Neutrophil Colony Formation Research Articles

G-CSF suppresses allergic pulmonary inflammation, downmodulating cytokine, chemokine and eosinophil production

AimsGranulocyte Colony-Stimulating Factor (G-CSF), which mobilizes hemopoietic stem cells (HSC), is believed to protect HSC graft recipients from graft-versus-host disease by enhancing Th2 cytokine secretion. Accordingly, G-CSF should aggravate Th2-dependent allergic pulmonary inflammation and the associated eosinophilia. We evaluated the effects of G-CSF in a model of allergic pulmonary inflammation. Main methodsAllergic pulmonary inflammation was induced by repeated aerosol allergen challenge in ovalbumin-sensitized C57BL/6J mice. The effects of allergen challenge and of G-CSF pretreatment were evaluated by monitoring: a) eosinophilia and cytokine/chemokine content of bronchoalveolar lavage fluid, pulmonary interstitium, and blood; b) changes in airway resistance; and c) changes in bone-marrow eosinophil production. Key findingsContrary to expectations, G-CSF pretreatment neither induced nor enhanced allergic pulmonary inflammation. Instead, G-CSF: a) suppressed accumulation of infiltrating eosinophils in bronchoalveolar, peribronchial and perivascular spaces of challenged lungs; and b) prevented ovalbumin challenge-induced rises in airway resistance. G-CSF had multiple regulatory effects on cytokine and chemokine production: in bronchoalveolar lavage fluid, levels of IL-1 and IL-12 (p40), eotaxin and MIP-1a were decreased; in plasma, KC, a neutrophil chemoattractant, was increased, while IL-5 was decreased and eotaxin was unaffected. In bone-marrow, G-CSF: a) prevented the increase in bone-marrow eosinophil production induced by ovalbumin challenge of sensitized mice; and b) selectively stimulated neutrophil colony formation. SignificanceThese observations challenge the view that G-CSF deviates cytokine production towards a Th2 profile in vivo, and suggest that this neutrophil-selective hemopoietin affects eosinophilic inflammation by a combination of effects on lung cytokine production and bone-marrow hemopoiesis.

Recombinant human granulocyte colony-stimulating factor after kidney transplantation: a retrospective analysis to evaluate the benefit or risk of immunostimulation.

Leukopenia due to immunosuppressive drugs represents a well-known complication in graft recipients, which might put patients at an increased risk for infections. In this study, recombinant human granulocyte colony-stimulating factor (rhG-CSF), a hematopoietic growth factor that selectively stimulates neutrophil colony formation and neutrophil cell differentiation, was tested for safety and efficacy. We evaluated 30 episodes of leukopenia (<2000/mm3) in 19 kidney graft recipients treated with rhG-CSF. This cohort was compared with an age- and sex-matched historical control group without therapy. Peripheral and differential blood cell counts were analyzed, and the duration of leukopenia was estimated. Furthermore, the occurrence of infections associated with leukopenia was investigated. All patients responded to rhG-CSF therapy. Peripheral leukocyte counts increased from 1756+/-582 to a peak of 8723+/-3038/mm3 (P<0.0001). On the average, the peak was reached after 2.7 days (range 1 to 8). Furthermore, the effect was fairly persistent, because in 22 of 30 episodes leukocyte counts were within the normal range after 7 days. The elevation of total leukocytes was mainly due to a specific increase in neutrophil granulocytes from 1143+/-514 to 6895+/-1950/mm3 on the peak day (P<0.0001). Patients in the G-CSF group were leukopenic for a mean of 1.29+/-0.59 days, whereas in the control group leukopenia persisted for at least 7 days. Consequently, the rate of infections was significantly higher (P<0.045) in nontreated patients. rhG-CSF was safe and effective in leukopenic kidney graft recipients. Leukopenic episodes in treated patients were significantly shorter, and infections occurred at a significantly lower rate. No evidence was found that rhG-CSF therapy might trigger rejection episodes, and no side effects were observed.

In Vitro Comparison of the Biological Potency of Glycosylated versus Nonglycosylated rG-CSF

The biological potency of 2 recombinant human granulocyte colony-stimulating factors (rG-CSF) formulated for clinical use (lenograstim and filgrastim) together with a nonmarketed Escherichia coli-derived rG-CSF were compared by duplicate neutrophil colony assays in 3 normal human marrows. Serial doubling dilutions of each rG-CSF (128 to 0.008 ng/ml) were used. Neutrophil colonies were blindly scored at day 14. Lenograstim stimulated neutrophil colony formation at doses 16 times lower than that of the 2 nonglycosylated rG-CSFs and was twice as potent as filgrastim at maximal colony stimulation. Qualitative differences in colony size were also noted. Both nonglycosylated rG-CSFs (filgrastim and research-use rG-CSF) gave inferior qualitative and quantitative results, suggesting that glycosylation gives lenograstim a potency advantage.

