bluuebunny/crossref_metadata_2025 huggingface dataset:
Monoclonal antibodies to leukocyte integrins CD11a/CD18 and CD11b/CD18 or intercellular adhesion molecule-1 inhibit chemoattractant-stimulated neutrophil transendothelial migration in vitro
Authors: Furie MB , Tancinco MC , Smith CW
Published: October 2019

Intercellular adhesion molecule-1 (ICAM-1) is present on the endothelium and binds to one or more members of the CD11/CD18 family of leukocyte surface integrins. To assess the role of these molecules in mediating chemotaxis of neutrophils across the endothelium, an in vitro model consisting of monolayers of human umbilical vein endothelial cells (HUVEC) grown on amniotic connective tissue was used. Neutrophils placed on the apical sides of these cultures migrated across the endothelium in response to chemoattractants added basally. Monoclonal antibodies (MoAbs) to CD11a, CD11b, and CD18 on the neutrophils inhibited this migration by 52% +/- 11%, 29% +/- 19%, and 90% +/- 7%, respectively. An MoAb to ICAM-1 inhibited transendothelial chemotaxis of the leukocytes by 55% +/- 16%. Inhibition was mediated by binding of the MoAb to ICAM-1 on the HUVEC, rather than by any direct effect of the antibody on the neutrophils. When used in combination, MoAbs to CD11a and to CD11b inhibited migration in a nearly additive fashion. A similar additive effect was observed when MoAbs to CD11b and to ICAM-1 were used together. In contrast, MoAbs to CD11a and to ICAM-1 produced no more inhibition when used in combination than when added singly. These results show that ICAM-1, CD11a/CD18, and CD11b/CD18 all participate in controlling migration of neutrophils across endothelial monolayers in response to chemotactic agents.
Late failure of autologous marrow grafts in lethally irradiated dogs given anti-class II monoclonal antibody
Authors: Greinix HT , Ladiges WC , Graham TC , Maslan S , Raff RF , Sandmaier BM , Appelbaum FR , Schuening FG , Deeg HJ , Storb R
Published: October 2019

We established a model of canine marrow autografts after 9.2 Gy total body irradiation (TBI) to study the role of class II antigens in hematopoietic stem cell growth and differentiation. Twenty dogs were given 9.2 Gy TBI, marrow, and intravenous (IV) murine anti-class II monoclonal antibody (MoAb). Infusion of 0.6 mg/kg/d of MoAb H81.98.21, an IgG2a reactive with HLA-DR, on days 0 to 4 after TBI did not prevent initial engraftment, but dogs died with late graft failure. MoAb B1F6, an IgG2a reactive with HLA-DR + DP, had no adverse effect on engraftment, although both MoAbs detect antigens on stem cells. The critical time for the effect of MoAbs is the first 4 days after transplantation. Our findings argue against several pathogenetic mechanisms, including removal of MoAb-coated stem cells by the reticuloendothelial system (RES), canine complement-mediated cytotoxic effects on stem cells, antibody-dependent cellular cytotoxicity, and inactivation of MoAb-coated cells by dog anti-mouse antibody. To distinguish between MoAb-induced damage to microenvironment (ME)/accessory cells (AC) and late graft failure from a lack of pluripotent stem cells, three dogs were given TBI, a marrow autograft, and MoAb H81.98.21 on days 0 to 4; one, given thoracic duct cells on day 6, developed graft failure; the other two, given marrow depleted of AC by L-leucyl L-leucine o-methyl ester (Leu-Leu-OMe), had sustained grafts. Findings support the notion that originally transplanted pluripotent stem cells are no longer present on day 6 and that the ME is functional and able to support newly injected stem cells.
Binding of tissue plasminogen activator to human monocytes and monocytoid cells
Authors: Felez J , Chanquia CJ , Levin EG , Miles LA , Plow EF
Published: October 2019

Monocytes and monocytoid cell lines previously have been shown to express receptors for plasminogen and urokinase (u-PA). In the present study, the monocytoid cell lines, U937 and THP-1, are shown to bind tissue plasminogen activator (t-PA) in a specific, saturable, and reversible manner. These cells bound t-PA with low affinity (kd = 0.67 to 0.97 mumol/L) and high capacity (0.71 to 3.3 x 10(6) receptors/cell). Human peripheral blood monocytes bound t-PA with a kd (0.9 mumol/L) similar to that of the monocytoid cells but with a lower capacity (0.17 x 10(6) sites/cell). These binding parameters also were similar to the low-affinity interaction of t-PA with endothelial cells as measured with the cells in suspension (kd = 0.73 mumol/L and 1.1 x 10(6) sites/cell). Lysine analogues and active or diisopropylfluorophosphate-inactivated u-PA inhibited t-PA binding to monocytes, monocytoid cells, and endothelial cells with similar IC50 (concentration producing 50% inhibition) values, suggesting that the same recognition specificity mediates t-PA binding to all of these cell types. The existence of a high-affinity binding site for t-PA on monocytoid cells was also explored in detail. Unlike endothelial cells where plasminogen activator inhibitor-1 has been implicated in mediating a high-affinity interaction of t-PA with the cells, no evidence for a role of this inhibitor in ligand binding to the monocytoid cells was found. Furthermore, using both high and low 125I-t- PA concentrations, competition analyses with lysine analogues or u-PA, or treatment of the cells with carboxypeptidase B, failed to indicate the presence of distinguishable classes of t-PA binding sites. In sum, low-affinity receptors for t-PA are expressed at high density on monocytes and monocytoid cells, identifying a new element in the fibrinolytic arsenal of these cells.
Binding of fluorescein-labeled anaphylatoxin C5a to human peripheral blood, spleen, and bone marrow leukocytes
Authors: Werfel T , Oppermann M , Schulze M , Krieger G , Weber M , Gotze O
Published: October 2019

