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CD34+ cell adhesion molecule profiles differ between patients mobilized with granulocyte-colony-stimulating factor alone and chemotherapy followed by granulocyte-colony-stimulating factor.

BACKGROUND: High-dose therapy with autologous peripheral blood progenitor cell support is widely utilized but requires successful CD34+ cell mobilization and collection. Chemotherapy plus growth factors appear to mobilize more CD34+ cells than growth factors alone. Because alterations in expression of adhesion molecules are important in the trafficking of hematopoietic progenitors, the possibility was explored that the mechanism of this superior mobilization may be greater down regulation of adhesion molecules. STUDY DESIGN AND METHODS: The expression of eight adhesion molecules (CD11a, b, and c; 15s; 49d and e; 54; and 62L) on the collected CD34+ cells from 15 patients undergoing mobilization with chemotherapy plus granulocyte-colony-stimulating factor (G-CSF) was compared with those of 14 concomitant patients receiving G-CSF alone. RESULTS: Patients receiving chemotherapy plus G-CSF mobilized more CD34+ cells and did not differ in prior chemotherapy or radiation. There were no significant differences in the percentage of CD34+ cells expressing any of the adhesion molecules examined between the two groups. The chemotherapy plus G-CSF-mobilized cells consistently showed higher expression intensity, and this showed significance or a strong trend for CD11a and c, CD15s, and CD54. Despite these higher expression levels, there were no differences in engraftment kinetics. CONCLUSIONS: CD34+ cells mobilized by chemotherapy plus growth factors appear to have higher intensities of expression of several adhesion molecules. The significance of this observation will require further study.

Adult↗

[Protective effect of human macrophage colony-stimulating factor on fungal infection (2). In vitro effect of human macrophage colony-stimulating factor on systemic aspergillosis and in vitro effect on the activities of macrophage].

We studied the protective effect of human macrophage colony-stimulating factor (M-CSF) of fungal infection due to systemic aspergillosis in normal mice. We also examined the effect of M-CSF against the activities of mouse peritoneal macrophage which were relating to the phagocytosis, the killing, the production of superoxide after contacting with phorbol myristate acetate and the production of nitric oxide after contacting with interferon-gamma in vitro. M-CSF improved the median survival time and the survival rate of systemic aspergillosis. Combination therapy with M-CSF and amphotericin-B (AMPH-B) showed the therapy with either M-CSF or AMPH-B alone. M-CSF enhanced the activities of phagocytosis and the killing of ingested Candida albicans H and spores of Aspergillus fumigatus K by macrophage. Furthermore, M-CSF promoted the production of superoxide and nitric oxide in macrophage. These results indicate that M-CSF can enhance the fungicidal activity of macrophages by activation in vivo, thereby preventing the dissemination of fungal infection.

Amphotericin B↗

Prevention of left ventricular remodeling with granulocyte colony-stimulating factor after acute myocardial infarction: final 1-year results of the Front-Integrated Revascularization and Stem Cell Liberation in Evolving Acute Myocardial Infarction by Granulocyte Colony-Stimulating Factor (FIRSTLINE-AMI) Trial.

