IL-1 stimulation of eosinophils. The Eos-HL-60 line is a useful model for studying human eosinophil responses to cytokines.
Phagocytosis of Plasmodium falciparum-infected human red blood cells by human monocytes: involvement of immune and nonimmune determinants and dependence on parasite developmental stage
Authors: Turrini F , Ginsburg H , Bussolino F , Pescarmona GP , Serra MV , Arese P
Published: October 2019

The stage-dependent phagocytosis of Plasmodium falciparum-infected erythrocytes (IRBC) opsonized with nonimmune serum has been investigated. An average of 2.9 red blood cell (RBC) harboring ring- forms (RIRBC) and 7.5 RBC infected with trophozoites (TIRBC) or schizonts (SIRBC) were ingested per monocyte, in comparison with 0.8 noninfected RBC (NRBC) or 5 RBC oxidatively damaged with diamide. Abrogation of generation of complement component C3b or blockage of its binding to the phagocyte inhibited phagocytosis of RIRBC by 78% to 95% and of TIRBC by 25% to 50%. Blockage of immunoglobulin G (IgG) binding reduced phagocytosis of both RIRBC and TIRBC nonsignificantly by 14%. Preincubation of monocytes with phosphatidylserine (PS)-containing liposomes reduced phagocytosis of TIRBC by 22%, but had little effect on RIRBC. Residual, noncomplement, non-IgG-, and non-PS-dependent phagocytosis amounted to 6% to 18% of total phagocytosis in RIRBC and TIRBC, respectively. RIRBC bound 2.5 times more protein A and 3.1 times more anti-C3c (a stable derivative of C3b) antibodies, and TIRBC bound 20 times more protein A and 6.8 times more anti-C3c antibodies than NRBC. Phagocytosis of oxidatively damaged RBC and RIRBC are similar, whereas a higher portion of phagocytosis appears to be noncomplement- dependent and PS-suppressible in TIRBC. It is concluded that RIRBC generate recognition signals similar to those present in oxidatively damaged or senescent RBC. Extensive membrane modifications in TIRBC produce additional, hitherto undefined signals that induce much higher and qualitatively distinct phagocytosis.
Spectrin Jendouba: an alpha II/31 spectrin variant that is associated with elliptocytosis and carries a mutation distant from the dimer self- association site
Authors: Alloisio N , Wilmotte R , Morlé L , Baklouti F , Maréchal J , Ducluzeau MT , Denoroy L , Féo C , Forget BG , Kastally R , Delaunay J
Published: October 2019

Spectrin Jendouba (alpha II/31) was found in a Tunisian family. In the heterozygous state, it is associated with asymptomatic elliptocytosis and a minimal defect in spectrin dimer self-association. On partial digestion of spectrin with trypsin, an abnormal cleavage appeared following Lys 788. Peptide and DNA sequencing indicated that the responsible mutation is alpha 791 Asp----Glu (GAC----GAA). As in most alpha-spectrin variants associated with elliptocytosis, the change alters helix 3 of the proposed triple helical model of spectrin structure. Modified helix 3 in repeat alpha 8 is the most distant from the N-terminus of alpha-spectrin in known variants associated with elliptocytosis.
Leukotriene B4 enhances interleukin-6 (IL-6) production and IL-6 messenger RNA accumulation in human monocytes in vitro: transcriptional and posttranscriptional mechanisms
Authors: Rola-Pleszczynski M , Stankova J
Published: October 2019