The expression of C5a receptors (C5aR) on human leukocytes was evaluated by flow cytometry using fluorescein-labeled human C5a (C5a- F). Granulocytes and CD14+ mononuclear cells (MNL) but not CD3+, CD20+, CD16+, CD56+, or CD11b+ lymphocytes in peripheral blood and spleen bound C5a-F. C5a-F binding was saturable and inhibitable by anti-C5a monoclonal antibody (MoAb) C17/5 or unlabeled C5a. During hemodialysis, which led to the generation of C5a, only granulocytes and monocytes increased their expression of the adhesion molecule CD11b (CR3). In vitro, C5a induced an increase of CR3 and p 150/95 (CD11c/CR4) only on myeloid cells. However, treatment of leukocytes with phorbol 12- myristate 13 acetate increased CR3 and CR4 expression on both myeloid cells and a lymphocyte subpopulation. Stimulation of MNL in mixed lymphocyte cultures or by treatment with conditioned medium or with IFN- gamma did not induce binding sites for C5aR on lymphocytes and reduced the binding of C5a-F to monocytes. The expression of C5aR on low- density bone marrow cells was analyzed by setting appropriate gates during flow cytometry. Cells that bound C5a-F were found in all populations that contained granulocyte and monocyte precursors, but not in lymphocyte precursor populations. All C5aR+ bone marrow cells were CD34 and expressed high levels of CR3, which suggests a late appearance of C5aR during myeloid cell maturation. Our results indicate that C5aR is exclusively expressed on myeloid cells within the hematopoetic cell population.
Primary myelodysplastic syndromes: diagnostic and prognostic significance of immunohistochemical assessment of bone marrow biopsies
Authors: Mangi MH , Mufti GJ
Published: October 2019

Material from 63 cases with primary myelodysplastic syndromes (P-MDS) (French-American-British [FAB] types: refractory anemia [RA] = 21; RA with ring sideroblasts [RARS] = 8; RA with excess of blasts (RAEB) = 10; RAEB in transformation (RAEBt) = 6; chronic myelomonocytic leukemia [CMML] = 10 and unclassifiable = 8, ie, bone marrow aspiration was inadequate and stringent FAB criteria were not applicable) was analyzed for bone marrow histologic and immunohistochemical patterns. Standard Giemsa, hematoxylin and eosin (H&E) and reticulin stains were used for morphologic assessment. To identify the cell lineage precisely, chloroacetate esterase staining and an indirect immunoperoxidase technique using mouse monoclonal antibodies CD15, CD68, HLA-DR, and rabbit polyclonal CD3 and UEA-1 (lectin) was developed on formalin- fixed paraffin embedded bone marrow biopsies (BMB). The immunohistochemical assessment permitted accurate identification of dysplastic features such as mononuclear and binuclear megakaryocytes, Pelger-Huet neutrophils, and binuclear erythroblasts. Additional bone marrow histologic and immunohistochemical features observed were heterogeneity of immunohistochemical staining in various cell lineages, megakaryocytic emperipolesis, alteration of bone marrow microarchitecture, intravascular clusters of hematopoietic cells, and the types of benign lymphoid aggregates. The nature of abnormally localized immature precursors (ALIP) was discerned. Three types of clusters of immature cells were found that were difficult to distinguish on Giemsa and H&E morphology, these were erythroid aggregates (n = 18); megakaryocytic aggregates (n = 4), and immature granulocytic and monocytic aggregates (n = 32). The bone marrow histologic and immunohistologic patterns permitted the identification of four groups of clinical relevance: Group 1, cases with predominant erythroid hyperplasia and without ALIP (n = 15); group 2, cases with prominent myeloid hyperplasia and presence of ALIP (n = 32); group 3, cases with hypoplastic MDS (n = 10); and group 4, cases with hyperfibrotic MDS (n = 6). Statistical analysis showed a significant difference in survival and leukemic transformation between groups 1, 2, 3, and 4, with cases in group 2 showing the worst prognosis with early death due to increased propensity to leukemic transformation and cytopenia-related complications (P less than .0001). We conclude that immunohistochemistry is feasible on routinely processed BMB and the information obtained is of diagnostic and prognostic importance in P- MDS. The phenotype of ALIP varies with the morphologic and histologic subtypes of MDS and the term should be reserved for cases in whom the clusters in the intertrabecular region are of myeloid (granulocytic and monocytic) lineage on immunohistochemistry.
Characteristics of red blood cell populations fractionated with a combination of counterflow centrifugation and Percoll separation
Authors: Bosch FH , Werre JM , Roerdinkholder-Stoelwinder B , Huls TH , Willekens FL , Halie MR
Published: October 2019

Red blood cell (RBC) fractions were studied after separation of whole blood by means of counterflow centrifugation, Percoll column (Pharmacia, Uppsala, Sweden), and a combination of both separation techniques. Mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH), and hemoglobin A1c (HbA1c) were measured in each fraction. From the results it was obvious that the combination of both techniques was the best separation technique of these three. MCV had a good correlation with cell age as measured with HbA1c concentration gradient; MCH and MCHC less so. MCV and MCH decreased in parallel to an increase in HbA1c. MCHC increased with increasing HbA1c. From these data it is concluded that there is a steadily ongoing loss of cellular hemoglobin and proportionally more cellular water during the life of the RBC.
Localization of the platelet-specific HPA-2 (Ko) alloantigens on the N- terminal globular fragment of platelet glycoprotein Ib alpha
Authors: Kuijpers RW , Ouwehand WH , Bleeker PM , Christie D , von dem Borne AE
Published: October 2019

