Biological activities of a human pluripotent hemopoietic colony stimulating factor on normal and leukemic cells

Comparative effects of a recombinant and a mutein type of granulocyte colony stimulating factor on the growth of Meth-A fibrosarcoma with 5-fluorouracil chemotherapy

The present study was designed to evaluate the effects of a recombinant human G-CSF (rhG-CSF) and a mutein G-CSF (KW-2228) on leucopenia and tumor growth in mice treated with 5-fluorouracil (5-FU). In normal mice, the number of leucocytes (white blood cell, WBC) reached the peak 12 hours after a single injection of either type of G-CSF and decreased to the normal level after 24 hours. Daily administration induced a continuous increase in the WBC count, however, administrations at intervals did not. Meth-A fibrosarcoma was subcutaneously inoculated into the backs of syngeneic BALB/c mice. The mice were treated with 5-FU alone or with G-CSFs. Chemotherapy with 5-FU alone resulted in leucopenia and an insignificant inhibition of tumor growth. The conjunctive administration of G-CSFs with 5-FU resulted in a significantly augmented inhibition of tumour growth, and leukopenia was not seen. This augmenting effect was more prominent with KW-2228. These results suggest that in 5-FU chemotherapy G-CSFs may be beneficial in restoring the number of leucocytes from leucopenic state and in augmenting the tumor inhibitory effect. Furthermore, KW-2228 may be more beneficial than the natural type rhG-CSF.

Granulocyte colony-stimulating factor does not enhance endotoxin-induced acute lung injury in guinea pigs

We studied recombinant human granulocyte colony-stimulating factor (G-CSF) in terms of its hematopoietic and neutrophil-activating effects on acute lung injury induced by endotoxin. Guinea pigs were divided into four groups: (1) saline control animals, (2) endotoxin alone, (3) cyclophosphamide (CPA)+endotoxin, and (4) G-CSF+endotoxin. A G-CSF dose of 20 micrograms/kg was given subcutaneously twice a day for 5 days. Animals were observed for 4 h after intravenously administered endotoxin (0.02 and 2.0 mg/kg) with serial measurements of complete blood counts and hemodynamics. Lung extravascular water, [125I]albumin leakage in lung tissue, and histopathologic features were examined at death. The endotoxin-alone group showed peripheral leukopenia, transient hypotension, excess lung water, increased albumin leakage, PMN accumulation in lung tissue, and gross histopathologic edema. G-CSF-treated animals showed attenuated responses in peripheral leukopenia, excess lung water, and albumin leakage in comparison with the endotoxin-alone group. No augmented responses were seen in the G-CSF group. The CPA+endotoxin group also had attenuated lung injury, which was similar to that in the G-CSF group. In conclusion, pretreatment with G-CSF tended to attenuate rather than enhance neutrophil-dependent acute lung responses to endotoxin.

Effect of recombinant human granulocyte colony-stimulating factor in patients receiving chemotherapy for urogenital cancer. Urological rhG-CSF Study Group

We evaluated the efficacy and safety of recombinant human granulocyte colony-stimulating factor (G-CSF) in patients with leukopenia after chemotherapy for urogenital cancers. Recombinant human G-CSF was administered at 100 micrograms./m.2 intravenously in 36 patients and at 75 micrograms. per body weight subcutaneously in 37 for 8 days after methotrexate, vinblastine, doxorubicin and cisplatin (M-VAC) therapy or for 14 days after other chemotherapies. Cycle 1 of chemotherapy was given without recombinant human G-CSF, while at cycle 2, recombinant human G-CSF was given additionally. Therefore, cycle 1 of the regimen served as a control to cycle 2 in each patient. An elevation in the median white blood cell nadir was noted: 1,500 versus 3,200 (intravenous) and 2,100 versus 3,200 (subcutaneous) on M-VAC therapy, and 1,800 versus 2,100 (intravenous) and 1,700 versus 2,500 (subcutaneous) on other chemotherapeutic regimens. A shortening of the leukopenic period was observed in cycle 2. There were no significant adverse side effects attributed to the use of recombinant human G-CSF. The results indicate that recombinant human G-CSF may be safely and effectively used against leukopenia after chemotherapy for urogenital cancer. This remedy will become useful for completion of the schedule and dose intensification of chemotherapy in the future. Subcutaneous administration is considered to be the more preferable route.

Enhancement of chemotherapeutic effects by recombinant human granulocyte colony-stimulating factor on implanted mouse bladder cancer cells (MBT-2)

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was administered intraperitoneally in combination with multidrug chemotherapy using methotrexate (M), vinblastine (V), doxorubicin (A), and cisplatin (C, or for the combination, MVAC) to C3H/He mice (5-week-old females) after experimental carcinoma, MBT-2, a transplantable transitional cell carcinoma of the urinary bladder had been implanted. The effects of therapy were studied. The animal groups consisted of: (1) control (no drug administration), (2) rhG-CSF (100 micrograms/kg/d, from days 8 through 42 after MBT-2 implantation, except for the days when MVAC was administered), (3) high-dose MVAC (2 mg/kg of M, 0.2 mg/kg of V, 2 mg/kg of A, and 4 mg/kg of C once a week for 3 weeks), (4) low-dose MVAC (one-quarter of the high dose), (5) high-dose MVAC with rhG-CSF, and (6) low-dose MVAC with rhG-CSF. In an in vitro system, rhG-CSF did not show any effect on the proliferation of MBT-2 cells or exert any influences on A's tumor proliferation-suppressing action on MBT-2. However, in an in vivo system, concomitant administration of rhG-CSF significantly enhanced the tumor-suppressing effect of the MVAC therapy, as did rhG-CSF alone. The greatest effect was observed in the group receiving high-dose MVAC plus rhG-CSF. These result suggested that rhG-CSF-stimulated granulocytes may exert antitumor activity on tumor cells severely damaged by chemotherapeutic agents at a relatively high concentration. The survival rate was improved to some degree even by administration of rhG-CSF alone. Although further study is required to elucidate the action mechanism of rhG-CSF, these results suggest that rhG-CSF may be useful clinically to enhance the activity of antitumor agents and not only through its ability to alleviate granulocytopenia or prevent its development.