Leukotriene B4 (LTB4) is a potent lipid mediator of inflammation, and some of its bioactivities may involve inflammatory cytokines. Moreover, it may participate in myelopoiesis, either directly or via the induction of cytokines and growth factors. When human monocytes were cultured in the presence of graded concentrations of LTB4, significant stimulation of production of bioactive and immunoreactive interleukin-6 (IL-6) was observed. Nanomolar concentrations of LTB4 were optimal and the LTB4 receptor antagonist LY 255283 could block its activity. The omega-oxidation products of LTB4, 20-OH-LTB4 and 20-COOH-LTB4, were only 22% and 2% effective, respectively. LTA4 was also effective in stimulating IL-6 production, but only at micromolar concentrations, whereas 5-HETE and 12-epi-LTB4 were ineffective. The signaling induced by LTB4 did not seem to involve protein kinase C or A, but rather a tyrosine kinase, as suggested by its inhibition with genistein. LTB4 induced an accumulation of IL-6 messenger RNA (mRNA) in treated monocytes with a dose-response similar to that of IL-6 protein production. Whereas IL-6 mRNA half-life in untreated cells was approximately 1 hour, it was extended to 3 hours in LTB4-treated monocytes. Moreover, nuclear transcription of IL-6 mRNA was augmented at 30 minutes by a factor of 5 in LTB4-treated cells. Pretreatment of cells with cyclohexamide before exposure to LTB4 superinduced IL-6 message expression, but partially inhibited the effect of LTB4 on IL-6 mRNA accumulation, suggesting that newly synthesized proteins may be involved in the transcriptional activation of the IL-6 gene by LTB4. These findings constitute a first demonstration that LTB4 stimulates IL- 6 production and that the underlying mechanisms involve both increased IL-6 gene transcription and message stabilization. This may constitute an important mechanism through which rapidly produced mediators may modulate the subsequent production of regulatory or growth-promoting cytokines.
Crossreacting human lymphoma idiotypes
Authors: Rudders RA , Levin A , Jespersen D , Zacks J , Delellis R , Ranger A , Krontiris T
Published: October 2019

We have examined an unselected series of 72 lymphomas of diverse histologies with a panel of mouse monoclonal antibodies specific for human B-lymphoma-derived Ig idiotypes (anti-ids) to determine the nature and extent of id/anti-id crossreactivity. The anti-id antibodies were prepared from Ig isolated from seven follicular center cell lymphomas by heterohybridoma technique. Thirty-six of 75 individual anti-ids obtained in this manner were further selected based on their reactivity with highly restricted or private idiotypic determinants. Twelve of the 72 (17%) lymphoma biopsies reacted with one or more of the 36 anti-ids that detect private determinants. A pool consisting of five individual antibodies would have detected 11 of the 12 crossreacting tumors. Staining of tumor cell populations was homogeneous in the positive cases, suggesting uniform idiotype expression. If there was a segregated staining pattern, it was generally related to the presence of CD3+ T cells in the section. These follicular center cell-derived anti-ids cross-reacted with follicular center cell tumors of all histologic grades with frequencies ranging from 13% to 50%. The structural basis for the crossreactivity of our lymphoma-derived private anti-ids is as yet not known. However, the reactivity of certain anti-ids with both kappa- and lambda-expressing tumors suggests a biased use of V gene segments in these crossreactive clones that is probably related to the VH gene. These data suggest the possibility that lymphoma may develop in a highly restricted pool of normal differentiated B cells or in B-cell subsets that express a limited repertoire of unmutated VH gene segments.
Stimulation of phosphoinositol turnover and protein kinase C activation by granulocyte-macrophage colony-stimulating factor in HL-60 cells
Authors: Nishimura M , Kaku K , Azuno Y , Okafuji K , Inoue Y , Kaneko T
Published: October 2019