The human platelet-specific alloantigens HPA-2a and HPA-2b (= Kob and Koa) together constitute a biallelic antigen system. The HPA-2 antigens have not, to date, been located on a particular platelet membrane molecule. Here, we describe the localization of these antigens on platelet glycoprotein (GP) Ib alpha. Platelets from two patients with the Bernard-Soulier syndrome (BSS) were HPA-2(a-,b-) in the immunofluorescence test with HPA-2 alloantibodies on chloroquine- treated platelets. With monoclonal antibody (MoAb) immobilization of platelet antigen assay (MAIPA), positive reactions were obtained only when MoAbs against the platelet GPIb/IX complex were used in combination with anti-HPA-2a or -2b alloantibodies and normal donor platelets. By immunoprecipitation under nonreducing and reducing conditions a protein of 160 Kd and 145 Kd, respectively, was precipitated by the anti-HPA-2a serum. A protein migrating identically to this was precipitated by anti-GPIb MoAb. Normal donor platelets became HPA-2(a-,b-) after elastase treatment, suggesting that anti-HPA- 2 antibodies bind to the N-terminal elastase-sensitive part of GPIb alpha. Anti-HPA-2a antibodies inhibited the ristocetin-induced agglutination of HPA-2a-positive platelets but not of HPA-2a-negative platelets, indicating that the epitopes recognized by these alloantibodies are localized in the proximity of the von Willebrand- factor-binding domain. Together, these data provide evidence that the HPA-2 alloantigens are located on the N-terminal globular elastase- sensitive part of GPIb alpha. Furthermore, we show that the recently described Siba antigen is probably identical to HPA-2a.
Recombinant rat stem cell factor stimulates the amplification and differentiation of fractionated mouse stem cell populations
Authors: Williams N , Bertoncello I , Kavnoudias H , Zsebo K , McNiece I
Published: October 2019

The role of recombinant rat stem cell factor (rrSCF) was studied on defined primitive bone marrow cell populations. In agar culture of 500 lineage-negative/Sca-1-positive (Lin-/Sca-1+) cells, rrSCF alone stimulates small colonies of predominantly granulocytic cells. The combinations of rrSCF plus interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), or macrophage CSF (CSF-1) stimulated primitive progenitor cells defined as high proliferative potential colony-forming cells (HPP-CFC). Synergistic increases in total colony numbers were obtained with rrSCF plus GM-CSF, granulocyte CSF (G-CSF), CSF-1, or IL-6, but not IL-1 or IL-3. Lin-/Sca-1+ cells were incubated in liquid culture at 3,000 cells/mL for 6 days in the presence of rrSCF alone or in combination with other growth factors. The total number of cells was increased twofold in the presence of rrSCF, with the progeny primarily myeloid in nature. The greatest increase in cell number was obtained with rrSCF plus IL-3, where the cell number increased 40-fold. These factors also stimulated an increase in HPP-CFC (10-fold) and GM-CFC (500-fold). To determine if these interactions were direct, single Lin-/Sca-1+ cells were sorted into microtiter wells and the cell proliferation scored 6 days later. RrSCF synergized with IL-3, IL-6, and G-CSF to stimulate the proliferation of single cells. The cells in positive wells were subcultured into colony-forming assays and up to 400 CFC per well were obtained after 14 days incubation of the secondary cultures. These data demonstrate that rrSCF acts in combination with various growth factors to directly stimulate the amplification potential of hematopoietic primitive precursors, resulting in differentiation of these precursors.
Synergistic induction of plasminogen activator inhibitor type-1 in HEP G2 cells by thrombin and transforming growth factor-beta
Authors: Hopkins WE , Fujii S , Sobel BE
Published: October 2019

Plasminogen activator inhibitor type-1 (PAI-1) is a physiologic modulator of the fibrinolytic system. Its activity in plasma increases in diverse thrombotic states. The large synthetic capacity of the liver make it a source of potentially large amounts of PAI-1. Because thrombin activity increases in association with thrombotic disorders and because specific binding sites for thrombin have been identified on hepatocytes, we characterized the effect of thrombin on hepatocyte PAI- 1 production. Incubation of Hep G2 cells with human alpha-thrombin resulted in a dose- and time-dependent increase in the concentration of PAI-1 in conditioned media. This effect was inhibited completely by hirudin and by antithrombin III. Steady-state levels of both the 3.2-kb and 2.2-kb forms of PAI-1 mRNA increased after stimulation of the cells with thrombin, indicating that thrombin influences PAI-1 expression in Hep G2 cells at the pretranslational level. Incubation of Hep G2 cells with alpha-thrombin and either platelet lysates or purified transforming growth factor-beta (TGF-beta), both previously shown to augment hepatocyte PAI-1 expression, resulted in a synergistic increase in the concentration of PAI-1 in conditioned media. PAI-1 mRNA appeared to be synergistically increased as well. Thus, thrombin increases expression of both PAI-1 protein and mRNA in Hep G2 cells and exerts synergistic effects with TGF-beta. These results underscore the potential importance of inhibition of thrombin under conditions in which thrombolysis is induced pharmacologically.
Regulation of glycoprotein IIB/IIIA exposure on platelets stimulated with alpha-thrombin
Authors: van Willigen G , Akkerman JW
Published: October 2019

