Biomedical subjects

F C van Gils

Publications and source records attributed to F C van Gils.

9 recordsLinked to original sources

PubMed1995

Interleukin-3 treatment of rhesus monkeys leads to increased production of histamine-releasing cells that express interleukin-3 receptors at high levels.

To understand the hematopoietic and nonhematopoietic responses to interleukin-3 (IL-3), expression of cell-surface IL-3 receptors (IL-3R) was examined on bone marrow (BM) cells and peripheral blood (PB) cells of rhesus monkeys during the course of in vivo IL-3 treatment. Whereas IL-3R expression is low in untreated monkeys, IL-3 administration led to a gradual increase in both low- and high-affinity binding sites for IL-3. This increase reflected the total number of cells expressing IL-3Rs, as detected by flow cytometry using biotinylated IL-3. Most of these IL-3R+ cells in both BM and PB could be characterized as basophilic granulocytes that contained high levels of histamine. In contrast to the effect on these differentiated cells, IL-3 administration did not significantly alter the low level IL-3R expression on immature, CD34+ cells. Further flow cytometric analysis using biotinylated growth factors showed that the IL-3R+ basophils also expressed receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), but not for IL-6 or Kit ligand. These findings indicated that the IL-3R+ cells included neither monocytes, which express GM-CSFRs and IL-6Rs abundantly, nor mast cells, which express c-kit. By combining flow cytometric and Scatchard data, it was calculated that the basophils contain as many as 1 to 2 x 10(3) high-affinity IL-3Rs and 15 to 30 x 10(3) low-affinity sites. The finding that in vivo IL-3 treatment leads to the production of large numbers of cells that express high levels of IL-3R and are capable of producing histamine provides an explanation for the often severe allergic reactions that occur during prolonged IL-3 administration. It also indicates that IL-3, in addition to its direct effects on hematopoietic cells, may also stimulate hematopoiesis through the release of secondary mediators such as histamine by IL-3-responsive mature cells.

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PubMed1994

Interleukin-3 (IL-3) receptors on rhesus monkey bone marrow cells: species specificity of human IL-3, binding characteristics, and lack of competition with GM-CSF.

The relative affinity of recombinant human interleukin-3 (IL-3) binding to normal rhesus monkey bone marrow cells was found to be 25- to 50-fold less than that of homologous IL-3, which explained the species specificity of human IL-3 observed when tested in Macaca species. In contrast, only a small difference was found between human and rhesus monkey IL-3 in relative binding affinity for receptors on human acute myelogenous leukemia (AML) cells, which confirmed that the species specificity of IL-3 is largely unidirectional. The biological significance of the findings was demonstrated by direct in vivo comparison of the effects of high-dose recombinant rhesus monkey and human IL-3. The binding characteristics of IL-3 receptors on rhesus monkey bone marrow and peripheral blood cells were further characterized by specific binding of radiolabeled rhesus monkey IL-3. Scatchard analysis of two bone marrow samples demonstrated high-affinity IL-3 receptors (25 and 80 sites/cell, respectively; equilibrium dissociation constants [Kd] of 8 and 3 pM/L) as well as low-affinity receptors (1070 and 1290 sites/cell; equilibrium dissociation constants of 2600 and 1200 pM/L). In addition, IL-3 receptor expression was also detected on purified CD34-positive bone marrow cells. Competition by human granulocyte-macrophage colony-stimulating factor (GM-CSF) of IL-3 binding to high- or low-affinity receptors on rhesus monkey peripheral blood and bone marrow cells could not be demonstrated, which may indicate that the growth factor-specific alpha-subunits of the GM-CSF and IL-3 receptors are expressed predominantly on different cell types.

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PubMed1994

Neutralizing antibodies during treatment of homologous nonglycosylated IL-3 in rhesus monkeys.