BACKGROUND: Experimental and clinical evidence has recently shown that pluripotent stem cells can be mobilized by granulocyte colony-stimulating factor (G-CSF) and may enhance myocardial regeneration early after primary percutaneous coronary intervention (PCI) management of acute myocardial infarction. Sustained or long-term effects of mobilized CD34-positive mononuclear stem cells, however, are unknown. METHODS AND RESULTS: Thirty consecutive patients with ST-elevation myocardial infarction undergoing primary PCI with stenting and abciximab were selected for the study 85+/-30 minutes after PCI; 15 patients were randomly assigned to receive subcutaneous G-CSF at 10 microg/kg body weight for 6 days in addition to standard care including aspirin, clopidogrel, an angiotensin-converting enzyme inhibitor, beta-blocking agents, and statins. In patients with comparable demographics and clinical and infarct-related characteristics, G-CSF stimulation led to sustained mobilization of CD34 positive mononuclear cells (MNC(CD34+)), with a 20-fold increase (from 3+/-2 at baseline to 66+/-54 MNC(CD34+)/microL on day 6; P<0.001); there was no evidence of leukocytoclastic effects, accelerated restenosis rate, or any late adverse events. Within 4 months, G-CSF-induced MNC(CD34+) mobilization led to enhanced resting wall thickening in the infarct zone of 1.16+/-0.29 mm (P<0.05 versus control), which was sustained at 1.20+/-0.28 after 12 months (P<0.001 versus control). Similarly, left ventricular ejection fraction improved from 48+/-4% at baseline to 54+/-8% at 4 months (P<0.005 versus control) and 56+/-9% at 12 months (P<0.003 versus control and paralleled by sustained improvement of wall-motion score index from 1.70+/-0.22 to 1.42+/-0.26 and 1.33+/-0.21 at 4 and 12 months, respectively), after G-CSF (P<0.05 versus baseline and P<0.03 versus controls). Accordingly, left ventricular end-diastolic diameter showed no remodeling and stable left ventricular dimensions after G-CSF stimulation, whereas left ventricular end-diastolic diameter in controls revealed enlargement from 55+/-4 mm at baseline to 58+/-4 mm (P<0.05 versus baseline) at 12 months after infarction and no improvement in diastolic function. CONCLUSIONS: Mobilization of MNC(CD34+) by G-CSF after primary PCI may offer a pragmatic strategy for improvement in ventricular function and prevention of left ventricular remodeling 1 year after acute myocardial infarction.

Abciximab↗

Comparative effects in vivo of recombinant murine interleukin 3, natural murine colony-stimulating factor-1, and recombinant murine granulocyte-macrophage colony-stimulating factor on myelopoiesis in mice.

Purified murine colony-stimulating factors (CSF) recombinant interleukin 3 (IL-3), natural CSF-1, and recombinant granulocyte-macrophage (GM) CSF were assessed in vivo for their effects on BDF1 mouse bone marrow and spleen granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) progenitor cells in untreated mice and in mice pretreated with purified iron-saturated human lactoferrin (LF). The CSF and LF preparations did not contain detectable endotoxin (less than 0.1 ng). Mice pretreated with LF were more sensitive to the effects of CSF. In mice pretreated with LF, 2,000 U IL-3 or 20,000 U CSF-1 significantly enhanced the cycling status and absolute numbers of all progenitors, whereas 20,000 U GM-CSF significantly increased the cycling status of CFU-GM and CFU-GEMM, but had no effect on cycling of BFU-E or on numbers of any of the progenitors. The effects of CSF in mice pretreated with LF were not mimicked by 0.1-100 ng E. coli lipopolysaccharide.

Animals↗

Functional analysis of human hematopoietic repopulating cells mobilized with granulocyte colony-stimulating factor alone versus granulocyte colony-stimulating factor in combination with stem cell factor.

Using in vitro progenitor assays, serum-free in vitro cultures, and the nonobese diabetic/severe combined immune-deficient (NOD/SCID) ecotropic murine virus knockout xenotransplantation model to detect human SCID repopulating cells (SRCs) with multilineage reconstituting function, we have characterized and compared purified subpopulations harvested from the peripheral blood (PB) of patients receiving granulocyte colony-stimulating factor (G-CSF) alone or in combination with stem cell factor (SCF). Mobilized G-CSF plus SCF PB showed a 2-fold increase in total mononuclear cell content and a 5-fold increase in CD34-expressing cells depleted for lineage-marker expression (CD34(+)Lin(-)) as compared with patients treated with G-CSF alone. Functionally, G-CSF plus SCF-mobilized CD34(+)CD38(-)Lin(-) cells contained a 2-fold enhancement in progenitor frequency as compared with G-CSF-mobilized subsets. Despite enhanced cellularity and progenitor capacity, G-CSF plus SCF mobilization did not increase the frequency of SRCs as determined by limiting dilution analysis by means of unfractionated PB cells. Purification of SRCs from these sources demonstrated that as few as 1000 CD34(+)CD38(-)Lin(-) cells from G-CSF-mobilized PB contained SRC capacity while G-CSF plus SCF-mobilized CD34(+)CD38(-)Lin(-) cells failed to repopulate at doses up to 500 000 cells. In addition, primitive CD34(-)CD38(-)AC133(+)Lin(-) cells derived from G-CSF plus SCF-mobilized PB were capable of differentiation into CD34-expressing cells, while the identical subfractions from G-CSF PB were unable to produce CD34(+) cells in serum-free cultures. Our study defines qualitative and quantitative distinctions among subsets of primitive cells mobilized by means of G-CSF plus SCF versus G-CSF alone, and therefore has implications for the utility of purified repopulating cells from these sources.