Previous studies have shown that binding sites for fibrinogen on platelets stimulated with platelet-activating factor (PAF), adenosine diphosphate or epinephrine rapidly close in the absence of fibrinogen. In the present study we investigated whether alpha-thrombin induced similar changes in the glycoprotein (GP) IIB/IIIA-complex. Whereas 80% of binding sites exposed by PAF closed within 30 minutes (22 degrees C), alpha-thrombin (0.1 U/mL) triggered long-lasting exposure of binding sites for [125I]-fibrinogen and [125I]-fibronectin. Even removal of alpha-thrombin with an excess of hirudin failed to close the binding sites. Similar to PAF, alpha-thrombin-exposed sites rapidly closed after addition of the protein kinase C inhibitor staurosporine (1 mumol/L) or dibutyryl cyclic adenosine monophosphate (250 mumol/L). In contrast, prostacyclin (PGI2, 10 ng/mL), which induced rapid closure of binding sites in platelets stimulated with PAF, failed to close the sites in alpha-thrombin-treated platelets. Removal of alpha-thrombin from the platelets restored the PGI2-sensitivity. These data indicate that a short interaction between alpha-thrombin and platelets triggers long-lasting exposure of GPIIB/IIIA. Furthermore, as long as alpha- thrombin remains bound to the platelets, agonists that activate the PGI2-receptor are unable to close GPIIB/IIIA.
Platelet activation and subsequent inhibition by plasmin and recombinant tissue-type plasminogen activator
Authors: Penny WF , Ware JA
Published: October 2019

The success of plasminogen activators in recanalizing occluded coronary arteries may be influenced by their effect on blood platelets; however, some previous studies have shown platelet activation by plasmin and thrombolytic agents while others have shown an inhibitory effect. Moreover, it has not been determined whether these effects reflect an alteration of intracellular signal transduction, fibrinogenolysis, degradation of adhesive protein receptors, or a combination of these events. To distinguish among these possibilities, the increase of cytoplasmic [Ca2+] [( Ca2+]i), which is an intracellular marker of platelet activation that precedes fibrinogen binding to the surface of activated platelets, was measured along with aggregation and release of 5-hydroxytryptamine (5-HT) in washed human platelets incubated with plasmin or recombinant tissue-type plasminogen activator (rt-PA). Plasmin (0.1 to 1.0 CU/mL) induced a prompt, concentration-dependent [Ca2+]i increase when added to platelets, but subsequently inhibited the [Ca2+]i increase in response to thrombin or the endoperoxide analog U44069. Platelet aggregation accompanied the [Ca2+]i increase if the platelets were stirred, while the aggregation of platelets unstirred during plasmin incubation was inhibited upon agonist addition and resumption of stirring. The release of 5-HT paralleled the [Ca2+]i increase induced by plasmin and was also inhibited after the subsequent addition of a second agonist. The effects of rt-PA, added with plasminogen (100 micrograms/mL), were similar to those of plasmin, and could be accounted for by the concentration of plasmin generated. The ADP scavengers apyrase and CP/CK each prevented the [Ca2+]i increase, and aggregation caused by plasmin or rt-PA, and also prevented their inhibitory effects on thrombin-induced activation. Thus, plasmin and rt- PA initially activate platelets, inducing a [Ca2+]i increase, and, if the platelets are stirred, aggregation. Such activation is followed by subsequent inhibition of cellular activation by a second agonist; the inhibitory effect is in proportion to the degree of initial activation, and ADP is an important cofactor in both processes. These platelet effects occur at rt-PA concentrations achievable clinically, and may affect the success of therapy with thrombolytic and adjunctive agents.
Patterns of Epstein-Barr virus infection in non-neoplastic lymphoid tissue
Authors: Niedobitek G , Herbst H , Young LS , Brooks L , Masucci MG , Crocker J , Rickinson AB , Stein H
Published: October 2019

Taking advantage of the abundant expression of the small Epstein-Barr virus (EBV)-encoded RNAs (EBERs) in latently infected cells, we have analyzed 72 normal and hyperplastic lymph nodes and three tonsils of acute infectious mononucleosis (IM) for the presence and distribution of EBV+ cells using EBER-specific in situ hybridization, in some cases combined with immunohistologic demonstration of cell type- characteristic antigens. In IM, large numbers of EBV+ lymphoid B blasts were detectable in extrafollicular areas, whereas germinal centers were generally free of EBV+ cells. In reactive lymph nodes, the frequency of EBV+ cells varied with the degree of lymphoid hyperplasia and underlying immune status. The lowest numbers of EBV+ cells were detected in nonactivated lymph nodes and highest in human immunodeficiency virus-associated lymphadenopathy. If present in these lymph nodes, EBV+ cells were almost exclusively localized to extrafollicular areas, as also observed in IM. However, in contrast to IM, these cells were mainly small lymphocytes. Furthermore, in some instances, occasional scattered EBV+ cells were seen within germinal centers, and in two cases diffuse expansions of EBV+ cells occurred within a single germinal center each, indicating that under certain circumstances EBV+ B lymphocytes may participate in physiologic germinal center reactions. These findings reflect the interference of EBV with physiologic lymphoid differentiation pathways and provide a link to EBV-associated malignant lymphomas with a postulated origin from germinal center cells.
Phase I trial of an interleukin-2 (IL-2) fusion toxin (DAB486IL-2) in hematologic malignancies expressing the IL-2 receptor
Authors: LeMaistre CF , Meneghetti C , Rosenblum M , Reuben J , Parker K , Shaw J , Deisseroth A , Woodworth T , Parkinson DR
Published: October 2019