During administration of homologous nonglycosylated IL-3 to rhesus monkeys, reversal of hematologic effects and disappearance of side effects suggested a neutralizing anti-IL-3 antibody response. Among a total of 20 monkeys treated with IL-3, ELISA of serial serum samples revealed anti-IL-3 antibodies in ten animals. Antibody production tended to be dose dependent. Triplicate subcutaneous injections and i.v. administration provoked earlier appearance of antibodies than single s.c. injection. Prolonged continuous intravenous IL-3 administration (63 and 93 days) at a dose of 1 microgram/kg/day did not result in antibody production. Among a total of eight animals with sufficiently high titers to allow for antibody purification, seven appeared to have generated antibodies that neutralized the biologic activity of IL-3 in vitro. In six monkeys, the response to IL-3 decreased while antibody titers rose, strongly suggesting neutralization of IL-3 in vivo. It is concluded that recombinant, nonglycosylated IL-3 as used in this study may elicit a neutralizing antibody response.

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PubMed1993

Flow cytometric detection of receptors for interleukin-6 on bone marrow and peripheral blood cells of humans and rhesus monkeys.

The expression of receptors for interleukin-6 (IL-6) on human and rhesus monkey peripheral blood and bone marrow (BM) cells was examined by multiparameter flow cytometry after staining with biologically active, biotin-labeled human IL-6 and phycoerythrin-conjugated streptavidin. Consistent with the multiple biologic effects of IL-6 in stimulating immune functions and hematopoiesis, IL-6 receptors were detectable on a wide variety of cell types. In peripheral blood, IL-6 receptors were detectable on monocytes, granulocytes, and on CD4+ T lymphocytes but not on resting, CD19+ B lymphocytes and CD56+ natural killer (NK) cells. CD8+ T lymphocytes also expressed IL-6 receptors but at lower levels than CD4+ cells. The IL-6 receptors on granulocytes were only detectable after staining with high concentrations of biotin-IL-6, suggesting that most IL-6 receptors on these cells represent low-affinity sites. In contrast, IL-6 receptors on both CD4+ and CD8+ T lymphocytes were detectable at biotin-IL-6 concentrations as low as 10 pmol/L, indicating that these cells bind IL-6 with high affinity. IL-6 receptor expression patterns on rhesus monkey and human blood cells were very similar except that receptor levels on granulocytes were lower in humans than in rhesus monkeys. Similar differences in expression levels were observed for IL-6 receptors that were detectable on most granulocyte precursors in the mononuclear fraction of rhesus monkey and human bone marrow. In addition to these relatively mature cell types, IL-6 receptors were detectable on a large fraction of human and rhesus monkey BM blast cells that express the CD34 antigen. The presence of IL-6 receptors on CD34+ BM blast cells, which are the precursor cells of most, if not all, BM-derived blood cells, is consistent with the ability of IL-6, in conjunction with other cytokines, to stimulate immature hemopoietic cells in vitro and to promote blood cell production when administered in vivo.

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PubMed1993

Acute side effects of homologous interleukin-3 in rhesus monkeys.

Interleukin-3 treatment of juvenile rhesus monkeys elicits a dose- and time-dependent syndrome that includes urticaria, palpable lymph nodes, splenomegaly, thrombocytopenia, anemia, vomiting, diarrhea, intestinal bleeding, edema, and arthritis, apart from a strong stimulation of hemopoiesis. Arthritis was found to occur significantly more often in animals expressing the major histocompatibility complex alleles B9 and Dr5. Histological analysis revealed an abundance of mast cells in urticaria and, to a lesser extent, in lungs and synovia of arthritic joints. Active osteoclasts were abundant in ribs and arthritic joints. Extramedullary hemopoiesis was encountered in liver, spleen, and kidneys. The spleen showed deposits of hemosiderin, and in the liver, Kupffer cells were loaded with iron, indicating enhanced turnover of hemoglobin. Lymph nodes and bone marrow showed macrophages involved in hemophagocytosis, which probably contributed to the development of anemia and thrombopenia. Biochemical parameters in sera were indicative of parenchymal liver damage, with cholestasis and increased erythrocyte destruction. The side effects were strongly reduced in monkeys subjected to total body irradiation just before interleukin-3 treatment. Histamine antagonists were not significantly effective in preventing side effects, which is explained by the perpetual stimulation of basophilic granulocytes by exogenous interleukin-3. The nature of the side effects indicates that interleukin-3 may be involved in the pathogenesis of acute type hypersensitivity reactions and arthritis.

