Serum colony stimulating factor levels in irradiated germfree and conventional GFW mice

On radiation damage to normal tissues and its treatment. I. Growth factors

The first part of the review outlines the classical interpretation of radiation damage to normal organs based on dose-response relationships for clonogenic cell survival and tissue kinetics. Proliferative organization of critical cell lineages (three-compartmental or H-type and one-compartmental or F-type) is considered as an additional determinant in the development of overt radiation injury. This leads to testable predictions concerned with divergent outcomes of stimulation of cell proliferation after radiation exposure using polypeptide growth factors. The prediction of favourable effects of such stimulation in H-type lineages is borne out by recent experiments on treatment with cytokines of radiation-induced haemopoietic insufficiency. The second prediction of deleterious effects of proliferative stimulation in recently, heavily irradiated F-type cell lineages remains to be verified or refuted.

Suppression of in vitro haematopoiesis following human immunodeficiency virus infection

Viral infections are frequently associated with haematological disorders. Abnormalities including leukopenia, anaemia and thrombocytopenia are commonly observed in patients with the acquired immune deficiency syndrome (AIDS) or the AIDS-related complex (ARC). The underlying cause of these haematological abnormalities is poorly understood. We report here that bone marrow progenitors isolated from AIDS or ARC patients are responsive to recombinant human granulocyte-macrophage colony stimulating factor (rGM-CSF) and recombinant erythropoietin. Antibodies present in the serum of patients infected with the human immunodeficiency virus (HIV), however, could suppress the growth of these progenitors, but not the growth of progenitors from HIV seronegative controls. A component of this immune-mediated suppression appears to be antibodies directed towards the envelope glycoprotein (gp120) of HIV.

In vitro production of granulocyte-macrophage colony-stimulating activity by murine bone marrow and spleen following vinblastine administration in vivo

The production of granulocyte-macrophage colony-stimulating activity (CSA) by isolated murine femur shafts, non-dispersed bone marrow and spleens was assessed following administration of Vinblastine (VLB). These organs were removed from 2 h to 10 days post-VLB and allowed to condition endotoxin-free medium for 48 h. CSA activity was assessed using a soft agar cloning system. The data demonstrate that CSA elaboration was maximal 24 h post-VLB, corresponding to the nadir of bone marrow GM-CFC, and 6 h after splenic reached a minimum. No relationship between peripheral blood granulocyte count or serum endotoxin levels were observed.

Lithium-stimulated recovery of granulopoiesis after sublethal irradiation is not mediated via increased levels of colony stimulating factor (CSF)

We have previously demonstrated that lithium (Li) is an effective agent in accelerating the recovery of granulopoiesis following sublethal (2 Gy) whole body irradiation. In this report, studies are described that further define this Li-mediated recovery by measuring the levels of colony-stimulating factor (CSF) present in serum from mice administered 105 micrograms/mouse (total dose) of ultra-pure Li2CO3 for 3 days immediately following irradiation. On days 1-28 following the last lithium dose, the serum was tested for its CSF activity against both normal non-adherent derived bone marrow target cells and non-adherent marrow cells from mice administered cyclophosphamide (200 mg/kg body weight). Serum was assayed at 0.01, 0.1, 1 and 10 per cent final concentration. No significant difference in the total number of CFU-GM was observed from normal marrow using either serum from irradiated mice or lithium-treated and irradiated mice, although the irradiation did produce a 300 per cent rise in CFU-GM colonies compared to normal serum (days 4 and 10-15). From regenerating marrow, we observed a significant difference (P less than or equal to 0.01) in CFU-GM cultured with serum at 0.1 per cent concentration from irradiated and lithium-treated mice compared to irradiated mice without lithium. The presence of CSF was confirmed by its reduced activity in the presence of anti-(CSF). These results suggest (Li) may increase the sensitivity of CFU-GM to CSF, thereby producing more CFU-GM ultimately providing more circulating granulocytes.