Animals↗

Use of granulocyte colony-stimulating factor before, during, and after fludarabine plus cytarabine induction therapy of newly diagnosed acute myelogenous leukemia or myelodysplastic syndromes: comparison with fludarabine plus cytarabine without granulocyte colony-stimulating factor.

PURPOSE: To determine whether granulocyte colony-stimulating factor (G-CSF) administered before, during, and after fludarabine plus cytarabine (ara-C; FA) chemotherapy affected complete response (CR) rate, infection rate, blood count recovery, or survival in patients with newly diagnosed acute myelogenous leukemia (AML) or myelodysplastic syndromes (MDS). PATIENTS AND METHODS: A total of 112 patients with newly diagnosed AML (n = 69) or MDS (n = 43) received G-CSF 400 micrograms/m2/d 1 day before (presenting WBC count < 50,000/microL) and/or during (all patients) fludarabine 30 mg/m2/d and ara-C 2 g/m2/d for 5 days (FLAG). G-CSF continued until a CR was achieved. Results were compared with those in 85 newly diagnosed patients (54 AML, 31 MDS) previously treated with FA without G-CSF. RESULTS: Patients in both groups were relatively old (median age of all patients, 63 years), and were likely to have prognostically unfavorable cytogenetic abnormalities (36% had abnormalities of chromosomes 5 and 7 [-5/-7]). G-CSF accelerated recovery to > or = 1,000 neutrophils (P < .0001; median, 34 days for FA, 21 days for FLAG), but logistic regression provided no evidence that the CR rate was higher with FLAG than with FA (P = .50), with unadjusted CR rates of 63% and 53%, respectively. This may reflect relatively high rates of death before neutrophil recovery in both groups. Rates of infection were similar in both groups. The follow-up duration in remission is short, and much of these data remain censored. To date, survival is similar with FA and FLAG. CONCLUSION: On average, G-CSF before, during, and after FA had no effect on CR or infection rates in this population, in which elderly patients and poor prognostic factors were prevalent. The use of FA and laminar airflow rooms rather than more usual therapy needs to be considered when analyzing the results.

Aged↗

Granulocyte-macrophage colony-stimulating factor/interleukin-3 fusion protein versus granulocyte-macrophage colony-stimulating factor after autologous bone marrow transplantation for non-Hodgkin's lymphoma: results of a randomized double-blind trial.