Phosphoinositol turnover, diacylglycerol generation, protein kinase C (PK-C) activity, and intracellular cyclic nucleotides were studied in an established human leukemia cell line, HL-60, in response to one of the hematopoietic cytokines, granulocyte-macrophage colony-stimulating factor (GM-CSF). Continuous exposure of HL-60 cells to GM-CSF induced the cell differentiation that was evaluated by the nitroblue tetrazolium (NBT) reducing activity. GM-CSF also exhibited a proliferative effect on HL-60 cells. GM-CSF at 1 nmol/L, an optimal concentration for cell growth and cell differentiation, induced significant changes in the intracellular inositoltriphosphate (IP3). Diacylglycerol generation was also stimulated by GM-CSF treatment. GM- CSF increased the membrane PK-C activity by 10-fold of the control, whereas no measurable change in cyclic nucleotides was observed. These data indicated that phosphoinositol turnover and the activation of PK-C were included in the GM-CSF signal transducing pathway in HL-60 cell. Phosphoinositol response leading to PK-C activation may act as a trigger signal of cell differentiation by GM-CSF.
Multiple Rh messenger RNA isoforms are produced by alternative splicing
Authors: Le Van Kim C , Cherif-Zahar B , Raynal V , Mouro I , Lopez M , Cartron JP , Colin Y
Published: October 2019

Three Rh-related cDNAs have been isolated from a human bone marrow cDNA library and by polymerase chain reaction (PCR) amplification of human bone marrow and erythroblast mRNAs. They potentially encode a family of Rh protein isoforms that exhibit several unexpected structural properties as compared with the Rh polypeptide encoded by the cDNA clone identified previously. These modifications include several peptide deletions, the predicted alteration of Rh protein topology within the cell membrane, variations in the number and surface exposition of cysteine residues, and the generation of new C-terminal polypeptide segments caused by frameshift mutations. The four Rh mRNAs now described correspond to different splicing isoforms transcribed from the same Rh gene, and all exist in the same cell lineage (erythroid). Moreover, PCR experiments indicated that at least three of these RNA species exist in reticulocytes from donors with different commonly expressed Rh phenotypes. Although the translated proteins have not yet been characterized, these results suggest that the two genes at the RH locus may direct the synthesis of several protein species possibly corresponding to different Rh antigenic variants.
A c-kit ligand, recombinant human stem cell factor, mediates reversible expansion of multiple CD34+ colony-forming cell types in blood and marrow of baboons
Authors: Andrews RG , Bartelmez SH , Knitter GH , Myerson D , Bernstein ID , Appelbaum FR , Zsebo KM
Published: October 2019

The ligand for the human c-kit, recombinant human stem cell factor (SCF), was administered to baboons at doses of 200, 100, 50, 25, and 10 micrograms/kg/d. SCF induced a dose-dependent expansion of hematopoietic colony-forming cells (CFC) of multiple types in both blood and marrow, including colony-forming unit (CFU) granulocyte- monocyte, burst-forming unit-erythroid, CFU-MIX, and high proliferative potential-CFC. These changes were associated with a dose-dependent leukocytosis, involving all leukocyte lineages, a reticulocytosis, and increases in marrow cellularity. At 200 micrograms/kg/d of SCF, CFC in blood were increased 10-fold to greater than 100-fold. This correlated with an increased frequency of CD34+ cells in blood. The frequency of CFC in blood approached that of marrow in some animals. These changes were reversed within 7 to 14 days of stopping SCF. The results of these studies suggest a role for the c-kit ligand in stimulating the expansion of multiple CFC types in blood and marrow for potential therapeutic purposes.
Identification of a point mutation in factor XIII A subunit deficiency
Authors: Board P , Coggan M , Miloszewski K
Published: October 2019

Oligonucleotide primers have been designed for the amplification of all 15 exons of the human coagulation factor XIII A subunit gene. Each exon and its intron flanking regions has been amplified and sequenced from a patient with severe A subunit deficiency. A single G to A transition in the last base of exon 14 has been identified in the homozygous proband and in his heterozygous parents. The mutation would result in the substitution 681 Arg to His in the mature protein product. However, because the mutation is at a splice junction, the deficiency may result from a defect in pre-messenger RNA splicing.
Detection of human T-cell leukemia/lymphoma virus, type II, in a patient with large granular lymphocyte leukemia
Authors: Loughran TP Jr , Coyle T , Sherman MP , Starkebaum G , Ehrlich GD , Ruscetti FW , Poiesz BJ
Published: October 2019