Cytokine-mediated protein kinase C activation is a signal for lineage determination in bipotential granulocyte macrophage colony-forming cells.

Granulocyte macrophage colony-forming cells (GM-CFC) have the potential to develop into either macrophages and/or neutrophils. With a highly enriched population of these cells we have found that although GM-CFC are equally responsive to macrophage colony stimulating factor (M-CSF) and stem cell factor (SCF) in terms of DNA synthesis, M-CSF stimulated the development of colonies containing macrophages in soft gel assays, while SCF promoted neutrophilic colony formation. When SCF and M-CSF were combined, mainly macrophage development was stimulated both in soft agar colony-forming assays and liquid cultures. An analysis of some potential signaling mechanisms associated with cytokine-mediated developmental decisions in GM-CFC revealed that M-CSF, but not SCF, was able to chronically stimulate phosphatidylcholine breakdown and diacylglycerol production, indicating that protein kinase C (PKC) may be involved in the action of M-CSF. Furthermore, M-CSF, but not SCF, can increase the levels of PKC alpha (PKC alpha) expression and stimulate the translocation of PKC alpha to the nucleus. When the PKC inhibitor, calphostin C, was added to GM-CFC cultured in M-CSF then predominantly neutrophils were produced, conversely PKC activators added with SCF stimulated macrophage development. The data indicate a role for PKC in M-CSF-stimulated macrophage development from GM-CFC.

Interleukin-4--a dual regulatory factor in hematopoiesis.

Interleukin-4/B-cell stimulatory factor-1 (IL-4/BSF-1) is a unique cytokine which may have multiple regulatory functions in vitro and in vivo. It has been shown to produce diverse effects on hematopoietic progenitors and can act on the proliferation and differentiation of committed as well as primitive hematopoietic progenitors. It acts synergistically with G-CSF to support neutrophil colony formation. In contrast, it inhibits IL-3-dependent colony formation and macrophage colony formation supported by IL-3 plus M-CSF, GM-CSF, or by M-CSF alone. It also suppresses pure and mixed megakaryocyte colony formation supported by IL-3 in the presence of Erythropoietin (EPO). IL-4, however, supports multipotential blast cell colony formation. And there are apparent differences between the functions of IL-4 and IL-3. IL-4 is able to exert its hematopoietic actions directly and indirectly. For example, it enhances the release of GM-CSF or G-CSF from T-lymphocytes and TNF-alpha from monocytes. Since IL-4 receptors have been shown to be expressed on bone marrow stromal cells as well as hematopoietic cells, it may also act in the bone marrow microenvironment. These results suggest that IL-4 is an intermediate-acting, lineage-non-specific factor just like IL-3 or GM-CSF. Complex interactions between many cytokines including IL-4 may act in the regulation of normal as well as pathological hematopoiesis.

Human serum stimulates the production of G-CSF, IL-1, IL-6 and IL-8 by human peripheral blood leucocytes.

Human serum induces human peripheral blood leucocytes (PBL) to release an activity stimulating neutrophil colony formation (G-CSA) from human bone marrow cells. By titrating individual growth factors and using specific neutralizing antibodies we showed that: human serum contains very low levels of G-CSF which are by themselves insufficient to stimulate myeloid colony formation in primary human bone marrow cultures and cannot account for the serum releaser activity; that although no detectable levels of IL-1, IL-2, IL-3, IL-4, IL-6 or IL-8 are found in the serum, anti IL-1 antibodies partially block the release of G-CSA when added early during PBL incubation; that PBL incubated in the absence of serum for 2 d produce small amounts of IL-1, IL-6, IL-8 and G-CSF and this is increased 6-16 fold in the presence of human serum; and that the neutrophil colony-stimulating activity released by PBL incubated with human serum is G-CSF.