Use of Recombinant Canine Granulocyte Colony-Stimulating Factor to Decrease Myelosuppression Associated with the Administration of Mitoxantrone in the Dog

Ten dogs were given mitoxantrone at a dose of 5 mg/m2 body surface area intravenously. Recombinant canine granulocyte colony-stimulating factor (rcG-CSF) was administered subcutaneously daily for 20 days after an infusion of mitoxantrone in five of these dogs to determine the effect of the hematopoietic growth factor on the duration and severity of myelosuppression. The median neutrophil counts dropped below normal (less than 3,000/uL) for 2 days in the dogs that received rcG-CSF, and for 5 days in the dogs that received only mitoxantrone. Four of five dogs not treated with rcG-CSF and none of those receiving rcG-CSF developed serious neutropenia (less than 1,500/uL). The neutrophil counts were significantly (P less than 0.05) higher in the rcG-CSF treated dogs at all time points except before the administration of the colony-stimulating factor, and the sixth day after the mitoxantrone was administered. These findings demonstrate that rcG-CSF is capable of reducing the duration and severity of mitoxantrone-induced myelosuppression.

Hematopoietic growth factors in clinical hematology

Five primary hematopoietic growth factors have been extensively evaluated in trials in patients with inadequate blood cell formation. Results have convincingly demonstrated that various chronic anemias can be corrected with erythropoietin. Similarly, there is no doubt that granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony stimulating factor (G-CSF) increase the number of leukocytes and improve the function of cells in patients with congenital and acquired leukopenias. Recent studies indicate that interleukin-3 (IL-3) and macrophage colony-stimulating factor (M-CSF) can also stimulate blood cell production in patients. As a result, morbidity and perhaps mortality associated with severe cytopenias can be reduced substantially.

Recombinant granulocyte colony-stimulating factor (rG-CSF). A review of its pharmacological properties and prospective role in neutropenic conditions

Recombinant granulocyte colony-stimulating factor (rG-CSF) is a glycoprotein hormone which has been produced in mammalian cells and, in a nonglycosylated form, in the bacterium Escherichia coli through recombinant DNA technology. It stimulates proliferation, differentiation and activation of cells of the neutrophil-granulocyte lineage and has been investigated as therapy for patients with various neutropenic conditions, both iatrogenic and disease related. rG-CSF is well tolerated, the most frequently reported adverse effect being mild to moderate bone pain. A major use for rG-CSF therapy will be in ameliorating the neutropenia which follows cytoreductive chemotherapy. rG-CSF accelerates neutrophil recovery after chemotherapy, leading to a reduction in duration of the neutropenic phase. Consequently, infection rate is diminished, as is the associated usage of antibiotics and duration of hospitalisation. The implications are that rG-CSF may allow increased dose intensity and stricter adherence to chemotherapy schedules. The increase in neutrophils produced by rG-CSF renders it a useful treatment for conditions such as congenital, acquired and cyclic neutropenias for which current therapy is not very successful. rG-CSF may be an effective therapy in myelodysplasia, although there is concern about acceleration of the possible rate of conversion of this disease to acute myelogenous leukaemia. It is also likely that rG-CSF will be useful in accelerating the recovery of transplanted bone marrow in patients with leukaemia, lymphoma and solid tumour. Furthermore, there is great potential for expansion of the role of rG-CSF as monotherapy or in combination regimens with other cell factors in various haematological disorders such as aplastic anaemia. In summary, while many aspects of its use remain to be clarified, rG-CSF must be seen as an exciting advance in therapeutics. It should rapidly find an important place as an adjunct to cancer chemotherapy, and also appears to have substantial potential in a number of other neutropenic conditions which are currently difficult to treat.

Reduction by granulocyte colony-stimulating factor of fever and neutropenia induced by chemotherapy in patients with small-cell lung cancer

BACKGROUND

Neutropenia and infection are major dose-limiting side effects of chemotherapy. Previous studies have suggested that recombinant methionyl granulocyte colony-stimulating factor (G-CSF) can reduce chemotherapy-related neutropenia in patients with cancer. We conducted a randomized clinical trial to test this hypothesis and the clinical implications.

METHODS

Patients with small-cell lung cancer were enrolled in a multicenter, randomized, double-blind, placebo-controlled trial of recombinant methionyl G-CSF to study the incidence of infection as manifested by fever with neutropenia (absolute neutrophil count, less than 1.0 x 10(9) per liter, with a temperature greater than or equal to 38.2 degrees C) resulting from up to six cycles of chemotherapy with cyclophosphamide, doxorubicin, and etoposide. The patients were randomly assigned to receive either placebo or G-CSF, with treatment beginning on day 4 and continuing through day 17 of a 21-day cycle.

RESULTS

The safety of the study treatment could be evaluated in 207 of the 211 patients assigned to either drug, and its efficacy in 199. At least one episode of fever with neutropenia occurred in 77 percent of the placebo group, as compared with 40 percent of the G-CSF group (P less than 0.001). Over all cycles of chemotherapy, the median duration of grade IV neutropenia (absolute neutrophil count, less than 0.5 x 10(9) per liter) was six days with placebo as compared with one day with G-CSF. During cycles of blinded treatment, the number of days of treatment with intravenous antibiotics, the number of days of hospitalization, and the incidence of confirmed infections were reduced by approximately 50 percent when G-CSF was given, as compared with placebo. Mild-to-moderate medullary bone pain occurred in 20 percent of the patients receiving G-CSF.