PURPOSE: A phase III trial to compare PIXY321 with granulocyte-macrophage colony-stimulating factor (GM-CSF) following high-dose therapy and autologous bone marrow transplant (ABMT) was conducted to evaluate the time to hematopoietic recovery. PATIENTS AND METHODS: One hundred seventy-seven patients with non-Hodgkin's lymphoma (NHL) receiving ABMT were randomized to receive either PIXY321 750 micrograms/m2/d divided into two subcutaneous (SC) doses or GM-CSF 250 micrograms/m2/d as a 2-hour intravenous (IV) infusion starting on day 0 post-ABMT for a maximum of 28 days. RESULTS: The median time to reach an absolute neutrophil count (ANC) > or = 500/microL in the PIXY321 group was 17 days versus 19 days in the GM-CSF group (P = .07) and the median time to reach platelet transfusion independence in the PIXY321 group was 25 days versus 23 days in the GM-CSF group (P = .30). The toxicity profiles of the two agents appeared to be equivalent with the exception of more patients in the PIXY321 group with a rash (64%) compared with the GM-CSF group (48%) (P = .028). A logistic regression model identified the use of a non-total-body irradiation (TBI) regimen and/or receipt of unpurged marrow and a body-surface area greater than 2.0 m2 as predictive of faster neutrophil engraftment, and those three factors, as well as the receipt of < or = two prior chemotherapy regimens as predictive for rapid platelet engraftment. CONCLUSION: There was a trend toward a slight improvement in neutrophil engraftment post-ABMT with the PIXY321 administered by an SC route compared with GM-CSF administered by an IV route. However, no differences could be identified between the two agents with respect to the time to platelet transfusion independence. Patient, regimen, and graft characteristics were most predictive of the engraftment tempo.

Adolescent↗

Effect of interleukin-11 with and without granulocyte colony-stimulating factor on in vivo neonatal rat hematopoiesis: induction of neonatal thrombocytosis by interleukin-11 and synergistic enhancement of neutrophilia by interleukin-11 + granulocyte colony-stimulating factor.

IL-11, a new hematopoietic cytokine isolated from primate stromal cells (PU-34), has been shown to act synergistically with IL-3 to induce proliferation of early hematopoietic stem cells and induce in vitro CFU-MEG proliferation. We hypothesize that recombinant human (rh)IL-11 alone or in combination with granulocyte colony-stimulating factor (G-CSF) might modulate newborn in vivo granulopoiesis and thrombopoiesis. Newborn Sprague-Dawley rats were given 14 d of intraperitoneal rhIL-11 (0-250 micrograms/kg x 14 d), rhIL-11 (250 micrograms/kg) + rhG-CSF (5 micrograms/kg simultaneously x 14 d), rhIL-11 x 7 d followed by G-CSF x 7 d, G-CSF x 14 d, PBS/human serum albumin x 7 d followed by G-CSF x 7 d, or PBS/human serum albumin x 14 d. rhIL-11 alone had no effect on the circulating hematocrit or absolute neutrophil count. There was, however, a significant increase in the circulating platelet count after rhIL-11 (100 and 250 micrograms/kg) versus PBS/human serum albumin (d 13: 1241 +/- 54, 1262 +/- 58 versus 939 +/- 38 k/mm3; p = 0.01). Sequential and simultaneous IL-11 + G-CSF caused a significant increase in the marrow neutrophil reserve and the circulating absolute neutrophil count above that observed when G-CSF alone was administered. IL-11 +/- G-CSF, however, failed to reduce the 96-h mortality rate during experimental group B streptococcal sepsis. These data suggest that IL-11 alone results in a significant elevation in the blood platelet concentration and, in combination with G-CSF, induces an increase in in vivo neonatal rat myelopoiesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Establishment of radioimmunoassay for human macrophage colony-stimulating factor using recombinant human macrophage colony-stimulating factor as tracer and immunogen.

A sensitive and reliable radioimmunoassay (RIA) for human macrophage colony-stimulating factor (M-CSF) was developed using recombinant human M-CSF (rhM-CSF) as tracer and immunogen. The assay was quantitative over the range of 50 pg/ml and 5.0 ng/ml for M-CSF in human urine and serum, and more sensitive and specific than the murine bone marrow assay. The average level of human M-CSF in urine from normal males (N = 71) and females (N = 46) was 3.94 +/- 1.78 ng/ml (2.85 +/- 1.15 micrograms/g creatinine), and 3.53 +/- 1.70 ng/ml (3.31 +/- 1.12 micrograms/g creatinine), respectively. The serum levels were 1.95 +/- 0.38 ng/ml for males (N = 117), and 1.93 +/- 0.49 ng/ml for females, (N = 16). The results with the urine and sera showed that there was no difference in the M-CSF levels due to age or gender.