We studied a patient with large granular lymphocyte (LGL) leukemia for evidence of human T-cell leukemia/lymphoma virus (HTLV) infection. Serum from this patient was positive for HTLV-I/II antibodies by enzyme- linked immunosorbent assay (ELISA) and was confirmed positive in Western blot and radioimmunoprecipitation assays. Results of a synthetic peptide-based ELISA showed that the seropositivity was caused by HTLV-II and not HTLV-I infection. Analyses of enzymatic amplification of DNA from bone marrow sections using the polymerase chain reaction (PCR) were positive for HTLV-II specific gag, pol, env, and pX gene sequences. Cloning and sequencing of amplified products showed that the HTLV-II pol and pX sequences in patient DNA differed from the sequences of 17 other HTLV-II isolates examined in our laboratory. HTLV infection may have a role in some patients in the pathogenesis of LGL leukemia.
Effects of human stem cell factor (c-kit ligand) on proliferation of myeloid leukemia cells: heterogeneity in response and synergy with other hematopoietic growth factors
Authors: Pietsch T , Kyas U , Steffens U , Yakisan E , Hadam MR , Ludwig WD , Zsebo K , Welte K
Published: October 2019

A novel hematopoietic growth factor, the stem cell factor (SCF), for primitive hematopoietic progenitor cells has recently been purified and its gene has been cloned. In this study we tested the mitogenic activity of recombinant human SCF on myeloid leukemia cells as well as the expression of its receptor. We have investigated the proliferation of 31 myeloid leukemia cell lines as well as fresh myeloid leukemic blasts from 17 patients in a 72-hour 3H-thymidine uptake assay in the presence of various concentrations of recombinant human (rh) SCF alone or in combination with saturating concentrations of granulocyte- macrophage colony-stimulating factor (GM-CSF), G-CSF, M-CSF, interleukin-3 (IL-3), or erythropoietin (EPO). Only five of 31 lines, but fresh leukemic blasts from 12 of 17 patients with acute myeloid leukemia (AML), significantly responded to SCF. The responding cell lines were of the acute promyelocytic, chronic myeloid, megakaryoblastic, and erythroleukemia origin, the responding blast preparations of all French-American-British subtypes. Synergistic activities of SCF were found with G-CSF, GM-CSF, EPO, and IL-3. To determine the SCF binding sites on leukemic cells, we used 125I- radiolabeled SCF in Scatchard analysis and cross-linking studies. The leukemic cell lines responding to SCF expressed from 2,300 up to 29,000 binding sites per cell. The SCF receptor expression was downregulated in vitro by the presence of its ligand. Cross-linking studies demonstrated a 150-Kd SCF receptor on the surface of all responding myeloid leukemias. This study suggests that SCF may be an important factor for the growth of myeloid leukemia cells, either as a direct stimulus or as a synergistic factor for other cytokines. Furthermore, using polymerase chain reaction analysis of total RNA from the myeloid leukemia lines, we found expression of SCF-mRNA in 17 of 30 lines, suggesting autocrine mechanisms in the growth of a subgroup of leukemic cells by coexpression of SCF and its receptor.
Functional expression of c-kit by acute myelogenous leukemia blasts is enhanced by tumor necrosis factor-alpha through posttranscriptional mRNA stabilization by a labile protein
Authors: Brach MA , Buhring HJ , Gruss HJ , Ashman LK , Ludwig WD , Mertelsmann RH , Herrmann F
Published: October 2019