CONCLUSIONS

The use of G-CSF as an adjunct to chemotherapy in patients with small-cell cancer of the lung was well tolerated and led to reductions in the incidence of fever with neutropenia and culture-confirmed infections; in the incidence, duration, and severity of grade IV neutropenia; and in the total number of days of treatment with intravenous antibiotics and days of hospitalization.

The role of cytokines in oncology

The availability of sufficient quantities of recombinant human cytokines and promising preclinical data have led to their introduction into clinical trials. Cytokines have potential as new therapeutic agents in a variety of hematological disorders as well as in solid tumors. Only a few of the still increasing number of these glycoprotein hormones have been studied in humans so far, either as single agents or in combination with chemotherapy and other cytokines. Their clinical effects, beneficial role in supportive care, and use in the treatment of certain cancer patients are reviewed.

Evaluation of recombinant canine granulocyte colony-stimulating factor as an inducer of granulopoiesis. A pilot study

Five healthy young adult dogs were given recombinant canine granulocyte colony-stimulating factor (rcG-CSF) at a dosage of 5 micrograms/kg/day subcutaneously for 4 weeks to evaluate the effect on complete blood cell counts. The mean neutrophil counts +/- standard deviation (SD) increased significantly (P less than 0.01) from 6,537/microliters +/- 1,726 (range, 4,950-9,512/microliters) to 26,330/microliters +/- 7,066 (range, 15,368-35,785/microliters) within 24 hours after the first injection of rcG-CSF. Mean monocyte counts +/- SD were significantly increased (P less than 0.05) from baseline values of 751/microliters +/- 168 (range, 444-891/microliters) to 2,514/microliters +/- 878 (range, 1,740-3,752/microliters) on day 5 of rcG-CSF administration. Mean neutrophil and monocyte counts (+/- SD) continued to increase reaching a maximum of 72,125/microliters +/- 15,073 (range, 50,915-96,278/microliters) and 3,972/microliters +/- 2,621 (range, 685-8,030/microliters), respectively by day 19. These increased neutrophil and monocyte counts were maintained until the administration of rcG-CSF was stopped. Blood counts returned to normal within 5 days after discontinuing the rcG-CSF. One week after discontinuing treatment, rcG-CSF was started again at 5 micrograms/kg/day subcutaneously. Within 48 hours following administration of rcG-CSF, mean neutrophil counts +/- SD increased from 5,860/microliters +/- 1,819 (range, 3,720-8,650/microliters) to 57,444/microliters +/- 8,173 (range, 43,983-68,278/microliters). Myeloid:erythroid ratios increased from a mean of 1.63:1 on day 1 prior to administration of rcG-CSF to 3.3:1 on day 10 in three dogs for which bone marrow samples were evaluated. Recombinant canine G-CSF did not cause clinically significant toxicosis in any of the dogs.

Spontaneous release of granulocyte colony-stimulating factor (G-CSF) by alveolar macrophages in the course of bacterial pneumonia and sarcoidosis: endotoxin-dependent and endotoxin-independent G-CSF release by cells recovered by bronchoalveolar lavage

Because granulocyte colony-stimulating factor (G-CSF) is known to induce granulopoiesis and activate mature neutrophils, this factor could be important in determining the number and functional activity of neutrophils at sites of lung disease. The purpose of this study was to evaluate the ability of lung immune and inflammatory cells to produce G-CSF, and to seek evidence for the spontaneous production of this factor by cells recovered by lavage from controls and patients with lung diseases in which neutrophils may play a pathogenetic role. Lavage cells from controls produced little G-CSF spontaneously. Alveolar macrophages (AM), but not lymphocytes, produced large amounts following endotoxin stimulation. Lavage cells from patients with respiratory failure associated with bacterial pneumonia, but not those with respiratory failure from noninfectious causes, spontaneously released G-CSF (32 +/- 24 and less than 1 U/10(6) AM, respectively). Lavage cells from five of 15 patients with sarcoidosis and one of five patients with diffuse pulmonary fibrosis also spontaneously released G-CSF, which could not be explained by endotoxin exposure. The release of G-CSF by endotoxin-dependent and -independent mechanisms could play a role in the recruitment and activation of neutrophils in bacterial pneumonia and participate in the pathogenesis of some interstitial lung diseases.

Hematopoietic colony-stimulating factors

In summary, hematopoietic growth factors have been discovered, biochemically characterized, cloned, produced by recombinant DNA technology, and put into clinical use in a period of 25 years. We are approaching a greater understanding of the cellular anatomy and molecular mechanisms that regulate production of the CSFs, the ways in which the CSFs interact with their cell surface receptors and trigger their biological effects, the nature of these receptors themselves and their mechanisms of signal transduction, and the effects of the CSFs in vitro and in vivo on hematopoietic progenitor cells and mature leukocytes. However, many questions remain. What is the mechanism that couples growth-factor binding to the triggering of cellular proliferation? How do multi-CSF and GM-CSF cross-compete at the level of the cell-surface receptor, and yet show no primary amino acid sequence homology? What are the mechanisms that regulate the tissue expression profile of multi-CSF compared to the genetically similar growth factor GM-CSF? And, what are the optimal dosages, schedules of administration, and combinations of CSFs optimal for each of several conditions of marrow failure? These are but a few of the questions that continue to occupy much current research interest.

