Release Of Colony-stimulating Factor Research Articles

Transferrin modulation of colony stimulating factor elaboration by adherent blood and bone marrow cells.

When added to cultured normal, adherent blood and marrow cells at concentrations of 25-100 micrograms/ml (3 X 10(-7) to 1.3 X 10(-6) M), human transferrin enhanced colony-stimulating factor (CSF) elaboration. Fe saturated and relatively unsaturated Tf were equally effective in increasing CSF release, but soluble ferric nitriloacetate was ineffective. Dose-dependent increases in CSF release by adherent blood and marrow cells occurred in serum-free media and the continuous presence of Tf was necessary for this effect. Using a monoclonal anti-Tf receptor antibody, normal blood mononuclear cells contained no detectable Tf receptor positive cells. However, after 5 d culture in serum-free medium, Tf receptor positive cells were identified among normal adherent blood cells, and the per cent receptor positive cells increased with Tf concentration. We conclude Tf modulates CSF production from normal, adherent blood and marrow cells in vitro. These findings indicate a possible role for Tf in intramedullary regulation of normal granulopoiesis.

Characterization of biological response modifier release by human monocytes cultured in suspension in serum-free medium

Human monocytes have been shown to be critical immunoregulatory cells for a variety of frequently measured in vitro human immune functions and are secretors of potent biologic response modifiers (BRMs). These BRMs, such as interferon (IFN), colony stimulating factor (CSF) and prostaglandin E (PGE), may play important roles in the host immune response to cancer. A new approach for culturing circulating peripheral blood monocytes has been developed to retain the native characteristics of these cells, avoiding possible alteration or activation by adherence. The ability of elutriator-purified human monocytes to secrete IFN and PGE was examined under conditions of suspension culture as well as after adherence, and no difference in secretion of these BRMs was noted. In contrast, Teflon-cultured monocytes demonstrated a significantly enhanced CSF release over culturing in polystyrene plates. A new serum-free medium has also been developed, and monocytes cultured in vitro in this medium showed a 5-fold increase in IFN release, and up to a 72% increase in CSF release when compared to optimal standard culture medium (containing 10% AB serum) and an increased stimulation index for PGE release. By these procedures, hundreds of millions of highly purified human monocytes can be sterilely isolated in suspension and cultured in suspension in serum-free medium with retention of BRM-releasing capabilities. This system should permit more detailed molecular studies of monocytes (in which serum can be an impediment) and may also facilitate clinical therapy studies involving the in vivo transfer of monocytes activated in suspension in vitro.

Phagocytosing Neutrophils Rapidly Release a Factor Which Inhibits Granulopoiesis in vitro

Phagocytosis of the heat-killed opsonised yeast, Candida guilliermondii, by human neutrophils resulted in the rapid release of a potent factor which suppressed granulopoiesis in vitro. The factor has been shown to act on monocytes and macrophages by inhibiting the production and release of colony-stimulating factor (CSF) which is the specific stimulator of granulocytic colony-forming cell (CFUc) proliferation in vitro. When added directly to target cells containing CFUc, the inhibitory factor had no effect on colony growth. The absence of detectable inhibitor in media conditioned for short periods with resting neutrophils or neutrophils challenged with unopsonised Candida which are not phagocytosed confirmed that active phagocytosis was the stimulus for inhibitor release. In further experiments, addition of endotoxin to the cultures was shown to suppress the inhibitory effect. We suggest that feedback inhibition of CSF production in vivo may be mediated by products derived from phagocytosing neutrophils.

FAILURE OF CHRONIC-GRANULOCYTIC-LEUKAEMIA LEUCOCYTES TO RELEASE AN INHIBITOR OF GRANULOPOIESIS

Phagocytosing, but not resting, neutrophils normally release an inhibitor of in-vitro granulopoiesis which suppresses the production or release of colony-stimulating factor by monocytes and macrophages. Neutrophils from 12 patients with chronic granulocytic leukaemia (CGL) were found to contain the inhibitor, but in 11 of the 12 patients there was failure to release significant amounts during phagocytosis. It is suggested that such a defect in the feedback control of granulopoiesis could lead to the progressive inappropriate accumulation of morphologically normal granulocytes, as seen in CGL.

Production of a colony-stimulating factor following differentiation of leukemic myleoblasts to macrophages.

Leukemic cells in the myeloblastic stage from a murine myeloid leukemia cell line (M1) were induced to differentiate to macrophages by lipopolysaccharide (LPS) from Gram-negative bacteria. A granulocyte-macrophage colony-stimulating factor (CSF) was produced only during differentiation. After induction of differentiation, the continued presence of LPS was necessary to stimulate the macrophages to release CSF. In contrast, a macrophage cell line (Mm-1) derived from the M1 line produced CSF without LPS-stimulation, but CSF release was stimulated by the presence of LPS.