Blotting, Western↗

Granulocyte colony-stimulating factor serum and urine concentrations in neutropenic neonates before and after intravenous administration of recombinant granulocyte colony-stimulating factor.

BACKGROUND: Recombinant granulocyte colony-stimulating factor (rG-CSF) has been suggested as a treatment for certain varieties of neonatal neutropenia, but little is known about the pharmacologic disposition of rG-CSF in that population. METHODS: Ten neutropenic neonates were treated with rG-CSF, 10 micrograms/kg intravenously once daily for 3 to 5 days. Serum and urine samples were obtained before rG-CSF dosing and at intervals thereafter for G-CSF quantification by enzyme-linked immunosorbent assay. RESULTS: Five of the neutropenic neonates (termed group 1) were not infected but likely had hyporegenerative neutropenia (4 were born after pregnancy-induced hypertension/intrauterine growth restriction, and 1 had Rh hemolytic disease). Five other infants (group 2) had neutropenia accompanying bacterial sepsis and shock. Before receiving the first dose of rG-CSF, endogenous G-CSF serum and urine concentrations were relatively low in group 1, averaging 130 pg/mL (range: 48-209) in serum and 53 pg/mL (range: 15-141) in urine. Serum concentrations immediately before the final dose were much higher (range: 81-24 835 pg/mL), whereas urine concentrations were unchanged (range: <7 pg/mL-126 pg/mL). In group 2 patients, before receiving the first-dose of rG-CSF, endogenous concentrations were very high, averaging 59 575 pg/mL (range: 20 028-98 280) in serum and 3189 pg/mL (range: 23-4770) in urine. Predose serum concentrations before the final dose (range: 427-14 460 pg/mL) were lower than before the first dose. The area under the concentration curve after the first dose of rG-CSF administration in group 1 was significantly lower than after the first dose in group 2, but no difference in area under the concentration curve was observed between groups 1 and 2 after the last dose of rG-CSF. SPECULATION: The principal means of clearing G-CSF from the serum is by saturable binding to specific G-CSF receptors (G-CSF-Rs). Therefore, the very high G-CSF serum and urine concentrations of group 2 patients before the first rG-CSF dose implies that their G-CSF-Rs were saturated before the dose was given. We speculate that if G-CSF-Rs are saturated with endogenous G-CSF, treatment with rG-CSF will add little or nothing to the granulocytopoietic effort. On this basis, we judge that neonates with septic shock and neutropenia are unlikely to derive benefit from rG-CSF administration.

Enzyme-Linked Immunosorbent Assay↗

Immunization with recombinant human granulocyte-macrophage colony-stimulating factor as a vaccine adjuvant elicits both a cellular and humoral response to recombinant human granulocyte-macrophage colony-stimulating factor.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is an important cytokine for the generation and propagation of antigen-presenting cells and for priming a cellular immune response. We report here that use of recombinant human GM-CSF (rhGM-CSF), administered as an adjuvant in a peptide-based vaccine trial given monthly by intradermal injection, led to the development of a T-cell and antibody response to rhGM-CSF. An antibody response occurred in the majority of patients (72%). This antibody response was not found to be neutralizing. In addition, by 48-hour delayed type hypersensitivity (DTH) skin testing, 17% of patients were shown to have a cellular immune response to the adjuvant rhGM-CSF alone. Thymidine incorporation assays also showed a peripheral blood T-cell response to rhGM-CSF in at least 17% of the patients. The generation of rhGM-CSF-specific T-cell immune responses, elicited in this fashion, is an important observation because rhGM-CSF is being used as a vaccine adjuvant in various vaccine strategies. rhGM-CSF-specific immune responses may be incorrectly interpreted as antigen-specific immunity, particularly when local DTH responses to vaccination are the primary means of immunologic evaluation. We found no evidence of hematologic or infectious complications as a result of the development of rhGM-CSF-specific immune responses.

Adjuvants, Immunologic↗

Granulocyte colony-stimulating factor receptors on human acute leukemia: biphenotypic leukemic cells possess granulocyte colony-stimulating factor receptors.