Hematopoietic growth factors in cancer

The family of colony stimulating factors and interleukins influence all aspects of hematopoietic cell proliferation and differentiation. In most instances these hematopoietic growth factors have overlapping, pleiotropic effects and frequently regulate early progenitor cell proliferation and mature cell function. Currently, seven of these factors are in clinical trial: erythropoietin for treatment of anephric anemia, IL-2 in conjunction with LAC therapy, and IL-1, IL-3, G-CSF, GM-CSF, and M-CSF for stimulation of myelopoiesis and granulocyte-macrophage function after chemotherapy, irradiation, or bone marrow transplantation in patients with cancer. G-CSF and GM-CSF have also proved effective in treatment of congenital and idiopathic neutropenias and have had some efficacy in treatment of myeloid leukemias, myelodysplastic disorders, aplastic anemia, and acquired immunodeficiency syndrome (AIDS).

Hematopoietic growth factors. Biology and clinical applications

The hematopoietic growth factors are potent regulators of blood-cell proliferation and development. The first phase of clinical trials suggests that they may augment hematopoiesis in a number of different conditions of primary and secondary bone marrow dysfunction. Future clinical use is likely to include combinations of these growth factors, in order to stimulate early marrow progenitors and obtain multilineage effects. An improved understanding of the biologic and clinical effects of hematopoietic growth factors promises future clinical applications for conditions of impaired function and reduced numbers of blood cells.

Polypeptides controlling hematopoietic blood cell development and activation. II. Clinical results

Colony-stimulating factors (CSFs) have entered the clinical arena. Several investigators have explored, in first clinical phase I studies, different routes of administration to define the optimum biological dose, maximum tolerated dose, toxicity, and pharmacokinetics of these reagents. It has been demonstrated that recombinant human (rh) granulocyte-macrophage CSF (GM-CSF) and granulocyte CSF (G-CSF) can be safely administered over a broad dose range to increase number of circulating granulocytes in man. More recently, GM-CSF and G-CSF have been involved in phase Ib/II studies to assess the granulopoietic responses of patients with granulocytopenia due to various underlying disease states including myelodysplastic syndrome, aplastic anemia, cyclic neutropenia, Kostmann's syndrome, and the acquired immuno-deficiency syndrome. Both factors were also investigated with respect to their potential to prevent chemotherapy induced granulocytopenia or to accelerate recovery from that condition. The short-term effects of rh GM-CSF after autologous bone marrow transplantation for various solid tumors and lymphoid malignancies were assessed as well. In this article we will focus on recent results that have emerged from in vivo studies utilizing CSFs.

Quantitative enzyme immunoassay for human granulocyte colony stimulating factor (G-CSF)

Human granulocyte colony stimulating factor (G-CSF) was detected at the pM level by a simple sequential sandwich enzyme immunoassay. The polyclonal antiserum obtained by immunizing rabbits with recombinant G-CSF did not recognize other colony stimulating factors. The EIA developed gave satisfactory reproducibility as judged by an intra-assay precision of 4.3-6.2% and an interassay precision of 6.2-9.0%. Results from this assay procedure correlated well with those of a bioassay. The method could be performed within 6 h.

Production of macrophage-, granulocyte-, granulocyte-macrophage- and multi-colony-stimulating factor by peripheral blood cells

The specific cell sources and signals for induction of various colony-stimulating factors (CSF) in peripheral blood mononuclear cells (PBMC), purified T lymphocyte and monocyte (Mo) populations have been investigated. In the absence of exogenous activating stimuli, human PBMC, T cells and Mo failed to produce stable cytoplasmic mRNA for CSF for macrophages (M-CSF or CSF-1), for granulocytes (G-CSF), for granulocytes and macrophages (GM-CSF) and for multilineage CSF [multi-CSF, interleukin (IL) 3] and thus failed to release CSF proteins. However, after stimulation with phorbol myristate acetate and phytohemagglutinin, M-, G-, GM- and multi-CSF mRNA became detectable in PBMC, resulting in the secretion of the respective proteins. Identical culture conditions resulted in synthesis of only G- and M-CSF by purified Mo, whereas purified T lymphocytes produced GM-CSF and multi-CSF only. When Mo or T lymphocytes were exposed to recombinant human interferon-gamma or were stimulated by triggering the epitopes recognized by the monoclonal antibodies anti-Tll2 and Tll3, respectively, again disparate CSF expression patterns were found to be associated with both cell species. Moreover, IL2-receptive T lymphocytes showed the same distinct pattern of CSF secretion when activated by recombinant human IL2.

Polypeptides controlling hematopoietic cell development and activation. I. In vitro results

Recombinant DNA technology has been central in answering some of the most relevant questions in the research of regulation of the functional status of hematopoietic progenitor cells and their progeny. This leading article will focus on recent results that have emerged from studies utilizing recombinant molecules that control hematopoietic blood cell development and activation. The following features will be detailed: The molecular and biological characteristics and biochemistry of hematopoietic growth factors, synergizing factors and releasing factors, their role in the regulation of hematopoiesis and activation of normal and leukemic cells, their cellular sources, and regulation of production.

Structure and regulation of the erythroid system at the level of progenitor cells

Considerable ground has been covered since the first clonal assays for hemopoietic cells were described. The possibility of studying populations of progenitor cells and the regulatory factors that influence them has already thrown considerable light on our understanding of the structure and physiology of the normal erythroid system and its alterations in disease. The relative importance of humoral and short-range factors and of possible cell-to-cell interactions in the regulation of proliferation and differentiation in the erythroid cell lineage is now being studied actively in several laboratories. The possibility of analyzing possible regulatory networks involving such highly reactive cells as lymphocytes and monocytes-macrophages in defined in vitro conditions now exists. As these studies are being extended to the diseased state, concepts related to alterations in regulatory mechanisms in syndromes with abnormal cell proliferation can be tested. Clinical applications in the treatment of patients with hematological disease are being contemplated. The usefulness of Epo for the treatment of the anemia of renal disease has been demonstrated already.