Anemia↗

PubMed1993

Pharmacokinetic basis for optimal hemopoietic effectiveness of homologous IL-3 administered to rhesus monkeys.

To design an interleukin-3 (IL-3) administration schedule for optimal hemopoietic effectiveness, serum half-life (t1/2) was determined after intravenous (i.v) and subcutaneous (s.c.) bolus injections. The initial t1/2 in serum after i.v. injection was about 10 minutes and the terminal t1/2 close to 2 hours. Subcutaneous administration resulted in plateau levels after 2 to 4 hours, while the apparent terminal t1/2 was similar to that after i.v. infusion. The bioavailability of IL-3 following subcutaneous administration was only about 40% of that following i.v. administration. Hemopoietic effects of continuous i.v. infusion of IL-3 was then compared to s.c. administration in either one, two, or three daily injections. Doses chosen ranged from 1 to 30 micrograms/kg per day. In agreement with the more limited bioavailability of IL-3 following s.c. administration, continuous i.v. infusion was much more effective in stimulating hemopoiesis than s.c. administration. Two or three daily s.c. injections did not improve the hemopoietic response compared to a single s.c. injection, which is in agreement with the apparent terminal t1/2 of 101 min. It is concluded that IL-3 is more effective by continuous i.v. infusion than by subcutaneous administration.

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PubMed1992

Flow cytometric analysis of peripheral blood erythrocyte chimerism in alpha-thalassemic mice.

A rapid and reliable method for longitudinal studies on the degree of red cell chimerism following bone marrow transplantation of alpha-thalassemic recipient mice is presented. Blood obtained by tail clipping from transplanted mice was analyzed by measuring forward light scatter (FLS) distribution of red cells using a flow cytometer. Amplification and threshold of FLS were specifically adjusted. For flow cytometric analysis, the red cells needed to be suspended in hypotonic saline (103 mmol/l NaCl). Osmotic fragility testing showed that lysis of erythrocytes did not significantly influence the measurements. Flow cytometric measurement allowed for a rapid determination of the degree of red cell chimerism.

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PubMed1990

Highly increased production of bone marrow-derived blood cells by administration of homologous interleukin-3 to rhesus monkeys.

Recombinant rhesus monkey interleukin-3 (IL-3) was administered to normal rhesus monkeys in graded doses ranging from 3 to 30 micrograms/kg/d subcutaneously for 30 consecutive days or given as a continuous intravenous infusion at a dose of 30 micrograms/kg/d for 16 days. After a lag phase of about 1 week, a highly increased, dose-dependent production of bone marrow-derived blood cells was observed, preceded by amplification of bone marrow hematopoietic progenitor cells. Simultaneously, peripheral blood progenitor cells rose. The increase included basophilic, eosinophilic and neutrophilic granulocytes, monocytes, and the erythrocyte and platelet lineages. Characteristically, a T-lymphocyte response was absent. It is concluded that IL-3 in vivo stimulates blood cell production from an immature, multipotent progenitor cell.

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PubMed1990

Interleukin-3.

Interleukin-3 (IL-3) is a hemopoietic growth factor involved in the survival, proliferation and differentiation of multipotent hemopoietic cells. In five mammalian species, including man, the gene encoding IL-3 has been isolated and expressed to yield the mature recombinant proteins. The human IL-3 gene encodes a protein of 133 amino acids with two conserved cysteine residues and 2 potential N-linked glycosylation sites; human native IL-3 has not been characterized. Comparison of the IL-3 genes revealed a more rapid evolutionary divergence than has been observed for other hemopoietic growth factors, and, hence, a more pronounced species specificity of the functional proteins was found. In agreement with its stimulatory action on immature multipotent cells, the in vivo actions of homologous recombinant IL-3 in nonhuman primates include a highly increased production of blood cells along the neutrophilic, eosinophilic and basophilic granulocyte as well as the monocyte, red cell and platelet lineages.

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