[Humoral factors in the regulation of cell proliferation in haematopoiesis. I. Granulopoiesis and lymphopoiesis (author's transl)]

Humoral Factors obviously play an important role in the maintenance of the steady state in haematopoiesis. There has been work on stimulators and inhibitors for several years. Colony-stimulating factor is the best characterized chemically and biologically. Interest in more or less cell-line-specific stimulators and inhibitors of lymphopoiesis is now growing. Various tissue extracts and cell culture supernatants have been partially purified and characterized biologically and chemically. Monocytes, producing stimulators and inhibitors, have a central function in the regulation of cell proliferation in haematopoiesis. Experiments performed in vitro can help better to understand data so far difficult to explain regarding patients with disturbed haematopoiesis. The in vivo relevance of these experiments, however, remains unclear.

Buoyant density analysis of myeloid colony-forming cells in germfree and conventional mice

Granulocyte-macrophage colony-forming cells (CFUc), in the bone marrow of germfree and conventioal CBA mice, were compared quantitatively and qualitatively. Cells were separated on the basis of their buoyant density by equilibrium centrifugation in continuous albumin density gradients. CFUc in the density subpopulations were detected by culture in agar containing three different types of colony stimulating factor (CSF). The sources of the CSF were post-endotoxin mouse serum (CSFES), mouse lung conditioned medium (CSFMLCM) and human urine (CSFHU). Mice were removed from the germfree environment and the buoyant density status of their CFUc was examined 1, 4 and 8 weeks later. No difference was found between germfree and conventional mice in the number of nucleated cells per femur or in their modal density. Neither was the number of CFUc per femur different. The cell cycle status of CFUc, as determined by the thymidine suicide technique was not significantly different. Functional heterogeneity was found among the density subpopulations for both groups of mice. This depended on the type of CSF. The density distribution of CFUc was significantly different in germfree mice. There were proportionately more low density CFUc. The mean modal density of CFUc under CSFES stimulation was less by 0.0045 g/cm3 in germfree mice. The removal of mice from the germfree environment resulted in a shift of the distribution to higher densities. The trend was towards the conventional situation. The significance of the buoyant density status of CFUc is discussed.

Colony stimulating activity in acute and chronic endotoxinemia in man

Blood granulocyte-macrophage colony stimulating activity (GM CSF) was measured in 6 normal individuals challenged with low-dose endotoxin and in 63 unselected patients with nonhaematological disorders. 5/63 patients were febrile and 5 other patients whoed detectable endotoxin levels, as measured by the Limulus assay. CSA levels showed a rapid increase in normal individuals following endotoxin administration, but were in the normal range in patients with chronic endotoxinemia or in those with febrile disorders. Thus, unlike acute endotoxinemia, chronic endotoxinemia is not associated with elevated activity that promotes growth of myeloid commited stem cells. In addition, fever per se did not coincide with elevated blood CSA levels.

Endotoxin-induced colony stimulating activity in normal and myeloid leukaemic subjects

Low doses of endotoxin were administered to normal and acute anc chronic myeloid leukaemic subjects. Temperature, leucocyte count, blood colony stimulating activity and the number of circulating colony forming units were monitored. All subjects acquired fever while the leucocyte count remained unaltered. Blood CSA rose sharply in 6 normal individuals, but failed to increase in 4 acute leukaemic patients and in 2 patients with CML in blast crisis. 2 patients with CML in the chronic stage increased their blood CSA comparable to normal individuals. The number of circulating colony forming units rose following endotoxin with a peak at 30 min and declined subsequently. 4 patients with acute leukaemia showed no increase of circulating colony formers.

Limitation of excessive myelopoiesis by the intrinsic modulation of macrophage-derived prostaglandin E

The clonal proliferation of the committed granulocyte-macrophage stem cell is controlled by a balance between mutually opposing factors, colony stimulating factor and prostaglandin E, both of monocyte-macrophage derivation. Increases beyond a critical concentration of colony stimulating factor within the local milieu of the mononuclear phagocyte induces the coincident elaboration of prostaglandin E, a self-regulated response which serves to limit the unopposed humoral stimulation of myelopoiesis.

