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Biomedical subjects

F R Seiler

Publications and source records attributed to F R Seiler.

At least 19 recordsLinked to original sources
PubMed1992

Myelosuppressive effects of cytosine arabinoside (Ara-C) on growth factor-dependent human long-term bone marrow cultures (LTBMC).

Freshly isolated human mononuclear cells (5 x 10(6)) were incubated in a Dexter-type long-term bone marrow culture (LTBMC) system to study myelosuppressive effects of cytosine arabinoside (Ara-C) in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin 3 (IL-3). Differential counts (dc) of the nonadherent cell (nac) populations, starting with culture initiation, were performed weekly. After one week of simultaneous incubation of LTBMCs with either cytokine (100 ng/ml) and Ara-C (1 microgram/ml), nac numbers were markedly reduced compared to controls. Dc after week 1 of culture demonstrated significant decreases of all myeloid cell fractions except for macrophages, which remained unaffected. Growth factor-dependent LTBMCs exposed to Ara-C showed recovery of promyelocytic, metamyelocytic, and polymorphonuclear cell numbers up to control values (cultures without Ara-C exposure) in weeks 3 to 6. Intriguingly, high-proliferative, early myeloid progenitor cells (myeloblasts) appeared at high rates only in IL-3-dependent LTBMCs with and without Ara-C exposure. Nac numbers in LTBMCs exposed to Ara-C alone declined rapidly; after two weeks of culture only negligible numbers of viable nac were maintained. Plating experiments of nac in the presence of GM-CSF were performed weekly. Granulocyte-macrophage colony-forming units (CFU-GM) yields for nac from IL-3 LTBMCs were consistently higher than those for nac from GM-CSF LTBMCs. Ara-C exposure reduced CFU-GM numbers generated with nac from GM-CSF LTBMCs to 10% of GM-CSF controls (week 1). However, CFU-GM numbers grown with nac from Ara-C exposed GM-CSF-dependent LTBMCs recovered above control levels after week 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Haematological effects of rhGM-CSF in dogs exposed to total-body irradiation with a dose of 2.4 Gy.

It was the specific aim of this study to test the stimulatory effects of recombinant human GM-CSF (rhGM-CSF) on haemopoietic regeneration in dogs which had received total-body irradiation (TBI) with a dose of 2.4 Gy. In normal dogs rhGM-CSF given subcutaneously at 10 microgram/kg per day or 30 microgram/kg per day for 21 days caused strong but transient increases in the peripheral blood neutrophils. The monocyte counts also showed a transient rise during treatment in a dose-dependent fashion, whereas the lymphocyte counts increased only at the higher dose of rhGM-CSF and the platelet counts were transiently depressed during the course of the treatment. In the irradiated animals treatment with rhGM-CSF decreased the severity and shortened the duration of neutropenia but had no significant influence on monocyte or lymphocyte recovery. The granulocyte values showed a characteristic pattern of fluctuations with the first peak occurring at the same time (day 10 to day 13) when the abortive rise was observed in the untreated dogs. In contrast the GM-CFC in the peripheral blood remained depressed during the whole treatment course, similar to the untreated irradiated controls. These results indicate that treatment with GM-CSF can be an effective biological monotherapy for radiation-induced bone marrow failure, but that for higher radiation doses the number of GM-CSF responsive target cells will become a critical determinant of therapeutic efficacy.

Animals↗
PubMed1991

Comparative analysis of the influences of IL-1, IL-3 and GM-CSF on the commitment of granulocyte-macrophage progenitors in vitro.

Our experiments were directed towards the detection of the influence of interleukin-1 (IL-1); interleukin-3 (IL-3), and granulocyte-macrophage colony-stimulating factor (GM-CSF) on the generation of granulocyte-macrophage progenitor cells. We also set out to examine whether this process is connected with changes within the early precursor cell compartment. Bone marrow suspension cultures (12 days) supplemented with these cytokines were tested for the presence of GM colony-forming cells (GM-CFC) in a colony-forming unit assay. The percentage of CD34+ and HLA-DR+ as well as the number of blasts and promyelocytes were estimated cytofluorometrically and morphologically. The proliferative effect of GM-CSF was associated with a net increase of GM-CFC and HLA-DR+ myeloid cells and a decrease in the percentage of CD34+ early precursor cells. IL-3 acted similarly and also caused an absolute decrease of CD34+ cells in the cultures. IL-1 did not stimulate the generation of blasts or GM-CFC but elevated the number of CD34- as well as HLA-DR-expressing cells in the cultures. These results imply that GM-CSF supported the maintenance of hematopoiesis in vitro. The transition from early precursor cells to committed myeloid progenitor cells (GM-CFC) and more mature precursor cells (G-CFC, M-CFC) may be supported by GM-CSF without affecting the self-renewing capacity of CD34+ early precursors. In contrast, the blast-generating and proliferation-inducing action of IL-3 is associated with a drop in the total number of CD34+ stem cells. An efficient renewal of this population obviously depends on the presence of IL-1.