The mechanism responsible for diminished neutrophil production in neonates delivered of women with pregnancy- induced hypertension

The neonatal neutropenia after pregnancy-induced hypertension is a function of diminished neutrophil production. These studies test the hypothesis that this diminution is due to decreased production of neutrophilic growth factors, reduced responsiveness of neutrophil progenitors to these factors, or the presence of an inhibitor. While the concentrations of placentally derived colony-stimulating factors were similar in normotensive and hypertensive gestations, bioassay demonstrated less colony-stimulating activity in placental conditioned media from hypertensive gestations. Evaluation of the responsiveness of progenitors to recombinant factors revealed no differences between those from normotensive and hypertensive gestations. However, neutrophilic colony formation in vitro was significantly inhibited after the addition of conditioned media or sera from hypertensive gestations, whereas the addition of these from normotensive gestations had no inhibitory effect. Thus this common maternal-fetal disorder is associated with an inhibitor of neutrophil production, which is elaborated by the placenta and present in cord blood serum.

Identification of a common signal associated with cellular proliferation stimulated by four haemopoietic growth factors in a highly enriched population of granulocyte/macrophage colony-forming cells.

We have prepared a population of bone marrow cells that is highly enriched in neutrophil/macrophage progenitor cells (GM-CFC). Four distinct haemopoietic growth factors can stimulate the formation of mature cells from this population, although the proportions of neutrophils and/or macrophages produced varied depending on the growth factor employed: interleukin 3 (IL-3) and granulocyte/macrophage colony-stimulating factor (GM-CSF) stimulated the formation of colonies containing both neutrophils and macrophages; macrophage colony-stimulating factor (M-CSF) produced predominantly macrophage colonies; and granulocyte colony-stimulating factor (G-CSF) promoted neutrophil colony formation. Combinations of these four growth factors did not lead to any additive or synergistic effect on the number of colonies produced in clonal soft agar assays, indicating the presence of a common set of cells responsive to all four haemopoietic growth factors. These enriched progenitor cells therefore represent an ideal population to study myeloid growth-factor-stimulated survival, proliferation and development. Using this population we have examined the molecular signalling mechanisms associated with progenitor cell proliferation. We have shown that modulation of cyclic AMP levels has no apparent role in GM-CFC proliferation, whereas phorbol esters and/or Ca2+ ionophore can stimulate DNA synthesis, indicating a possible role for protein kinase C activation and increased cytosolic Ca2+ levels in the proliferation of these cells. The lack of ability of all four myeloid growth factors to mobilize intracellular Ca2+ infers that these effects are not achieved via inositol lipid hydrolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Predominant suppression of neutrophil colony growth by recombinant human tumor necrosis factor.

To investigate the suppressive effect of recombinant human tumor necrosis factor (rH-TNF) on colony growth of human granulocyte-macrophage progenitor cells (CFU-GM), cytochemical examinations of CFU-GM colonies were performed by a triple staining method. Each colony was classified into five subtypes, and the effects of rH-TNF on each subtype were analyzed. Neutrophil colony growth was inhibited by rH-TNF in a dose-dependent manner, and it was almost completely suppressed at 100 U/ml. In contrast, no significant suppressive effect of rH-TNF was found on the growth of monocyte-macrophage and eosinophil colonies at 100 U/ml or less. When recombinant human granulocyte colony-stimulating factor which almost exclusively stimulates neutrophil colony formation was used as a source of colony-stimulating activity, the total colony growth was almost completely suppressed by 100 U/ml of rH-TNF. These results indicate predominant inhibition of neutrophil colony growth by rH-TNF.

Morphologic and functional heterogeneity of chronic neutropenia of childhood with normal neutrophil colony formation in vitro

In order to obtain further knowledge of chronic neutropenia of childhood, we studied nine neutropenic infants six to ten months of age by in vitro techniques, including bone marrow culture, electron microscopy, and chemotaxis assay. Eight of the nine patients had a benign clinical course and the bone marrow aspirates showed a reduced number of segmented neutrophils. The ninth patient had a moderately severe course and the bone marrow showed maturation arrest at the promyelocyte stage. Bone marrow cultures demonstrated that the in vitro neutrophil colony formation and production of colony-stimulating activity were normal in all of the eight patients studied. Neutrophils from one of the nine patients had ultrastructural abnormalities such as decrease in number of primary and secondary granules and the presence of myelin figures in primary granules. Neutrophil chemotaxis was defective in three of the nine patients. All of the six patients in whom the neutrophil colony formation in agar, the ultrastructure of neutrophils, and neutrophil chemotaxis were normal recovered from the neutropenia between 11 and 30 months of age. These in vitro parameters appear to be useful for evaluating chronic neutropenia of childhood.