The c-kit proto-oncogene encodes a transmembrane glycoprotein identical to the receptor for the recently cloned stem cell factor (SCF). The present study examines constitutive synthesis of transcripts in primary acute myelogenous leukemia (AML) blasts and the effects of recombinant human tumor necrosis factor (TNF)-alpha on c-kit mRNA expression in these cells. The c-kit transcripts were detectable at low levels in 10 of 10 different AML samples investigated. TNF treatment of AML cells was associated with enhanced c-kit mRNA expression in all specimens. Nuclear run-on transcription assays indicated that the c-kit gene was transcriptionally active in all leukemias examined and the rate of transcription was unaffected by exposure to TNF, suggesting posttranscriptional control mechanisms of c-kit mRNA accumulation. In the absence of TNF, the half-life of c-kit transcripts was 2 to 3 hours, while in TNF-treated AML cells, c-kit half-life was found to be 5 to 9 hours. Inhibition of protein synthesis reduced TNF-induced c-kit mRNA expression by Northern blot analysis, but did not affect the rate of c-kit gene transcription. In the presence of inhibition of protein synthesis, the half-life of c-kit transcripts in TNF-induced leukemia cells decreased to 2 to 4 hours. These findings indicate that levels of c-kit mRNA are controlled by a labile protein that is involved in TNF- mediated stabilization of c-kit transcripts. The effects of TNF-alpha also extended to the protein level in that TNF-alpha treatment of primary AMLs was associated with enhanced surface expression of the SCF receptor by some of these cells. While exogenous SCF induced clonogenic growth of all primary AML samples investigated, TNF-alpha failed to stimulate leukemic cells to proliferate. However, the combination of SCF and TNF-alpha resulted in synergistic growth stimulation in seven of nine different AML specimens investigated. The finding of transmodulation of the SCF receptor through posttranscriptional modifications might further contribute to our understanding of the synergistic interplay of TNF-alpha and SCF.
Contact-induced neutrophil activation by platelets in human cell suspensions and whole blood
Authors: Ruf A , Schlenk RF , Maras A , Morgenstern E , Patscheke H
Published: October 2019

Platelet-dependent activation of polymorphonuclear neutrophils (PMNL) was investigated with a lumi-aggregometer in heparinized whole blood and platelet-PMNL suspensions. The lumi-aggregometer allowed us to simultaneously monitor increases in impedance or light transmission as consequences of platelet aggregation and luminol-enhanced chemiluminescence (CL) as a measure of the oxidative burst in PMNL. Aggregation and platelet-PMNL contacts were also checked by light and electron microscopy. In whole blood, adenosine diphosphate (ADP) and the thromboxane A2 mimetic U 46619 induced the aggregation (increase in impedance) and the CL, which were both suppressed by EDTA, arginyl- glycyl-aspartyl-serine (RGDS) peptide, and the absence of stirring. In contrast, FMLP caused only CL that was unaffected by EDTA, RGDS peptide, and nonstirring. Similar observations were obtained with mixed suspensions containing washed platelets and PMNL at their physiologic concentrations. ADP, U 46619, and thrombin induced both aggregation (increase in light transmission) and CL, whereas FMLP caused CL but only very weak aggregation. Exogenous fibrinogen strongly enhanced the effects of ADP and U 46619. Iloprost, EDTA, RGDS peptide, red blood cell (RBC) ghosts, and nonstirring inhibited the effects induced by the platelet agonists, but were ineffective on the CL induced by FMLP. Treatment of platelets with aspirin did not affect the CL of PMNL induced by platelets. Microscopic examination, the requirements of stirring, Ca2+, and fibrinogen, and the inhibitory effects of RGDS peptide and RBC ghosts show that stimulated platelets activate PMNL in a contact-dependent manner that depends on fibrinogen binding. This was confirmed by the immunochemical demonstration of fibrinogen (but not of fibronectin) in the contact spaces between activated platelets and PMNL. Because supernatants and lysates of resting or thrombin- stimulated platelets did not induce the CL of PMNL, soluble agonists did not appear to be involved. Nonstimulated washed platelets also caused CL of PMNL that required stirring and Ca2+ and was inhibited by RBC ghosts. No CL occurred in unstimulated stirred whole blood, suggesting that a preactivation of platelets during the preparation may be responsible for the effects of unstimulated washed platelets. The results show that platelets provide a strong stimulus for PMNL that requires intercellular contact. Fibrinogen exposure on the platelet surface seems to be necessary for the activation of PMNL by stimulated platelets.
Antithrombotic properties of L-cysteine, N-(mercaptoacetyl)-D-Tyr-Arg- Gly-Asp-sulfoxide (G4120) in a hamster platelet-rich femoral vein thrombosis model
Authors: Imura Y , Stassen JM , Bunting S , Stockmans F , Collen D
Published: October 2019