Human hemopoietic growth factors

Hematopoiesis is regulated by a complex network of soluble stimulators and inhibitors, as well as by cellular interactions in the bone marrow microenvironment. Progress in molecular biology and protein biochemistry has provided a number of hemopoietic growth factors that are now available in large quantities for in vitro and in vivo studies. Several of them seem to hold great promise for patients suffering from insufficient hematopoiesis of various causes. This review focuses on new developments in the understanding of hemopoietic growth factors activity, and on recent clinical data.

Phase I study of granulocyte colony-stimulating factor in patients with transitional cell carcinoma of the urothelium

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was administered at a dose of 1-60 micrograms/kg of body weight to 22 patients with transitional cell carcinoma before chemotherapy as part of a Phase I/II study. In all patients, a specific dose-dependent increase in the absolute neutrophil count (ANC) of 1.8-12 fold was seen. In addition, this augmentation in the ANC was accompanied by an increase in leukocyte alkaline phosphatase, a marker of secondary granule formation. In six of eight patients analyzed, an increase in bone marrow myeloid to erythroid cell ratio was seen. Day 14 peripheral blood cell derived colony forming unit granulocyte macrophage were also increased by day 6 of rhG-CSF treatment. Circulating levels of eosinophils and basophils were unchanged; however, a 10-fold increase in monocytes was observed in patients treated at the highest doses. There was also a small increase in CD3+ lymphocytes that was not dose dependent. Hemoglobin, hematocrit, and platelet count remained near baseline throughout the period of rhG-CSF administration. These findings demonstrate that rhG-CSF is a potent stimulus for normal neutrophil proliferation and maturation.

Characterization of a human hematopoietic progenitor cell capable of forming blast cell containing colonies in vitro

A hematopoietic cell (CFU-B1) capable of producing blast cell containing colonies in vitro was detected using a semisolid culture system. The CFU-B1 has the capacity for self-renewal and commitment to a number of hematopoietic lineages. Monoclonal antibody to the human progenitor cell antigen-1 (HPCA-1) and a monoclonal antibody against the major histocompatibility class II antigen (HLA-DR) were used with fluorescence activated cell sorting to phenotype the CFU-B1. The CFU-B1 was found to express My10 but not HLA-DR antigen; experiments using complement-dependent cytotoxicity to eliminate DR positive cells confirmed this finding. Pretreatment of marrow cells with two chemotherapeutic agents, 5-fluorouracil and 4-hydroperoxycyclophosphamide facilitated detection of CFU-B1 derived colonies, while diminishing or totally inhibiting colony formation by other hematopoietic progenitor cells. CFU-B1-derived colony formation was dependent upon the addition of exogenous hematopoietic growth factors. Media conditioned either by the human bladder carcinoma cell line 5637 or lectin stimulated leukocytes, as well as recombinant granulocyte-macrophage colony stimulating factor, interleukin 3 or interleukin 1 alpha promoted blast cell colony formation. By contrast, neither recombinant erythropoietin, recombinant interleukin 4, purified macrophage colony stimulating factor or recombinant granulocyte colony-stimulating factor alone promoted blast cell colony formation.

Early events in human T cell ontogeny. Phenotypic characterization and immunohistologic localization of T cell precursors in early human fetal tissues

During early fetal development, T cell precursors home from fetal yolk sac and liver to the epithelial thymic rudiment. From cells that initially colonize the thymus arise mature T cells that populate T cell zones of the peripheral lymphoid system. Whereas colonization of the thymus occurs late in the final third of gestation in the mouse, in birds and humans the thymus is colonized by hematopoietic stem cell precursors during the first third of gestation. Using a large series of early human fetal tissues and a panel of monoclonal antibodies that includes markers of early T cells (CD7, CD45), we have studied the immunohistologic location and differentiation capacity of CD45+, CD7+ cells in human fetal tissues. We found that before T cell precursor colonization of the thymus (7-8 wk of gestation), CD7+ cells were present in yolk sac, neck, upper thorax, and fetal liver, and were concentrated in mesenchyme throughout the upper thorax and neck areas. By 9.5 wk of gestation, CD7+ cells were no longer present in upper thorax mesenchyme but rather were localized in the lymphoid thymus and scattered throughout fetal liver. CD7+, CD2-, CD3-, CD8-, CD4-, WT31- cells in thorax and fetal liver, when stimulated for 10-15 d with T cell-conditioned media and rIL-2, expressed CD2, CD3, CD4, CD8, and WT31 markers of the T cell lineage. Moreover, CD7+ cells isolated from fetal liver contained all cells in this tissue capable of forming CFU-T colonies in vitro. These data demonstrate that T cell precursors in early human fetal tissues can be identified using a mAb against the CD7 antigen. Moreover, the localization of CD7+ T cell precursors to fetal upper thorax and neck areas at 7-8.5 wk of fetal gestation provides strong evidence for a developmentally regulated period in man in which T cell precursors migrate to the epithelial thymic rudiment.