Antigens, CD↗
PubMed1991

15-Deoxyspergualin (15-DOS) has a curative effect on the development of SLE-like autoimmune disease in MRL/1 mice.

Treating MRL/1pr mice, which spontaneously develop systemic lupus erythematosus and rheumatoid arthritis, with 15-DOS resulted in a decrease in the amount of autoantibodies and inhibited proteinuria of the developing glomerulonephritis with an improved survival rate of these autoimmune mice. 15-DOS treatment also lowered the percentage of animals with swollen lymph nodes and inhibited the development of splenomegaly. In the established disease 15-DOS returned urine-protein values and renal function (serum urea and creatinine) to normal levels. Circulating rheumatoid factor and autoantibodies to double-stranded DNA were reduced and the increase in paw volume (signs of a polyarthritis) was inhibited.

Animals↗
PubMed1991

15-Deoxyspergualin (15-DOS) for therapy in an animal model of multiple sclerosis (MS): disease modifying activity on acute and chronic relapsing experimental allergic encephalomyelitis (EAE).

We examined the therapeutic effect of 15-DOS in the two models of acute and chronic relapsing EAE in Lewis rats. In the first model adult rats developed an acute severe EAE and by day 16 all animals died. Lewis rats treated with 15-DOS showed a delayed and reduced onset of clinical symptoms and mortality was prevented. In the second model Lewis rats (aged animals) developed a chronic relapsing EAE with up to three relapses. The second and third episodes were both milder and shorter in duration. All animals treated with 15-DOS survived the delayed first attack and developed no further relapses.

Acute Disease↗
PubMed1991

Inhibitory effects of the anti-rat T-cell receptor (TCR) monoclonal antibody (MAb) R73 on various experimental autoimmune diseases.

The anti-rat alpha/beta-TCR, MAb-R73 has been investigated as to its disease modifying activity on adjuvant arthritis (AA), on experimental allergic encephalomyelitis (EAE) and on a local graft versus host (GvH) reaction (popliteal lymph nodes = PLN) in Lewis or Brown-Norway rats. R73 was able to prevent the onset of the AA and even if therapy started after the establishment of AA the MAb was still able to reduce the degree of chronic inflammation and arrest its progress. Intravenous MAb-R73 application also reduced the signs of EAE and prevented mortality. This was even seen when the substance was given after the outbreak of the clinical symptoms or when the F(ab)2 fragment of this MAb was used. Also in the model of local GvH reaction R73 acted therapeutically and lowered the PLN weights.

Animals↗
PubMed1991

A rabies-specific human monoclonal antibody that protects mice against lethal rabies.

According to a recommendation from WHO (World Health Organisation) for prevention of a possible rabies infection, active vaccination has to be combined with application of immunoglobulin to get a fast protective effect. At present, preparations of purified human or equine rabies-specific immunoglobulin are used. We have generated a human rabies-specific monoclonal antibody (huMAb) by immortalization of human B-cells with Epstein Barr Virus (EBV), followed by fusion with a mouse myeloma cell. The resulting clone TW-1 secrets an IgG1 lambda huMAb which specifically reacts in ELISA with 5 laboratory rabies virus strains of serotype 1 and DUV3 (Duvenhage, serotype 4). Western Blot analysis revealed fine specificity for the G glycoprotein (gp67) of rabies virus. HuMAb TW-1 neutralizes rabies virus in vitro (RFFIT) as well as in vivo and protects rabies infected mice. Compared to polyclonal human rabies immunoglobulins, huMAb TW-1 is advantageous, because of its defined specificity and the very low amounts of total protein needed for therapeutic effects.

Animals↗
PubMed1991

Combined effects of granulocyte-macrophage colony stimulating factor with erythropoietin in subhuman primates.

Recently, we showed in a cynomolgus monkey model that the combination of interleukin-3 (IL-3) and granulocyte-macrophage colony stimulating factors (GM-CSF) demonstrates synergistic effects, if administered sequentially. Not only were progenitor cells of the myelocytic lineage stimulated cooperatively, but platelet release was also observed. These effects could not be found using these factors alone. In this study, GM-CSF was administered with erythropoietin (EPO) in a sequential manner. This treatment of GM-CSF and EPO resulted in a GM-CSF-stimulated increase in cells of myelomonocytic differentiation, and enhanced stimulation of erythroid and megakaryocytic lineages. The observed effects of growth factor combination were seen to the same extent with intravenous or subcutaneous administration. The results obtained may predict the potential usefulness of GM-CSF treatment together with EPO. This could improve the effectiveness of single growth factors in only limited indications, e.g., reduced need for transfusion (platelets, blood), correction of iatrogenic anemia, and recovery from myelosuppression due to chemo- and radiotherapeutic agents.

