Ohhara N

Protective effect of recombinant murine granulocyte-macrophage colony-stimulating factor against Pseudomonas aeruginosa infection in leukocytopenic mice.

The effects of recombinant murine granulocyte-macrophage colony-stimulating factor (rmGM-CSF) against Pseudomonas aeruginosa infection in ICR mice were investigated. Mice were treated with cyclophosphamide (CPA) and were then injected intraperitoneally with rmGM-CSF three times daily, beginning on the day after CPA treatment, for 7 days. The number of peripheral blood leukocytes in both CPA- and rmGM-CSF-treated mice and control CPA-treated mice reached a nadir on day 4, when P. aeruginosa was injected intraperitoneally. The administration of rmGM-CSF significantly increased the proportion of survivors among mice infected with a lethal dose of P. aeruginosa. This effect was further analyzed by monitoring sequential changes in leukocyte count and bacterial growth in various organs. The number of bacteria in the peritoneal cavities, peripheral blood samples, and livers of GM-CSF-treated mice decreased to an undetectable level after a transient increase, and the number was significantly lower than that in control mice. In GM-CSF-treated mice, the neutrophil levels in peripheral blood started to increase 5 days after CPA administration and were consistently higher than those in controls. Furthermore, the neutrophils in GM-CSF-treated mice were more mature morphologically. Thus, the prophylactic effect of rmGM-CSF against P. aeruginosa infection may result from a rapid recovery of myelopoiesis and a partial enhancement of mature neutrophil function.

Stimulatory effects of bestatin on human B-cell colony formation

Bestatin, (2S, 3R)-3-amino-2-hydroxy-4-phenylbutyryl-L-leucine, is a small molecular immunomodifier. Effects of this compound on human immune function were studied, in vitro, using the human B-cell colony formation technique. B-cell colonies were obtained from enriched B-cell populations placed in conditioned methylcellulose medium containing stimulators and irradiated T-cells as feeders. Addition to the culture of Bestatin at concentrations of 0.1 microgram/ml and 1 microgram/ml led to a significant increase (P less than 0.05) in the number of B-cell colonies and this effect was abolished when irradiated T-cells were not added to the culture. Bestatin increased soluble factor production induced by phytohemagglutinin (PHA)-stimulated T-cells. Such findings suggest that T-cells probably mediate this stimulatory effect of Bestatin on B-cell colony formation.

Treatment of four patients with myelodysplastic syndrome with a small dose of aclacinomycin-A☆

The effect of a small dose of aclacinomycin-A (ACR) was examined in two patients with refractory anemia (RA) and two with refractory anemia with excess of blasts in transformation (RAEB-t). ACR (7 or 14 mg/m2) was given for 10 days in a 2-h per day drip infusion. Clinical symptoms and laboratory data improved in 3 of these 4 patients. In a patient with RA, marked increase in reticulocytes and elevation of the hemoglobin level from 6 to 9 g/dl was observed after two courses of ACR therapy. In two with RAEB-t, Auers rod bearing cells disappeared in the bone marrow and megaloblastic change of the erythroblasts was diminished in one patient. Hemoglobin levels rose from 4.7 to 10 g/dl in one, and platelets and WBC increased in another. No effect was seen in a patient with RA. The cytoreductive effect of ACR was minor compared to the therapy with small dose of cytosine arabinoside (Ara-C). Therefore, ACR warrants further consideration for the treatment of patients with MDS.

Granulocyte-macrophage colony formation in vitro using human non-phagocytic bone marrow cells

SummaryA technique employing silica particles was used to remove cells producing endogenous colony-stimulating factor (CSF) to allow measurement of the level of colony-forming units in culture (CFU-C) in human bone marrow cells. In comparison with the glass-adherence technique, this new approach resulted in a more complete degree of removal of CSF-producing cells and formation of more colonies. This method seems to be useful for performing an accurate assay of exogenous CSF.

Methylcholanthrene-induced murine fibrosarcoma cell line BMT-11 secretes granulocyte colony-stimulating factor

SummaryMurine fibrosarcoma cell line BMT-11 was induced with 3-methyl-cholanthrene and maintained in culture. Transplantation of BMT-11 into syngeneic C57 BL/6 mice produced leukocytosis consisting of marked increments of neutrophils and monocytes associated with massive splenomegaly. In order to elucidate the mechanisms of this leukemoid reaction, we studied the changes occurring in hematopoietic progenitor cells in BMT-11-transplanted mice. The numbers of granulocyte-macrophage colony-forming units (CFU-GM), erythroid colony-forming units (CFU-E), erythroid burst-forming units (BFU-E), and mixed colony-forming units (CFU-Mix) in the spleen showed dramatic 216-fold, 18-fold, 64-fold, and 80-fold increases, respectively, relative to the value in the control mice 5 weeks after the BMT-11 implantation. In contrast, the levels of progenitor cells in the bone marrow remained within normal limits. The nature of the colony-stimulating factor (CSF) secreted from BMT-11 tumor cells was also studied. BMT-11-conditioned medium (BMT-11-CM), BMT-11 tumor extract, and sera from the mice bearing transplanted BMT-11 tumor contained CSF that stimulated mainly granulocyte and macrophage lineages. Furthermore, the expression of the granulocyte colony-stimulating factor (G-CSF) gene in BMT-11 cells were detected by Northern blot analysis.