DAB486IL-2 is a recombinant fusion toxin in which the native receptor binding domain of diphtheria toxin has been replaced with human interleukin-2 (IL-2). It selectively binds and intoxicates only cells that bear the high-affinity receptor for IL-2. In the first clinical trial of a genetically engineered ligand fusion-toxin, we have treated 18 patients with chemotherapy-resistant IL-2 receptor expressing hematologic malignancies with escalating doses of DAB486IL-2. The maximal tolerated dose of a daily intravenous bolus of DAB486IL-2 was 0.1 mg/kg per day for 10 doses, established by asymptomatic, reversible elevations of hepatic transaminases without changes in other tests of liver function. Other mild reversible side effects noted were rash, nausea, elevated creatinine, chest tightness, and fever. Pharmacokinetic analysis showed a monophasic clearance of 5.8 +/- 0.7 minutes with peak levels of 3,549 +/- 1,041 mg/mL at the 0.1 mg/kg dose. Approximately 50% of patients developed an antibody response to diphtheria toxin or DAB486IL-2. The presence of such antibodies did not preclude patients from experiencing an antitumor response as four of the six patients with antitumor effect had detectable antibody titers. Although this was a phase I trial designed to define the safety of DAB486IL-2, remissions were observed in three patients lasting from 5 to over 18 months. The ability to achieve significant tumor reductions in this group of heavily treated patients is encouraging and suggests additional trials are warranted in hematologic malignancies.
Decreased expression of eosinophil peroxidase and major basic protein messenger RNAs during eosinophil maturation
Authors: Gruart V , Truong MJ , Plumas J , Zandecki M , Kusnierz JP , Prin L , Vinatier D , Capron A , Capron M
Published: October 2019

We evaluated the levels of mRNAs encoding cationic proteins in peripheral blood eosinophils (PBE) purified from patients with eosinophilia and in eosinophils differentiated from cord blood cells (CBC) by culture with recombinant human interleukin-3 (rhIL-3), rhGM- CSF, and rhIL-5. Messenger RNAs encoding eosinophil peroxidase (EPO), major basic protein (MBP), eosinophil-derived neurotoxin (EDN), and eosinophil cationic protein (ECP) were detected by Northern blot hybridization with the respective specific oligonucleotide probes. In mature PBE, MBP mRNA appeared to be absent, whereas EPO mRNA was barely detectable in only 5 of the 19 patients. In contrast, EDN and ECP mRNAs were observed in the PBE of all patients. In CE, EPO, and MBP, mRNAs were abundant in immature eosinophils and their amounts decreased after differentiation toward eosinophils. ECP and EDN mRNAs followed the same patterns, but mRNAs were less abundant at all timepoints studied. Study of mRNA t1/2 during the time course of differentiation indicated that changes in the stability of the different mRNAs were not responsible for the variations observed in the steady-state levels. Together, these results suggest that regulation of expression differs among EPO, MBP, EDN, and ECP mRNAs during the time course of eosinophil differentiation.
Long-term generation of colony-forming cells in liquid culture of CD34+ cord blood cells in the presence of recombinant human stem cell factor
Authors: Migliaccio G , Migliaccio AR , Druzin ML , Giardina PJ , Zsebo KM , Adamson JW
Published: October 2019

Human cord blood was used as a source of progenitor and stem cells to evaluate the effect of recombinant human stem-cell factor (SCF) on colony formation and the generation of colony-forming cells (CFC) under highly defined, serum-deprived conditions. SCF interacted with a number of hematopoietic growth factors to stimulate colony growth and was particularly effective in stimulating the formation of mixed-cell colonies from CD34+ soybean agglutinin negative (SBA-) cells. In suspension culture of CD34+, SBA- cells, SCF alone was unable to maintain cell numbers or CFC but, in combination with interleukin-3 (IL- 3), increased input numbers of cells by 10-fold and increased CFC of all kinds by nearly 20-fold. This included erythroid burst-forming cells (BFU-E), granulocyte/macrophage (GM) CFC, and mixed-cell CFC. In contrast, CD34- SBA- cells neither gave rise to CFC nor were maintained by combinations of growth factors including SCF. SCF interacted with erythropoietin (Epo) and granulocyte colony-stimulating factor (G-CSF) to maintain large numbers of cells as well as to generate a twofold to threefold increase in CFC in the case of Epo, and a 10-fold increase in CFC in the case of G-CSF. With Epo, the predominant CFC generated were BFU-E and erythroid CFC and many of the cells in suspension were erythroblasts. In contrast, SCF plus G-CSF resulted in large numbers of granulocytes at various stages of maturation and the CFC generated were almost exclusively granulocytic-CFC. IL-1 and IL-6, alone or in combination with SCF, showed little or no ability to increase cell numbers or generate CFC. In summary, SCF interacts with a variety of hematopoietic growth factors to promote colony formation, particularly mixed-cell colony formation, and also, in suspension culture, SCF interacts with IL-3, G-CSF, and Epo to generate large numbers of differentiated cells as well as a variety of CFC for up to 1 month.
Characterization of the gamma chain platelet binding site on fibrinogen fragment D
Authors: Kirschbaum NE , Mosesson MW , Amrani DL
Published: October 2019

Glycoprotein (GP) IIb/IIIa on adenosine diphosphate (ADP)-activated human platelets interacts with specific sites on the fibrinogen molecule leading to aggregation. We characterized the platelet-binding site on the gamma chains of fibrinogen using plasmic fragments D gamma A and D gamma'. Fragment D gamma A, which contains the carboxy terminal gamma A400–411 platelet-binding sequence (HHLGGAKQAGDV), was 70-fold more active than the synthetic gamma A400–411 peptide in inhibiting ADP- induced platelet aggregation. Fragment D gamma A inhibited fibrinogen binding and also bound directly to ADP-activated platelets. The Kd values determined for fibrinogen and fragment D gamma A binding were 0.55 mumol/L and 1.2 mumol/L, respectively. In contrast, fragment D gamma', which differs from fragment D gamma A with respect to its gamma chain sequence from position 408 to the COOH-terminus at position 427, did not inhibit platelet aggregation or fibrinogen binding, and did not bind directly to the platelet surface. Denaturation of fragment D gamma A with guanidine-HCl caused a loss of inhibitory activity in platelet aggregation assays. These data indicate that the native conformation of the gamma chain platelet-binding site on fibrinogen is important for optimal binding to GPIIb/IIIa.
In vivo efficacy of B43 (anti-CD19)-pokeweed antiviral protein immunotoxin against BCL-1 murine B-cell leukemia
Authors: Uckun FM , Chelstrom LM , Irvin JD , Finnegan D , Gunther R , Young J , Kuebelbeck V , Myers DE , Houston LL
Published: October 2019