In vitro interferon-gamma production by cultured T-cells in severe aplastic anaemia: correlation with granulomonopoietic inhibition in patients who respond to anti-thymocyte globulin

T-cell-mediated inhibition of granulomonopoietic progenitors (CFU-GM) was studied in vitro in 27 patients with severe aplastic anaemia (AA). In nine out of 13 responders to anti-thymocyte globulin (ATG), cultured T-cells obtained prior to therapy, as well as their conditioned medium strongly suppressed both normal allogeneic and autologous CFU-GM (the latter obtained after marrow recovery). Addition of anti-interferon-gamma to the cultures abolished the suppressive effect on CFU-GM. After ATG therapy, no similar inhibitory effect was detected. Employing the panning method with monoclonal antibodies (CD4+ for inducer/helper and CD8+ for cytotoxic/suppressor T-cells) we were able to show that the cells responsible for in vitro CFU-GM inhibition were included in the cytotoxic/suppressor T-cell subpopulation. Cultured T-cells and their conditioned medium obtained from 14 non-responders to ATG did not show CFU-GM suppression. The mean interferon (IFN) levels in the T-cell conditioned media of ATG-responders was 625 +/- 125 mu/ml while in non-responders the level was 45 +/- 15 mu/ml (normal control levels 43 +/- 24 mu/ml). Freshly isolated peripheral blood lymphocytes from either group did not show any in vitro inhibitory effect. The response rate to ATG was statistically significant when the generation in culture of high versus low IFN production was compared (P = 0.0001). Experiments with T-cells obtained from heavily transfused thalassaemia major, and myelodysplastic syndrome patients, as well as normal volunteers, also did not demonstrate any suppression of CFU-GM. Our results indicate that the response rate to ATG is significantly higher in patients with AA who have an abnormal regulation of interferon-gamma (g-IFN) production.

Production of granulocyte colony-stimulating factor (G-CSF) by human cells: T lymphocyte-dependent and T lymphocyte-independent release of G-CSF by blood monocytes

To evaluate the production of granulocyte colony-stimulating factor (G-CSF) by human immune and inflammatory cells, an assay specifically measuring G-CSF activity in the presence of other cytokines was developed which was based on the proliferation of 32Dcl cells induced by G-CSF. Successful use of the 32Dcl cells to specifically measure G-CSF activity required the selection of cells highly responsive to G-CSF and with reduced responsiveness to interleukin 2 (IL 2) by intermittent culture in medium containing G-CSF. Furthermore, the addition of exogenous IL 2 to standards and experimental samples was necessary to ensure that the concentration of IL 2 was similar in all samples, since IL 2 directly stimulated the proliferation of 32Dcl cells and increased their responsiveness to G-CSF. A variety of stimuli were found to induce G-CSF release by blood monocytes. Lipopolysaccharide and monocyte adherence appeared to directly stimulate G-CSF release, whereas stimulation of G-CSF release from monocytes by mitogenic lectins required the presence of T lymphocytes. In all cases, release of G-CSF was detectable as soon as 4 h after stimulation and was essentially complete after 48 h. These findings indicate that G-CSF release can be initiated by a variety of pathways, and therefore suggest that the production of this mediator may occur in the course of many immune and inflammatory reactions.

Effect of granulocyte colony-stimulating factor on neutropenia and associated morbidity due to chemotherapy for transitional-cell carcinoma of the urothelium

We evaluated the ability of human recombinant granulocyte colony-stimulating factor (rhG-CSF) to prevent chemotherapy-induced neutropenia or to accelerate recovery from this complication and thus allow patients to receive full doses of antineoplastic agents on time, according to protocol design. Twenty-seven patients with transitional-cell carcinoma of the urothelium who were undergoing treatment with methotrexate, doxorubicin, vinblastine, and cisplatin were given rhG-CSF (up to 60 micrograms per kilogram of body weight per day) before their first cycle of combination chemotherapy, during the first cycle, or at both points. Treatment with rhG-CSF before chemotherapy resulted in a dose-dependent increase in the absolute neutrophil count. Treatment with rhG-CSF after chemotherapy significantly reduced the number of days (91 percent) per patient on which the absolute neutrophil count was 1000 per microliter or less (P = 0.0039), reduced the number of days (1 vs. 35) on which antibiotics were used to treat fever and neutropenia, and significantly increased the percentage (100 vs. 29 percent) of patients qualified to receive planned chemotherapy on day 14 of the treatment cycle (P = 0.0015). In addition, the incidence of mucositis was significantly decreased (11 vs. 44 percent, P = 0.041), as was its severity. These findings demonstrate that rhG-CSF is a potent stimulus of normal neutrophil proliferation and maturation. In addition, its administration can reduce both the hematopoietic and oral toxicity of chemotherapy.

Detection of a human hematopoietic progenitor cell capable of forming blast cell containing colonies in vitro

A progenitor cell CFU-B1 (blast cell colony forming unit) present in human bone marrow and capable of producing blast cell containing colonies in vitro was detected using a serum containing semisolid culture system. The CFU-B1 has the capacity not only to undergo self-renewal, but also commitment to a number of hematopoietic lineages. This progenitor cell therefore has characteristics which suggest that it is identical to or closely related to the human pluripotent hematopoietic stem cell. Pretreatment of marrow cells with 5 fluorouracil facilitated detection of CFU-B1 derived colonies. The formation of CFU-B1 derived colonies was dependent upon the addition of media conditioned by the human bladder carcinoma cell line 5637. The ability of 5637 CM (conditioned media) to support blast cell colony formation was in part but not totally ablated by pretreatment of the CM with an IL-1 alpha (interleukin-1) neutralizing antibody. This data suggests that IL-1 alpha plays a role in the regulation of primitive events occurring during human hematopoiesis. IL-1 alpha might be exerting these effects by either acting directly on the CFU-B1, causing marrow accessory cells to elaborate other cytokines or by synergizing with cytokines already present in 5637 CM.