Platelet aggregation plays an important role in the pathogenesis in arterial thrombotic disorders. The binding of fibrinogen via the Arg- Gly-Asp (RGD) recognition sequence to the platelet glycoprotein IIb/IIIa (GPIIb/IIIa) receptor is an essential step of platelet aggregation induced by various physiologic agonists, and RGD-containing peptides that bind to the GPIIb/IIIa receptor inhibit thrombus formation in vivo. L-cysteine, N-(mercaptoacetyl)D-tyrosyl-L- arginylglycyl-L alpha-aspartyl-cyclic (1----5)-sulfide, 5-oxide (G4120), a cyclic RGD-containing synthetic pentapeptide, inhibits adenosine diphosphate (ADP)-induced platelet aggregation with 50% inhibition (IC50) at a concentration of 0.05 microgram/mL in human plasma, 0.12 microgram/mL in hamster plasma, and 11 micrograms/mL in rat plasma. Corresponding values for the linear tetrapeptide Arg-Gly- Asp-Phe (RGDF) were 7 and 100 micrograms/mL in human and hamster plasma. The antithrombotic effects of G4120 and RGDF were evaluated in a hamster model consisting of a mural platelet-rich femoral vein thrombus induced by standardized endothelial cell damage. Bolus intravenous injection of G4120 was followed by a biphasic disappearance of G4120 from plasma with t1/2 alpha of 3.7 minutes and t1/2 beta of 63 minutes, corresponding to a plasma clearance of 5.2 +/- 0.68 mL/min. Bolus intravenous injection of G4120 inhibited ex vivo platelet aggregation with 0.5 mumol/L ADP and in vivo thrombus formation in a dose-dependent manner, with ID50 of 11 and 11 micrograms/kg, respectively. Bolus injection of RGDF inhibited in vivo thrombus formation; 43% inhibition was obtained at a dose of 30 mg/kg. Thus, this hamster platelet-rich femoral vein thrombosis model may be useful for the investigation of the antithrombotic properties of platelet GPIIb/IIIa antagonistic peptides. The cyclic synthetic peptide G4120 appears to have a very potent antithrombotic activity in vivo.
Neuropeptide Y (NPY) synthesis in lymphoblasts and increased plasma NPY in pediatric B-cell precursor leukemia
Authors: Kogner P , Ericsson A , Barbany G , Persson H , Theodorsson E , Bjork O
Published: October 2019