Animals↗
PubMed1991

Effect of granulocyte-macrophage colony-stimulating factor on the induction of unresponsiveness by lymphoid cells.

Skin grafts can be significantly prolonged in ALS-treated mice by the injection of 25 x 10(6) donor bone marrow cells or 50 x 10(6) spleen cells. Lymph node cells and thymocytes are only minimally effective in prolonging grafts. The effect of a hematopoietic growth factor, granulocyte-macrophage colony stimulating factor (GM-CSF) was studied in this model of unresponsiveness. C3H/He lymphoid cell donors were treated with GM-CSF. Either normal or GM-CSF-treated cells were injected into ALS-treated B6AF1 mice grafted with C3H/He skin. GM-CSF treatment significantly augmented the effect of marrow in prolonging graft survival at doses of 1 to 25 x 10(6) cells. In contrast, GM-CSF had no effect on the graft-prolonging effect of spleen cells when 50 x 10(6) cells were given. When the dose of cells was reduced to 25 x 10(6), graft survival in the group given GM-CSF-treated cells was prolonged compared with survival in the group given normal cells. Grafts in the group given GM-CSF-treated lymph node cells were rejected in sensitized fashion. When marrow and spleen are separated on a Percoll gradient, the cell active in promoting graft survival is recovered primarily in the 52.5% fraction. The graft-prolonging effect of the 52.5% marrow fraction was not affected by GM-CSF treatment. In contrast, GM-CSF-treated marrow cells in the 60% fraction significantly prolonged graft survival, while normal marrow cells in this fraction had no effect on graft survival. GM-CSF-treated spleen cells in the 52.5% and 60% fractions significantly decreased graft survival compared with normal cells when given at a dose equal to the number of cells recovered from 50 x 10(6) cells. When the dose of fractionated spleen cells was reduced, GM-CSF-treated spleen cells were more effective than normal cells in prolonging graft survival. These results indicate that GM-CSF activates a cell in marrow that promotes graft survival. This cell is recovered in the 60% Percoll fraction. In contrast, GM-CSF appears to affect two cell populations in spleen, one beneficial and one detrimental to graft survival. The predominant effect depends on the dose of spleen cells that is given.

Animals↗
PubMed1991

Studies on the efficacy of mast cell growth factor (c-kit ligand) in vitro as well as in vivo.

We tested the ability of recombinant human (rhu) mast cell growth factor (MGF), also known as c-kit ligand, to stimulate the colony formation of human bone marrow cells in semisolid medium alone and in combination with rhu erythropoietin (EPO), rhu Interleukin 3 (IL-3), rhu granulocyte colony stimulating factor (G-CSF) and rhu granulocyte-macrophage colony stimulating factor (GM-CSF). The addition of MGF to cultures containing EPO or EPO + IL-3, GM-CSF and G-CSF, resp., resulted in macroscopic erythroid burst-forming units (BFU-E). Multipotential (colony-forming unit granulocyte, erythroid, monocyte, megakaryocyte [CFU-GEMM]) progenitors were stimulated by MGF in the presence of EPO. Colony-forming unit granulocyte-macrophage (CFU-GM) were activated by MGF only in combination with GM-CSF. The combination of MGF with EPO was used for synergism studies in healthy cynomolgus monkeys. In the chosen concentration MGF alone had no effect on white blood cell (WBC) counts and on platelets, but a slight effect on reticulocytes. EPO by itself increased reticulocyte counts with no effects on WBC or platelets. The combination of both factors resulted in a significant increase of reticulocytes. No other effects were seen. These studies demonstrate the potent synergistic interaction of MGF and other hematopoietic growth factors.

Animals↗
PubMed1991

An enzyme linked immunosorbent assay for the detection of human interleukin 3 in serum.

A sandwich enzyme immunoassay was developed for measuring human Interleukin 3 (IL-3) in human and animal sera. Polyclonal and monoclonal antibodies were raised against the recombinant human protein. These have been used to develop an immunoassay which can detect down to 10 pg/ml of human IL-3. The assay involves a polyclonal rabbit antibody coupled to a solid phase and a mouse monoclonal antibody-horseradish peroxidase conjugate as the detection antibody. Unlike the classical bone marrow assay and other cell line based bioassays for IL-3, the immunoassay was specific for the cytokine showing no or only negligible cross-reactivity with IL-1, IL-2, IL-6, erythropoietin, granulocyte colony-stimulating factor (G-CSF) and GM-CSF. The assay does not exhibit interfering matrix effects when used for the estimation of human IL-3 in serum samples.