We show that a highly aggressive subclone of murine BCL-1 B-lineage leukemia expresses a single 2.4-kb transcript hybridizing to the human CD19 cDNA probe and reacts strongly with the anti-human CD19 monoclonal antibodies (MoAb) B43, B4, Leu-12, and J3–119. In contrast to their strong reactivity with anti-human CD19 MoAb, BCL-1 cells show no reactivity with MoAb directed against human CD22, CD72, HLA-DR, IgD, or IgM. Western blot analysis of BCL-1 whole cell lysates with the anti- human CD19 MoAb J3–119 showed a single 69-Kd protein band, which was not detected by the negative control MoAb G19.4 (anti-CD3). In contrast to BCL-1 cells, normal BALB/c splenocytes or mouse splenocyte/myeloma hybridoma cell lines did not (1) express any transcripts that hybridized to the human CD19 cDNA probe, (2) react with B43/anti-CD19 MoAb, or (3) express the 69-Kd protein that reacts with the anti-human CD19 MoAb J3–119. Murine BCL-1 B-cell leukemia thus provides a unique model of disseminated B-lineage leukemia to evaluate the antileukemic efficacy of anti-CD19 immunotoxins. This model was subsequently used to evaluate the in vivo homing ability, pharmacokinetics, and antileukemic efficacy of B43 MoAb conjugated to the plant hemitoxin pokeweed antiviral protein (PAP). B43-PAP immunotoxin (1) showed strong and antigen-specific reactivity with BCL-1 cells, (2) promptly penetrated the spleens of leukemic mice, (3) rapidly reduced the BCL-1 leukemia burden of leukemic mice and, most importantly, (4) improved survival. Finally, B43-PAP immunotoxin was more effective against BCL-1 leukemia than 700 cGy (LD100/30) total body irradiation (TBI) followed by syngeneic bone marrow transplantation (BMT).
Effect of nerve growth factor on the release of inflammatory mediators by mature human basophils
Authors: Bischoff SC , Dahinden CA
Published: October 2019

Nerve growth factor (NGF) is a neurotrophic cytokine known to regulate the survival and function of peripheral and central neuronal cells. Recently, the spectrum of action could be extended to non-neuronal cell types such as rat mast cells and human B lymphocytes. The present study shows that NGF affects the function of mature human basophils isolated from the peripheral blood of healthy donors. Both murine NGF 7S and recombinant human NGF beta enhance histamine release and strongly modulate the formation of lipid mediators by basophils in response to various stimuli. This priming effect of NGF on basophils occurs rapidly within 10 to 15 minutes of preincubation, is dose-dependent, and requires similarly low concentrations (1 to 40 pmol/L) of human NGF beta as the induction of neurite outgrowth in ganglion cells. Cell fractionation studies indicate that NGF acts directly on human basophils without an involvement of other cell types, suggesting the presence of high-affinity NGF receptors on basophils. NGF by itself (up to 4 nmol/L of human NGF beta) does not induce the release of inflammatory mediators directly. The effect of human NGF on basophil mediator release is similar to that of the hematopoietic growth factors interleukin-3, interleukin-5, and granulocyte-macrophage colony- stimulating factor. The present study further demonstrates that NGF acts as a pleiotropic cytokine at the interface between the nervous and the immune system, and that NGF may be involved in inflammatory processes and hypersensitivity reactions.
Reduction of tissue iron stores and normalization of serum ferritin during treatment with the oral iron chelator L1 in thalassemia intermedia
Authors: Olivieri NF , Koren G , Matsui D , Liu PP , Blendis L , Cameron R , McClelland RA , Templeton DM
Published: October 2019

In patients with thalassemia intermedia in whom hyperabsorption of iron may result in serious organ dysfunction, an orally effective iron- chelating drug would have major therapeutic advantages, especially for the many patients with thalassemia intermedia in the Third World. We report reduction in tissue iron stores and normalization of serum ferritin concentration after 9-month therapy with the oral chelator 1,2- dimethyl-3-hydroxypyrid-4-one (L1) in a 29-year-old man with thalassemia intermedia and clinically significant iron overload (SF 2,174 micrograms/L, transferrin saturation 100%; elevated AST and ALT, abnormal cardiac radionuclide angiogram) who was enrolled in the study with L1 75 mg/kg/day after he refused deferoxamine therapy. L1-Induced 24-hour urinary iron excretion during the first 6 months of therapy was (mean +/- SD, range) 53 +/- 30 (11 to 109) mg (0.77 mg/kg), declining during the last 3 months of L1 to 24 +/- 14 (13–40) mg (0.36 mg/kg), as serum ferritin decreased steadily to normal range (present value, 251 micrograms/L). Dramatic improvement in signal intensity of the liver and mild improvement in that of the heart was shown by comparison of T1- weighted spin echo magnetic resonance imaging with images obtained immediately before L1 administration was observed after 9 months of L1 therapy. Hepatic iron concentration decreased from 14.6 mg/g dry weight of liver before L1 therapy to 1.9 mg/g liver after 9 months of therapy. This constitutes the first report of normalization of serum ferritin concentration in parallel with demonstrated reduction in tissue iron stores as a result of treatment with L1. Use of L1 as a therapeutic option in patients with thalassemia intermedia and iron overload appears warranted.
Should HLA-identical sibling bone marrow transplants for leukemia be restricted to large centers? [see comments]
Authors: Horowitz MM , Przepiorka D , Champlin RE , Gale RP , Gratwohl A , Herzig RH , Prentice HG , Rimm AA , Ringden O , Bortin MM
Published: October 2019