Neuropeptide Y (NPY), a regulatory peptide in both the central and peripheral nervous systems, has recently been found in neuroendocrine tumors as well as in the bone marrow of rat and certain autoimmune mice, but not in human bone marrow. To investigate a possible role for NPY in the human hematopoietic system, we have prospectively studied NPY-like immunoreactivity in plasma (P-NPY-LI) and NPY mRNA in bone marrow from children with acute leukemia. Northern blot showed high levels of NPY mRNA in bone marrow and peripheral lymphoblasts from children with B-cell precursor leukemia. In situ hybridization showed NPY mRNA in malignant B-cell precursor lymphoblasts. No NPY mRNA was detected in the bone marrow of children with T-cell leukemia. P-NPY-LI was higher (P less than .001) in 51 children with leukemia (200:50 to 385 pmol/L, median:interquartile range) compared to 51 age-matched healthy controls (37:20 to 52 pmol/L). P-NPY-LI was higher (P less than .001) in those with favorable clinical risk classification. Elevated P- NPY-LI, compared with the upper age-adjusted reference limit, was only found in children with B-cell precursor leukemia (31 of 40), whereas all children with B-cell, T-cell, or myeloid leukemia (n = 11) had normal P-NPY-LI (P less than .001). During the 2- to 46-month follow- up, children with elevated P-NPY-LI had better (P less than .001) outcome compared to those with normal P-NPY-LI (79.4% v 34.6% probability for event-free survival).
Use of alpha interferon for the treatment of relapse of chronic myelogenous leukemia in chronic phase after allogeneic bone marrow transplantation
Authors: Higano CS , Raskind WH , Singer JW
Published: October 2019

Eighteen patients with relapse of chronic myelogenous leukemia (CML) after allogeneic bone marrow transplantation (BMT) were treated with recombinant human alpha 2a interferon (IFN). Relapse was defined as greater than 90% metaphases containing the Philadelphia chromosome (Ph) and hematologic abnormalities consistent with chronic-phase (CP) CML. There were 11 males and seven females, with a median age of 38 years (range, 3 to 55). Three patients relapsed after second BMT. Only one patient had received T-cell-depleted marrow initially. The initial IFN dose of 3 x 10(6) U/m2/d was escalated to the maximum tolerated dose or to a maximum of 6 x 10(6) U/m2/d. IFN controlled the white blood cell (WBC) counts in 14 of 16 patients who had abnormal counts, and in all six patients with an elevated platelet count. Six patients (33%) have had a complete disappearance of the Ph and two have had a partial response (less than 35% Ph+ metaphases). One patient has a decrease in Ph+ metaphases after 9 months of IFN. Five patients had no significant cytogenetic response after 9 to 12 months, and four developed clinical accelerated phase or blast crisis after 3 to 6 months on therapy. Of four patients with a sex marker, the Ph- population was of donor origin in three and of host origin in one. Clonal cytogenetic abnormalities other than Ph were present in 13 patients and did not predict for lack of response to IFN. IFN is effective in suppressing the Ph clone in some patients who relapse with CML after allogeneic BMT and controls the blood counts in the majority.
Identification of lysosome-associated membrane protein-2 as an activation-dependent platelet surface glycoprotein
Authors: Silverstein RL , Febbraio M
Published: October 2019

Platelets undergo biochemical and morphologic changes when stimulated that greatly alter their function and contribute to their role in thrombosis and hemostasis. We recently identified and cloned the cDNA for a platelet surface glycoprotein expressed on activated, not resting cells. We found that this protein, lysome-associated membrane protein-1 (LAMP-1), is an integral membrane protein of the lysosome that translocated to the surface membrane when platelets were stimulated by a strong agonist. We now show with immunofluorescence flow cytometry that LAMP-2, a lysosomal membrane protein that shares approximately 30% homology with LAMP-1, is also expressed preferentially on the surface of activated platelets. Equilibrium binding studies with 125I-anti-LAMP- 2 IgG showed approximately 1,100 binding sites per thrombin-stimulated platelet and less than 50 per resting platelet. Sucrose gradient ultracentrifugation fractionation of resting platelet sonicates showed that LAMP-2 colocalized with LAMP-1 and with lysosomal enzymes, and not with thrombospondin or serotonin, which are markers of the two other platelet granule compartments, alpha-granules and dense granules. LAMP- 2 surface expression was minimal in response to platelet stimulation by weak agonists such as epinephrine and ADP. These data show that LAMP-2, like LAMP-1, translocates from the lysosomal membrane compartment to the surface membrane when platelets are activated. Regulated surface expression of these heavily glycosylated proteins may play a role in the adhesive, prothrombotic phenotype of these cells.