Granulocyte colony-stimulating factor (G-CSF) receptors on the gated leukemic blast cells from newly diagnosed patients with acute leukemia or crisis of chronic myelogenous leukemia were investigated using flow cytometric detection. Surface marker analysis and cytochemical studies were conducted simultaneously to characterize the blast cells. Among 24 leukemia cases examined, G-CSF receptor-positive blast cells were detected in all 11 cases of acute myeloblastic leukemia even though the percentage range of positive cells was widely variable. On the other hand, they were not detected on the blast cells from patients with peroxidase-negative acute lymphoblastic leukemia with no myeloid surface antigens. However, G-CSF receptors were demonstrated in significant amounts on blast cells from 5 of 8 cases of peroxidase-negative acute leukemia expressing both myeloid and lymphoid surface antigens (biphenotypic leukemia). The percentage of blast cells positive for G-CSF receptors was significantly smaller in biphenotypic cases [33 +/- 14% (SD)] than in acute myeloblastic leukemia cases [65 +/- 22%] (P less than 0.01). The percentage expression of CD13 antigen by blast cells was significantly related to their percentage positivity for G-CSF receptors (rs = 0.50, P less than 0.05). These findings indicate that the distribution of flow cytometrically detectable G-CSF receptors on leukemic cells possessing myeloid characteristics may be related to the maturation process.

Antigens, CD↗

Pharmacokinetic and pharmacodynamic comparisons between human granulocyte colony-stimulating factor purified from human bladder carcinoma cell line 5637 culture medium and recombinant human granulocyte colony-stimulating factor produced in Escherichia coli.

The pharmacokinetics and biological activities of recombinant human granulocyte colony-stimulating factor (hG-CSF) produced in Escherichia coli were compared with those of hG-CSF purified from human bladder carcinoma cell line 5637 culture medium (5637-hG-CSF). Recombinant hG-CSF was biologically active in a bone marrow cell proliferation assay in vitro, with a dose-response curve similar to that of 5637-hG-CSF. The effects of 5637- and recombinant hG-CSF administered via i.v. injection to rats showed similar response patterns of neutrophil counts in peripheral blood. From these results, it is concluded that the O-linked sugar chain of hG-CSF does not contribute to the in vitro and in vivo biological activities. The pharmacokinetics of both forms of hG-CSF in rats were investigated using a sandwich enzyme-linked immunosorbent assay. After i.v. administration, the serum concentration-time curves of 5637- and recombinant hG-CSF declined biexponentially. Total body clearance and steady-state volume of distribution of 5637-hG-CSF were smaller than those for the recombinant form. After s.c. administration, a lower peak serum level, smaller AUC, and lower bioavailability of 5637-hG-CSF were observed compared to recombinant hG-CSF.

Animals↗

Serum colony-stimulating and colony-inhibitory activity in response to neutropenia.

Since sera from most species contain both colony-stimulating and column-inhibitory factors, the net CSA results from a balance between these opposing substances. Studies were performed to determine whether the increased CSA noted during neutropenia or endotoxemia is due to an increase in CSF or to a decline in serum inhibitors. Rats were treated with cyclophosphamide, total body irradiation, or endotoxin and bled during the peak CSA response. By separation studies using Sephadex G150, it was shown that serum levels of high-molecular-weight inhibitors were unchanged from control values. Minimal CSA was detected in normal serum fractions; increased activity was found in fractions from neutropenic animals. During a postcyclophosphamide rebound neutrophilia, serum CSA was undetectable; inhibitor levels were similar to those measured in untreated controls. These observations show that the increased serum CSA seen with neutropenia is due to a true increase in CSF and not to a decline in circulating inhibitors.

Agranulocytosis↗

Independent regulation of granulocyte-macrophage colony-stimulating factor and multi-lineage colony-stimulating factor production in T lymphocyte clones.