There is substantial evidence that the volume of medical procedures in a hospital has an inverse relationship with mortality. We analyzed data for 1313 recipients of HLA-identical sibling bone marrow transplants for early leukemia (acute leukemia in first remission or chronic myelogenous leukemia in first chronic phase) to determine whether transplant outcome differed in small and large centers. Transplants were performed in 86 bone marrow transplant centers active between the years 1983 and 1988, which participated in the International Bone Marrow Transplant Registry. Twenty-one (24%) centers performed five or fewer allogeneic transplants per year during the study period; five (6%) performed more than 40 per year. After adjustment for differences in patient and disease characteristics, the relative risks of treatment- related mortality (1.53, P less than .01) and treatment failure (1.38, P less than .04) were higher among patients who received transplants at centers doing five or fewer transplants per year than among those at larger centers. Among patients receiving transplants in centers performing more than five transplants a year, there was no statistically significant correlation between number of transplants and outcome.
Acetylcholinesterase in murine erythroleukemia (Friend) cells: evidence for megakaryocyte-like expression and potential growth-regulatory role of enzyme activity
Authors: Paoletti F , Mocali A , Vannucchi AM
Published: October 2019

Features of true acetylcholinesterase (AChE) regulation during growth and differentiation of Friend murine erythroleukemia cells (MELC) have been investigated with respect to other erythroid and nonerythroid murine elements. Enzyme levels of uninduced MELC were in between the very low AChE contents of erythroid cells and the huge amounts of activity exhibited by megakaryocytes and platelets. After MELC commitment to terminal division, the enzyme-specific activity increased largely, approaching values that were much closer to those of thrombocytic than of normal erythroid elements. The bulk of AChE activity in MELC, megakaryocytes, and platelets was found to be located in the cytosol as a free-soluble form. Moreover, during incubation, MELC actively released large amounts of AChE into the medium, like it occurs in murine thrombocytes. Conversely, the enzyme of the erythroid elements was mainly associated with the membranes and was not released extracellularly. Experiments with inducers showed that changes in AChE- specific activity of MELC correlated directly with the arrest of cell proliferation rather than with the activation of differentiated erythroid functions. The inverse relationship existing between MELC growth rates and AChE levels was further supported by the relative enzyme activities of the slow- and fast-growing subclones. We conclude that uninduced MELC potentially share properties of both the erythroid and megakaryoblastic phenotype. The latter might be revealed by typical regulation of AChE activity according to a thrombocytic-like program activated upon MELC commitment to terminal division. Eventually, the inhibition of MELC growth by exogenous pure bovine AChE suggested that the secreted murine enzyme might serve as a potential negative signal of cellular replication.
Characterization of urokinase receptor expression by human placental trophoblasts
Authors: Zini JM , Murray SC , Graham CH , Lala PK , Kariko K , Barnathan ES , Mazar A , Henkin J , Cines DB , McCrae KR
Published: October 2019

The processes of implantation and placentation are both dependent on the invasion and remodeling of the uterine endometrium and vasculature by trophoblasts. Because the secretion and autocrine binding of urokinase (uPA) appears to be a common mechanism used by cells to facilitate plasmin-dependent tissue invasion, we measured the production of uPA and expression of uPA receptors by trophoblasts. Prourokinase bound specifically, reversibly, and with high affinity to cultured trophoblasts, via the uPA epidermal growth factor-like domain. Trophoblasts derived from two first-trimester placentae bound more prourokinase than cells isolated from term placentae. Furthermore, in vitro differentiation of cultured cytotrophoblasts into syncytiotrophoblasts was associated with diminished expression of urokinase receptors and a parallel decrease in the cellular content of uPA receptor mRNA. Trophoblasts also secreted prourokinase and plasminogen activator inhibitors types 1 and 2 (PAI-1 and PAI-2). Although prourokinase was secreted in amounts sufficient to endogenously saturate trophoblast uPA receptors, trophoblasts secreted greater amounts of PAI-1 and PAI-2 than uPA, and no net plasminogen activator activity was detected in trophoblast conditioned medium. In contrast, plasminogen added directly to cultured trophoblasts was readily converted to plasmin. Although the invasion and remodeling of uterine tissues by trophoblasts is a complex process dependent on several proteases of varying specificity, our findings suggest that the expression and modulation of urokinase receptors on the trophoblast cell surface may play an important role in this process.
Origin of anti-idiotypic activity against anti-factor VIII autoantibodies in pools of normal human immunoglobulin G (IVIg)
Authors: Dietrich G , Algiman M , Sultan Y , Nydegger UE , Kazatchkine MD
Published: October 2019