Expression of DR antigens on early human progenitors of neutrophilic and eosinophilic colonies in diffusion chambers (CFUd).

Incubation of the non-adherent low density cells from normal human bone marrow with an antiserum to DR antigens markedly inhibited their capacity to form granulocytic colonies in fibrin clot diffusion chambers implanted intraperitoneally into irradiated mice. The inhibitory effect of antiserum was abrogated after absorption of antiserum with B cells. Inhibition was obtained both with and without complement treatment. Neutrophilic colony formation exhibited a higher sensitivity to diluted antiserum to DR antigens as compared with eosinophilic colony formation. These results suggest that DR determinants are expressed on the neutrophilic and eosinophilic progenitor cells (CFUd) which give rise to colonies in diffusion chambers.

Regulation of macrophage and granulocyte proliferation. Specificities of prostaglandin E and lactoferrin

Hemopoietic colony-forming cells committed to macrophage differentiation (M-CFC) are selectively and differentially inhibited by prostaglandin E (PGE). A hierarchy of sensitivity was observed among murine CFC stimulated by colony-stimulating factors (CSF) which differ in their ability to initiate proliferation of morphologically distinct colony types, or stimulated by CSF provided by macrophage feeder layers. Inhibition of macrophage colony formation to 50 percent levels occurred with PGE concentrations between 10(-8) and 10(-9) M, and was still evident at 10(-10) -10(-11) M PGE concentrations. The growth of mixed colonies containing both macrophages and neutrophils was less sensitive to the inhibitory effects of PGE, however, the monocytoid component of these colonies was reduced in the presence of PGE. Neutrophil progenitor cell proliferation was not influenced by PGE concentrations below 10(-6) M, regardless of time of addition of PGE, whereas clonal macrophage expansion, as well as clone size, was sensitive to inhibition by PGE when added as late as 3 d after culture initiation. Prostaglandin F(2alpha), was not inhibitory to colony formation. Experimental evidence for a selective role of macrophage PGE in the regulation of macrophage colony formation was directly provided by utilizing resident peritoneal macrophages as a source of CSF for bone marrow target cell overlays. Simultaneous morphological analysis of colonies proliferating in bilayer culture in response to increasing concentrations of macrophages, and direct measurements of PGE synthesized by an identical number of macrophages maintained in liquid culture demonstrate that a specific decline in macrophage colony formation occurs coincident with a linear increase in macrophage PGE synthesis. Inhibition of macrophage PGE synthesis by indomethacin results in the specific enhancement of macrophage colony formation. Furthermore, macrophage PGE synthesis is induced by CSF preparations with the selective capacity to differentially stimulate macrophage proliferation, but not by those which preferentially stimulate granulocyte colony formation. In comparison to the effects of PGE on M-CFC, polymorphonuclear granulocyte-derived lactoferrin (LF) reduces macrophage production of colony-stimulating activities for macrophage, mixed macrophage- neutrophil and neutrophil colony formation. The ability of LF to reduce macrophage PGE synthesis, presumably by decreasing CSF production, suggests that LF and PGE can interact in the control of macrophage and granulocyte proliferation.

The effect of syngeneic peripheral blood cells on the formation of colonies by normal human bone marrow cells in diffusion chambers in mice.

This paper describes the influence of cells capable of releasing colony stimulating activity (CSA) in vitro on the formation of granulocytic colonies by normal human bone marrow in diffusion chambers in mice. A carbonyl iron method was used to remove phagocytic cells from normal human bone marrow. This treatment prevented spontaneous colony and cluster formation when the cells were cultured in agar in vitro at initial concentrations of 2-5 x 105 cells per ml. However, non-phagocytic bone marrow cells formed granulocytic colonies when inoculated into diffusion chambers at 105 cells per chamber and cultured in 450 R-irradiated or non-irradiated mice. The formation of granulocytic colonies by carbonyl iron treated marrow in diffusion chamber cultures was not consistently enhanced by the admixture of 1.4 x 105 1500 R-irradiated syngeneic light density blood cells (less than 1.077 g/ml) to the chamber inoculum. In contrast, these cells induced cluster or colony formation when added in the same proportion to the marrow cells in agar cultures in vitro. Addition of 1.4 x 105 1500 R-irradiated high density blood cells(greater than 1.077 g/ml) to the inoculum resulted in a slight, non-significant decrease in the number of colonies in diffusion chambers. The stimulating effect of host irradiation on neutrophilic colony formation was independent of the presence of CSA releasing cells in the chamber inoculum.