Antibodies, Monoclonal↗
PubMed1991

Highly specific and highly sensitive enzyme immunoassays for antibodies to human interleukin 3 (IL-3) and human erythropoietin (EPO) in serum.

Two versatile, rapid, easy-to-perform and highly sensitive enzyme immunoassays (ELISAs) were developed for the detection and quantification of antibodies to human IL-3 and human EPO in serum samples from both man and laboratory animals. These one-step assays are based on the "inverse sandwich" principle, where antibodies present in the sample linked both the solid phase antigen bound to a microtiter plate and the free antigen, which had been covalently coupled to horseradish peroxidase. The limits of detection are lower than those of the neutralization bioassays; antibodies to IL-3 and to EPO were detected at concentrations as low as 2 ng/ml and 5 ng/ml, respectively. No cross-reactivity with related proteins and no interfering matrix effects were observed when used for the estimation of antibodies against rhu IL-3 and rhu EPO in serum samples of various species. Thus both assays were used without modification for the screening of antibodies in serum samples from both man and animal during treatment with these hematopoietic hormones.

Animals↗
PubMed1991

Optimizing autologous blood donation by recombinant human erythropoietin (rhu-EPO) and interleukin 3 (IL-3).

The transfusion of autologous blood protects surgical patients from both the transfusion transmitted diseases (AIDS, posttransfusion hepatitis) and the immunosuppressive effects of homologous blood. Nevertheless, the use of autologous blood is still unsatisfactory, mainly because of the elaborated logistics, organization and technique required and the often insufficient amounts of autologous blood gained. Today, the major growth-factors of erythropoiesis are available as recombinant analogues. In the studies reviewed here, we investigated the effects of rhu-EPO and IL-3 on perioperative erythropoiesis in two canine models of acute isovolemic hemodilution. Different therapeutic concepts are compared with respect to preoperative changes in hematocrit, the volume of autologous blood gained and the duration of postdilutional anemia.

Animals↗
PubMed1991

Bone marrow obtained during hip surgery: a novel source for studies of hemopoiesis in human long-term bone marrow culture (LTBMC).

Studies with human bone marrow cells are often impaired by the poor quality of sternal aspirates due to varying numbers of contaminating blood cells before enrichment procedures and insufficient progenitor cell yields. In this study we report on experiments performed with human bone marrow cells isolated from a) spongiose bone fragments collected during hip surgery in patients with osteoarthritis or b) sternal aspirates. After Ficoll-Histopaque density gradient centrifugation absolute cell numbers were always lower in the samples obtained from sternal aspirates. However, both sources proved to yield the same proportions of the respective myeloid cell populations. Human long-term bone marrow cultures (LTBMC), semi-solid agar assays (CFU-GM day 14), and 3H-thymidine incorporation assays proved the comparability of the two bone marrow sources.

Adult↗
PubMed1991

Development of a rapid, highly sensitive, non-radioactive assay system for hematopoietic growth factors.

The aim of this study was to develop non-radioactive cell line proliferation assays. The human leukemic cell line TF1 (Kitamura et al., 1989) was used for the determination of the specific biological activity of recombinant human (rhu) granulocyte-macrophage colony-stimulating factor (GM-CSF) and rhu Interleukin 3 (IL-3) by a simple and economical fluorometric assay with a sensitivity similar to the measurement of 3H-thymidine uptake. The TF1 cell line responds to rhu IL-3, rhu GM-CSF and to a lesser extent to rhu Erythropoietin (EPO) and mast cell growth factor (MGF), but not to rhu G-CSF. It is dependent upon rhu GM-CSF for survival in culture. For the proliferation assay 1 x 10(4) TF1 cells were incubated with 20 ng - 0.256 pg rhu GM-CSF or rhu IL-3 at 37 degrees C and 5% CO2 in humidified atmosphere. After 48 h the cells were washed twice with PBS and were incubated with 4-Methylumbelliferyl-heptanoate for 60 min. Fluorescence was determined on a Titertek Fluoroskan II (Flow Lab.), and results were given as fluorescence units using a 355 nm excitation filter and a 480 nm emission filter. The developed assay showed an interassay variability lower than 15%. The sensitivity of the proliferation assays in the same range as the thymidine incorporation assays.

Biological Assay↗