Therapeutic preparations of polyspecific IgG obtained from plasma pools of a large number of normal donors (IVIg) express anti-idiotypic activity against a wide spectrum of natural and disease-associated autoantibodies. The present study investigated the origin of anti- idiotypic activity against autoantibodies to factor VIII. The neutralizing activity of pools of IgG against patients' anti-factor VIII autoantibodies was not influenced by the presence of individuals with natural anti-factor VIII antibodies among donors contributing to the pool. A higher frequency of neutralizing antibodies against anti- factor VIII autoantibodies was found in aged donors as compared with young adults and in pools of IgG from multiparous women as compared with IgG from random donors. Pooling IgG from several donors synergistically enhanced the inhibitory activity of the pools. Thus, a neutralizing activity against anti-factor VIII autoantibodies was detected in pools of IgG of as few as two to four donors of whom individually tested IgG did not exhibit inhibitory activity against anti-factor VIII autoantibodies. These observations suggest that aged donors and multiparous women may be privileged sources for the anti- idiotypic activity of IVIg against autoantibodies and emphasize that the expression of anti-idiotypic activity in IVIg results from a synergistic participation of anti-idiotypes from each donor contributing to the pool.
Regulation of complement functional efficiency by histidine-rich glycoprotein
Authors: Chang NS , Leu RW , Rummage JA , Anderson JK , Mole JE
Published: October 2019

The modulation of complement functional efficiency by serum histidine- rich glycoprotein (HRG) was investigated. Addition of exogenous HRG to prewarmed diluted serum, followed immediately by sensitized sheep erythrocytes (EA), resulted in enhanced hemolysis. However, when HRG was incubated with diluted serum for 10 minutes at 37 degrees C, inhibition of hemolysis occurred. The biphasic modulation of complement function was also obtained with the complement alternative pathway when HRG was added to diluted serum for hemolysis of rabbit erythrocytes. Partial reduction of complement functional activity was shown when serum was absorbed by an HRG-Sepharose 6MB column. Western blot analysis showed that complement C8, C9, factor D, and S-protein in diluted serum were bound by nylon membrane-immobilized HRG. However, by immunoprecipitation of relatively undiluted serum with anti-HRG IgG beads, HRG was found to coprecipitate with S-protein and plasminogen, which suggested that HRG may complex with these proteins in serum. In functional tests, HRG inhibited C8 hemolytic activity, probably by preventing C8 binding to EAC1–7 cells. HRG also enhanced polymerization of purified C9 as well as the generation of a 45-Kd C9 fragment. Such an effect was even more pronounced in the presence of divalent cations with the reaction mixtures of C9 and HRG. Partial dimerization of C9 was shown when exogenous HRG was added to normal serum. In contrast, polymerization of serum C9 was inhibited by exogenous HRG during poly I:C activation of serum or incubation under low ionic strength conditions. HRG was further shown to inhibit factor D-mediated cleavage of factor B when bound by cobra venom factor. The molecular basis by which HRG regulates serum complement function is not clear. Hypothetically, the tandem repetitions of a consensus histidine-rich penta-peptide sequence in HRG may provide a highly charged area that interacts with complement components.
The translocation (6;9) (p23;q34) shows consistent rearrangement of two genes and defines a myeloproliferative disorder with specific clinical features
Authors: Soekarman D , von Lindern M , Daenen S , de Jong B , Fonatsch C , Heinze B , Bartram C , Hagemeijer A , Grosveld G
Published: October 2019

Translocation (6;9)(p23;q34) is a cytogenetic aberration that can be found in specific subtypes of both acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). This translocation is associated with an unfavourable prognosis. Recently, the genes involved in the t(6;9) were isolated and characterized. Breakpoints in both the dek gene on chromosome 6 and the can gene on chromosome 9 appear to occur in defined regions, which allows us to diagnose this type of leukemia at the molecular level. Moreover, because of the translocation a chimeric dek-can mRNA is formed which, as we show here, is an additional target for diagnosis via cDNA-preparation and the polymerase chain reaction (PCR). We studied 17 patients whose blood cells and/or bone marrow cells showed a t(6;9) with karyotypic analysis. Fourteen patients suffered from AML, one patient had a refractory anemia with excess of blasts in transformation (RAEBt), one patient had an acute myelofibrosis (AMF), and one patient a chronic myeloid leukemia (CML). In nine cases studies at the DNA and RNA levels were possible while in seven cases only the DNA could be analyzed. In one case only RNA was available. Conventional Southern blot analysis showed the presence of rearrangements of both the dek gene and the can gene. In both genes, breakpoints cluster in one intron in the patients investigated. The presence of a consistent chimeric dek-can product after cDNA preparation followed by the PCR was demonstrated. We conclude from our data that the t(6;9) is found in myeloproliferative disorders with typical clinical characteristics. This translocation results in highly consistent abnormalities at the molecular level.
Complement activation during storage of blood under normal blood bank conditions. Effects of proteinase inhibitors and leukocyte depletion
Authors: Schleuning M , Schmid-Haslbeck M , Utz H , Jochum M , Heim M , Mempel W , Wilmanns W
Published: October 2019

During storage of CPD-A1 preserved whole blood factors of the complement cascade become activated, as evidenced by a rapid increase in the concentrations of C3a-desArg and C4a-desArg. After 10 to 14 days of whole blood storage, the elevations of C3a and C4a levels were highly significant. This increase was paralleled by an increase in the concentration of the lysosomal proteinase elastase from polymorphonuclear (PMN) granulocytes. By contrast, the concentration of the C3 activator complex C4b2b remained unchanged even after 3 weeks of storage. The supplementation of the anticoagulant CPD-A1 with the polyvalent-proteinase-inhibitor aprotinin and the specific elastase- inhibitor eglin C failed to inhibit complement activation, whereas leukocyte depletion could partially abolish the increase of the concentration of C4a, but had no effect on C3a concentrations. These observations support the notion that cleavage of C4 during storage of whole blood is partially leukocyte dependent, whereas the activation of C3 is possibly caused by the activation of the alternate pathway of the complement system by contact of plasma with plastic surfaces.