The production of myeloid blood cells and their regulation during health and disease

The regulation of myelopoiesis in vivo most likely entails a complex set of interactions between cell-derived biomolecules and their target cells: hematopoietic stem and progenitor cells and accessory cells. Stimulating and suppressing factors have been characterized through in vitro studies, and their mechanisms of action in vitro and in vivo have begun to be elucidated. Among those factors being studied are the hematopoietic colony-stimulating factors (CSF): interleukin-3 (multi-CSF), granulocyte-macrophage-CSF, granulocyte-CSF, and macrophage-CSF; other molecules include erythropoietin, B-cell-stimulating factor-1, interleukin-1, interleukin-2, prostaglandin E, leukotrienes, acidic ferritins, lactoferrin, transferrin, the interferons-gamma, -alpha, and -beta, and the tumor necrosis factors-alpha and -beta (lymphotoxin). These factors interact to modulate blood cell production in vitro and in vivo. The proposed review characterizes these biomolecules biochemically and functionally, including receptor-ligand interactions and the secondary messengers within the cell which mediate their functional activity. The production and action of the molecules are described under conditions of hematopoietic disorders, as well as under normal conditions. Studies in vitro are correlated with studies in vivo using animal models to give an overall view of what is known about these molecules and their relevance physiologically and pathologically.

A comparison of methods for analysis of mRNA in hematopoietic cells: conventional and clonal northern analysis and in situ hybridization

Three methods for the detection of mRNA in hematopoietic cells are addressed, and examples using these techniques to examine human leukemic cells' genetic response to chemical and biological response modifiers shown. The limitations and specific applications of the three techniques are discussed.

Neutrophil activation on biological surfaces. Massive secretion of hydrogen peroxide in response to products of macrophages and lymphocytes

Recombinant tumor necrosis factor alpha (rTNF alpha) and beta (rTNF beta) did not trigger H2O2 release from PMN in suspension. However, when PMN were plated on polystyrene surfaces coated with serum, fibronectin, vitronectin, laminin, or human umbilical vein endothelial cells (HUVEC), rTNFs induced a massive, prolonged secretory response, similar to that elicited by phorbol myristate acetate (PMA) or bacteria. On serum-coated plates, the maximum sustained rate of H2O2 release in response to rTNF alpha was 2.6 +/- 0.2 nmol/min per 10(6) PMN, the same as that with PMA; release continued for 73 +/- 4 min. On laminin-coated surfaces or HUVEC, release of H2O2 in response to rTNFs was slower, but lasted approximately 3.5 h, reaching the same total (greater than 100 nmol/10(6) PMN). Not only was this response far longer and larger than for other soluble stimuli of the respiratory burst studied with PMN in suspension, but the concentration necessary to elicit a half-maximal response (EC50) for rTNF alpha was orders of magnitude lower (55 pM). Responses were similar with FMLP, but ranged from zero to small with recombinant IFN alpha, recombinant IFN beta, recombinant IFN gamma, platelet-derived growth factor, recombinant IL-1 beta, or bacterial lipopolysaccharide. Adherent monocytes did not secrete H2O2 in response to rTNFs. H2O2 secretion by adherent PMN was first detectable 15-90 min after addition of rTNFs or FMLP. This lag period was unaffected by prior exposure of PMN to rTNF alpha in suspension, by allowing PMN to adhere before adding rTNF alpha, or by incubating adherent PMN in medium conditioned by rTNF alpha-treated PMN. Cytochalasins abolished H2O2 secretion in response to rTNFs, but not FMLP, if added during, but not after, the lag period. Thus, H2O2 secretion from rTNF alpha-treated PMN appears to be a direct but delayed response that requires assembly of microfilaments during exposure to the cytokine. These results suggest that PMN adherent to intra- or extravascular surfaces may undergo a massive, prolonged respiratory burst at the command of macrophages and lymphocytes reacting to microbial products and antigens.

Synergy of interleukin 1 and granulocyte colony-stimulating factor: in vivo stimulation of stem-cell recovery and hematopoietic regeneration following 5-fluorouracil treatment of mice

The human bladder carcinoma cell line 5637 produces hematopoietic growth factors [granulocyte and granulocyte/macrophage colony-stimulating factors (G-CSF and GM-CSF)] and hemopoietin 1, which synergizes with CSFs to stimulate colony formation by primitive hematopoietic stem cells in 5-fluorouracil-treated mouse bone marrow. Molecular and functional properties of hemopoietin 1 identified it as identical to interleukin 1 alpha (IL-1 alpha). When bone marrow cells from 5-fluorouracil-treated mice were cultured in suspension for 7 days with recombinant human IL-1 alpha and/or G-CSF, it was found that the two factors synergized to enhance recovery of myelopoietic cells and colony-forming cells of both high and low proliferative potential. G-CSF alone did not sustain these populations, but the combination had greater-than-additive stimulating capacity. In vivo, 5-fluorouracil (150 mg/kg) produced profound myelosuppression and delayed neutrophil regeneration for up to 2 weeks in C3H/HeJ mice. Daily administration of recombinant human G-CSF or recombinant human IL-1 alpha accelerated recovery of stem cells, progenitor cells, and blood neutrophils by up to 4 days in 5-fluorouracil-treated C3H/HeJ and B6D2F1 mice. The combination of IL-1 alpha and G-CSF acted synergistically, reducing neutropenia and accelerating recovery of normal neutrophil numbers by up to 7 days. This was accompanied by accelerated regeneration of spleen colony-forming units and erythroid, myeloid, and megakaryocytic progenitor cells in marrow and spleen, with enhanced erythroid and granulocytic differentiation. These results indicate the possible therapeutic potential of combination therapy with IL-1 and hematopoietic growth factors such as G-CSF in the treatment of chemotherapy- or radiation-induced myelosuppression.