Lack of Relationship Between Toxicity and Bone Marrow Cell Colony Stimulating Activity of Endotoxin Preparations

SummaryThe release of colony stimulating factor (CSF) by endotoxin was studied using several endotoxin preparations differing greatly in their toxicities measured as mouse LD50. No correlation was found between lethality and CSF release. It is concluded that the toxic effect of endotoxin is not required for the generation of CSF.Furthermore, the component in the polysaccharide rich and lipid free, nonendotoxic, partially hydrolyzed endotoxin breakdown product (called PS), which can stimulate the CSF release in mice, is sensitive to periodate oxydation.

Effect of Levamisole on Human Granulopoiesis in Vitro

SummaryThe effect of levamisole, a potent immunomodulator, was studied on granulopoiesis in vitro. Low concentrations of levamisole stimulated monocytes and macrophages and resulted in enhanced colony stimulating factor (CSF) release. Higher concentrations of levamisole were inhibitory to CSF release. Levamisole did not affect bone marrow directly to produce stimulation or inhibition of granulopoiesis. Levamisole did not degrade or potentiate preformed CSF. Improved survival of infected animals may in part be related to increased granulopoiesis. The dose-related effect of levamisole on CSF release by the monocyte-macrophage system may be responsible for the variable effect on the neu-trophil system noted in vivo.The authors gratefully acknowledge the expert technical assistance of Ms. Carla Drebing.

Regulation of Lipopolysaccharide-Induced Granulopoiesis and Macrophage Formation by Spleen Cells

Abstract Addition of bacterial lipopolysaccharide (LPS), a B cell mitogen, to mouse spleen cultures strongly stimulated production of colony-stimulating factor (CSF), the humoral regulator of granulopoiesis, and macrophage formation in vitro. Secretion of CSF from LPS-stimulated spleen cells coincided with cellular DNA synthesis and cell transformation and both activities could be attributed to the lipid A moiety of the molecule. Different experimental approaches were used to study the relationship of CSF release and lymphocyte activation in response to LPS: a) modification of LPS with polymyxin B, an antibiotic bactericidal for most Gram-negative bacteria, caused a marked reduction in mitogenic activity, although the ability to induce CSF was not significantly altered; b) spleen cells from CBA/N mice, a mutant strain with an x-linked genetic defect in immunologic and mitogenic responses to polyclonal activators including LPS, showed diminished mitogenic responses; however, high levels of CSF were produced; c) mitotic and DNA inhibitors (colchicine and cytosine arabinoside) did not affect CSF release although they completely inhibited mitogenicity. Thus, the spleen cell population participating in the process of LPS-induced CSF generation is probably a nondividing, terminally differentiated one without need for DNA synthesis. In addition, it was also shown that active RNA and protein synthesis are needed in this process.

The effect of cyclic AMP on human colony forming cell and colony stimulating factor production

The effect of cyclic AMP (cAMP) and related nucleotides on human colony forming cells (CFC) and those cells producing colony stimulating factor (CSF) was studied in vitro. When added at physiological concentrations (10(-2) to 1 micron), exogenous cAMP stimulated maximum colony formation in cultures without feeder layers. Related nucleotides stimulated colony formation to a lesser extent and in decreasing order of free energy. All nucleotides inhibited colony formation in concentrations above 1 micron. A velocity sedimentation cell separation technique was used to obtain cell fractions rich in CFC but poor in CSF-producing cells. Such fractions did not respond to cAMP stimulation. These studies suggest that exogenous cAMP stimulates human bone marrow to form colonies in vitro by increasing the release and/or production of endogenous CSF.

Studies on the bone marrow colony stimulating factor (CSF): relation of tissue CSF to serum CSF.

AbstractFluctuations in the colony stimulating factor (CSF) content of submaxillary salivary gland, lung, kidney and spleen were studied in male C57BL mice which had been subjected to a variety of stimuli (endotoxin, x‐irradiation or polyadenylic‐polyuridylic acid complex) that caused elevations of the serum CSF. The temporal relationships and magnitudes of the rises in CSF were complex and differed from tissue to tissue according to the stimulus used. In the tissues examined not only was the measurable CSF content in each case found to equal or exceed the prestimulatory levels, but in some cases distinctly different forms of CSF were observed as shown by differences in the zone sedimentation, electrophoretic, and calcium phosphate binding characteristics of the material. The patterns of response to the stimuli investigated suggested that tissue injury either directly, or indirectly via the release of various cellular constituents, might mediate the release of CSF by various widely disseminated and/or differing cell types.