When murine T lymphocyte clones were cultured with purified recombinant IL 2, a dose-dependent increase in the production of granulocyte-macrophage colony-stimulating factor (GM-CSF) was observed. Whereas these clones produced both GM-CSF and multi-lineage CSF (multi-CSF) when cultured with concanavalin A, IL 2 induced the production of GM-CSF in the virtual absence of detectable multi-CSF. In addition, IL 2 synergistically enhanced the production of both GM-CSF and multi-CSF by some antigen- or Con-A-stimulated clones. Like Con-A-induced CSF production, GM-CSF production in the presence of IL 2 required protein synthesis but could occur in the absence of proliferation by the clone. Analysis of dose-response curves for stimulation of CSF production by Con A in the presence and absence of IL 2 suggested that Con A and IL 2 activated GM-CSF synthesis by different mechanisms. These results indicate that the coordinate production of two factors by a single T cell clone stimulated with Con A can be dissociated when the clone is stimulated with IL 2.

Animals↗

Taxol induces the hematopoietic growth factor granulocyte-macrophage colony-stimulating factor in murine B-cells by stabilization of granulocyte-macrophage colony-stimulating factor nuclear RNA.

Taxol, a microtubule-stabilizing agent, has been shown to have antineoplastic activity against various tumors. In addition, it has been shown that taxol resembles bacterial lipopolysaccharide in its ability to activate macrophages. Recently we have shown that lipopolysaccharide induces the expression of the granulocyte-macrophage colony-stimulating factor (GM-CSF) in murine B-cell lines. In light of the similarity of taxol and lipopolysaccharide in their effects on macrophages, we tested whether taxol could also induce the expression of GM-CSF in B-cell lines. In the present study we used the murine B-lymphoma cell line M12.4.1. In unstimulated cells, no GM-CSF mRNA was detected, whereas in taxol-stimulated stimulated cells at a concentration of 30 microM, GM-CSF mRNA was induced 4-8 h after stimulation. This induction of GM-CSF mRNA was down-regulated by 10 ng/ml of interleukin 4. Actinomycin D chase experiments revealed that interleukin 4 did not affect the half-life of the taxol-induced GM-CSF cytoplasmic mRNA, nor did it alter GM-CSF gene transcription. Polymerase chain reaction analysis of nuclear RNA, utilizing probes specific for sequences in the first intron of GM-CSF, indicated that taxol enhances accumulation of nuclear precursor RNA and that interleukin 4 decreases this accumulation. The present study shows a novel activity of taxol in inducing the release of the hematopoietic growth factor GM-CSF from B-cells. Since GM-CSF is known to recruit macrophages and enhance their cytotoxicity against tumor cells, our observations suggest that part of the known antitumor activity of taxol may be due to synergistic effects of GM-CSF activity together with direct cytotoxic actions through microtubule stabilization.

Animals↗

The role of macrophage colony-stimulating factor in hepatic glucan-induced granuloma formation in the osteopetrosis mutant mouse defective in the production of macrophage colony-stimulating factor.

To elucidate the effects of macrophage colony-stimulating factor (M-CSF) on Kupffer cells and monocyte/macrophages in hepatic granuloma formation, we examined granulomas produced by glucan injection in the liver of osteopetrotic mice and littermates with or without M-CSF administration. In the osteopetrotic mice, monocytes were deficient in peripheral blood, and their number did not increase after glucan injection. Hepatic granulomas were formed in the osteopetrotic mice by glucan injection without a supply of blood monocytes. During this process, M-CSF-independent Kupffer cells proliferated, particularly before the granuloma formation, clustered in the hepatic sinusoid, and transformed into epithelioid cells and multinuclear giant cells. In the M-CSF-treated osteopetrotic mice, glucan injection induced an increase in the number of blood monocytes and formed hepatic granulomas at a nearly similar degree to that of littermate mice. Thus, it is concluded that neither monocytes nor M-CSF are necessary for granuloma formation. In contrast, Kupffer cells play a crucial role as granulomas develop in M-CSF-uninjected osteopetrotic mice.

Animals↗