Production of hemopoietic growth factors and gamma-interferon by large granular lymphocytes from patients with T gamma lymphocytosis

Two patients with T gamma lymphocytosis in whom expanded large granular lymphocyte (LGL) populations were detected in peripheral blood and bone marrow are described. The surface antigen phenotypes of the LGL from these patients were similar with a major portion of cells carrying T3, T8, T11 and Leu7 markers. However, whereas fresh LGL from both patients demonstrated antibody-dependent cell cytotoxicity (ADCC), natural killer (NK) cell function was present in one case but absent in the other. Supernatants from enriched suspensions of the LGL unstimulated by exogenous antigen or mitogens were shown to contain significant amounts of hemopoietic growth factors colony-stimulating activity (CSA) and burst-promoting activity (BPA). In one case gamma-interferon was also detected. This study contributes to the accumulating evidence that LGL are able to generate factors which have the capacity to influence the proliferation of hemopoietic progenitor cells in vitro.

The human hematopoietic colony-stimulating factors

The complementary DNAs and genes encoding the four major human myeloid growth factors--granulocyte colony-stimulating factor, macrophage colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and interleukin-3--have all been molecularly cloned. These DNA clones have proved valuable for studying the molecular biology of these important regulatory molecules as well as for the large-scale production of the recombinant growth factor proteins. These advances have led to a much better understanding of the role of the myeloid growth factors in regulating hematopoiesis in vivo that should soon find practical application in clinical medicine.

Recombinant human granulocyte colony-stimulating factor. Effects on hematopoiesis in normal and cyclophosphamide-treated primates

We examined the in vivo effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in primates (cynomolgus monkeys) treated with subcutaneous doses of rhG-CSF for 14-28 d. A dose-dependent increase in the peripheral white blood cells (WBC) was seen, reaching a plateau after 1 wk of rhG-CSF treatment. The elevation of WBC was due to an increase in the absolute neutrophil count. These results demonstrate that rhG-CSF is a potent granulopoietic growth and differentiation factor in vivo. In cyclophosphamide (CY)-induced myelosuppression, rhG-CSF was able to shorten the time period of WBC recovery in two treated monkeys to 1 wk, as compared to more than 4 wk for the control monkey. Its ability to significantly shorten the period of chemotherapy-induced bone marrow hypoplasia may allow clinicians to increase the frequency or dosage of chemotherapeutic agents. In addition, the increase in absolute numbers of functionally active neutrophils may have a profound effect in the rate and severity of neutropenia-related sepsis. Furthermore, the activities reported here indicate a potential role for rhG-CSF in the treatment of patients with myelodysplastic syndrome, congenital agranulocytosis, radiation-induced myelosuppression, and bone marrow transplantation.

Purified colony stimulating factors (G-CSF and GM-CSF) induce differentiation in human HL60 leukemic cells with suppression of clonogenicity

Purified recombinant human granulocyte-macrophage colony-stimulating factor (rHGM-CSF) and purified native murine granulocyte-CSF (G-CSF) both induced differentiation in HL60 cells as evidenced by expression of granulocyte and macrophage membrane antigens, although this was not accompanied by morphological evidence of differentiation. Both types of CSF suppressed clonogenic HL60 cells with evidence of complete clonal extinction. The suppression of clonogenic HL60 cells was preceded in some experiments by CSF-stimulated proliferation of HL60 cells, and this was most evident in cultures containing low concentrations of fetal calf serum (FCS).

Biomolecule-cell interactions and the regulation of myelopoiesis

The regulation of myelopoiesis in vivo most likely entails a complex set of interactions between cell-derived biomolecules and their target cells. Much of what we currently know of these interactions has been derived from studies in vitro utilizing techniques for the purification of both the biomolecules and the cells producing and responding to these factors. Stimulating and suppressing influences have been uncovered, and with the cloning and purification of biologically active factors, studies assessing the actions of these molecules in vivo have begun. From studies in vitro it is apparent that many of the purified molecules can have move than one action and that different molecules can collaborate in a synergistic manner to enhance or suppress functional endpoints.

Human pluripotent hemopoietic colony stimulating factor: activities on human and murine cells

Human pluripotent colony stimulating factor (Pluripoietin) was shown to act synergistically with human pluripotent alpha-like colony-stimulating activity (Pluripoietin-alpha) supporting the proliferation and differentiation of human CFU-GM progenitor cells in vitro, increasing colony size and numbers. In addition, Pluripoietin enhanced cytotoxic activity of mature human neutrophil granulocytes in an antibody-dependent cellular cytotoxicity assay. Biological activities of Pluripoietin known so far suggest great potentials for clinical use. Preclinical in vivo studies of Pluripoietin in different disease situations may be feasible in mice, because Pluripoietin is active on granulocyte precursors and on a variety of other murine cells.

Recombinant human granulocyte colony-stimulating factor: effects on normal and leukemic myeloid cells

Experiments were conducted to isolate and characterize the gene and gene product of a human hematopoietic colony-stimulating factor with pluripotent biological activities. This factor has the ability to induce differentiation of a murine myelomonocytic leukemia cell line WEHI-3B(D+) and cells from patients with newly diagnosed acute nonlymphocytic leukemia (ANLL). A complementary DNA copy of the gene encoding a pluripotent human granulocyte colony-stimulating factor (hG-CSF) was cloned and expressed in Escherichia coli. The recombinant form of hG-CSF is capable of supporting neutrophil proliferation in a CFU-GM assay. In addition, recombinant hG-CSF can support early erythroid colonies and mixed colony formation. Competitive binding studies done with 125I-labeled hG-CSF and cell samples from two patients with newly diagnosed human leukemias as well as WEHI-3B(D+) cells showed that one of the human leukemias (ANLL, classified as M4) and the WEHI-3B(D+) cells have receptors for hG-CSF. Furthermore, the murine WEHI-3B(D+) cells and human leukemic cells classified as M2, M3, and M4 were induced by recombinant hG-CSF to undergo terminal differentiation to macrophages and granulocytes. The secreted form of the protein produced by the bladder carcinoma cell line 5637 was found to be O-glycosylated and to have a molecular weight of 19,600.