Bacterial stimulation and granulocyte inhibition of granulopoietic factor production

We attempted to determine the effect of live bacteria (Staphylococcus epidermidis) on granulocyte colony-stimulating-factor production by human peripheral blood mononuclear cells (monocytes and lymphocytes) in vitro. Addition of bacteria to mononuclear-cell cultures enhanced colony-stimulating-factor production by these cells, as assayed on both human and mouse bone marrow. Addition of peripheral blood granulocytes to parallel cultures eliminated this enhancement effect, presumably by bacterial removal or inactivation. These data suggest that micro-organisms may have a pivotal role in granulocyte production and maturation by serving as a stimulus to increase colony-stimulating-factor production and also as negative control through their removal by the newly formed granulocytes.

In vitro activation of the in vivo colony-forming units of the mouse yolk sac

Experiments were performed to investigate the presence of colony-forming units (CFU) in the mouse embryonic yolk sac during the developmental period in which the yolk sac is the sole hemopoietic organ. Injection of yolk sac cell suspensions from normal embryos into syngeneic, lethally irradiated adult recipients evoked a very low number of spleen colonies. However, prior cultivation of yolk sacs in vitro caused a dramatic increase in the spleen colony-forming capacity--as high as 84-fold--following 48 hours in culture. The yolk sac origin of the spleen colonies was confirmed by: (a) Chromosomal marker analysis; (b) dose-response analysis; (c) demonstrating that the above colonies were not of endogenous origin induced by the mere injection of grafted cells. We conclude that the yolk sac contains many precursors of colony-forming cells which though undetectable by immediate grafting apparently become activated in culture by an as yet unknown induction process.

Alteration of colony-stimulating factor output, endotoxemia, and granulopoiesis in cyclic neutropenia

Cellular and humoral factors involved in the regulation of granulopoiesis were evaluated in two patients with cyclic neutropenia by utilizing the agar-gel marrow culture technique to serially study marrow granulocytic colony-forming capacity (CFC) and the urinary output of colony-stimulating factor (CSF). CSF output varied inversely with peripheral neutrophil counts and directly with monocyte counts and evidence for infection (endotoxemia and/or staphylococcal abscesses). Following autologous infusion of one patient's plasma obtained during a period of neutropenia, increased urinary excretion of CSF occurred concomitant with increments in both marrow CFC and the proportion of granulocytic progenitor cells in DNA synthesis. Neutrophil periodicity was not altered by the administration of the neutropenic plasma. These findings are consistent with the hypothesis that cyclic neutropenia is caused by a quantitatively decreased entry of stem cells or granulocytic progenitor cells into granulopoiesis.

Serum levels of colony stimulating factor(s) and the growth of bone marrow cells in diffusion chambers

Fluctuations in the body fluids of long-ranged humoral substance(s) capable of stimulating the growth of bone marrow granulocytic and macrophage-like cells in diffusion chamber cultures in vivo, was observed after whole body irradiation of mice. The fluctuation pattern was similar to that of the in vitro colony stimulating factor(s) of the sera of irradiated mice which indicates a relation between in vivo and in vitro active factor(s).

Metallic copper-induced granulocyte exudation in the study of granulocytopoiesis

C3H/HeHa mice implanted with rods of metallic copper (CR) or glass (GR) exudate neutrophil granulocytes and mononuclear cells into the site of rod implant (peritoneal cavity). Exudation in CR mice is substantially greater than in GR animals. In CR mice there is an impressive stimulation of myelopoiesis measured in the femoral marrow subsequent to the initial accumulation in the peritoneal cavity. Serum levels of colony stimulating activity (CSA), an in vitro myeloproliferative stimulating activity, are elevated in such animals, as are femoral marrow agarcolony forming cells (CFC). The procedures is useful to the study of myelopoiesis and myelopoietic regulatory mechanisms.