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R G Andrews

Publications and source records attributed to R G Andrews.

At least 19 recordsLinked to original sources
PubMed1992

The ligand for c-kit, stem cell factor, stimulates the circulation of cells that engraft lethally irradiated baboons.

Recombinant human stem cell factor (SCF), the ligand for c-kit, has been shown to stimulate increased numbers of hematopoietic progenitor cells of multiple types to circulate in the blood of baboons, but it was not known if the cells stimulated to circulate by SCF contained cells capable of engrafting and rescuing lethally irradiated baboons. Peripheral blood mononuclear cells (PBMNC) were collected by leukapheresis from four untreated control baboons and from three baboons on the 10th or 11th day of treatment with SCF (200 micrograms/kg/d). All animals were transplanted with 1.00 to 1.04 x 10(8)/kg of cryopreserved autologous PBMNC after treatment with a single dose of 1,020 cGy total body irradiation (TBI). Three animals were transplanted with PBMNC that had been collected during SCF treatment, 24 to 38 days after the last dose of SCF. Rapid trilineage engraftment was documented by bone marrow biopsy in all three. The mean time to a total white blood cell count (WBC) > or = 500/microL, WBC > or = 1,000/microL, and an absolute neutrophil count (ANC) > or = 500/microL was 15 +/- 3 (mean +/- SD), 19 +/- 1, and 19 +/- 2 days, respectively. Two animals remain alive with stable engraftment more than 180 and 245 days posttransplant. The third died of sepsis 32 days posttransplant with a hypercellular marrow showing trilineage engraftment. The surviving animals were transfusion independent by 10 and 59 days posttransplant. Four control animals were transplanted with PBMNC collected in the absence of SCF stimulation. One was treated for 11 days with SCF (200 micrograms/kg/d) after PBMNC were collected. This animal was transplanted 25 days after the last dose of SCF. None of the four control animals engrafted and they died 13, 16, 28, and 38 days posttransplant with marrow aplasia. Treatment with SCF stimulates the circulation of cells that engraft and rescue lethally irradiated baboons. The characteristics of the transplantable cells present in the circulation are now amenable to direct study.

Animals↗
PubMed1992

CD34+ marrow cells, devoid of T and B lymphocytes, reconstitute stable lymphopoiesis and myelopoiesis in lethally irradiated allogeneic baboons.

CD34+ cells devoid of detectable mature and immature T and B lymphocytes, expressing the CD2, CD10, and CD20 antigens, were isolated from marrows of three pairs of sex-mismatched, mixed lymphocyte culture (MLC) nonreactive, sibling baboons. Reciprocal transplants were performed between members of each pair, using the sex chromosomes, identified by standard cytogenetic techniques, as markers of the transplanted cells. Five animals from these three pairs were transplanted with 0.6 to 2.1 x 10(6)/kg of isolated cryopreserved and/or fresh isolated cells that were greater than 95% to 97% CD34+. Before transplantation, animals were treated with either single (920 or 1,020 cGy) or split (700 cGy x 2) dose total body irradiation. All animals engrafted with donor cells, as demonstrated by cytogenetic analysis of bone marrow metaphase cells 4 weeks after transplantation, with days to white blood cell count (WBC) greater than 500 being 19 +/- 2, to WBC greater than 1,000 23 +/- 2, to absolute neutrophil count greater than 500 24 +/- 3, and to platelets greater than 20,000 30 +/- 7. Three animals died of infectious-related complications at 34, 42, and 109 days after transplantation with evidence of host and donor cells (mixed chimerism) in marrow. Two animals remain alive and healthy more than 545 and 455 days after transplantation with stable mixed chimerism in marrow and blood. For these two animals, cytogenetic analysis of granulocyte/macrophage and erythroid colonies derived from marrow precursors between weeks 25 and 42 posttransplant showed evidence of mixed chimerism. Cytogenetic studies of CD2+ T cells and CD20+ B cells isolated from blood of these two animals between weeks 21 and 51 posttransplant showed the presence of mixed chimerism in both lymphocyte populations. Thus, isolated allogeneic CD34+ marrow cells devoid of detectable mature and immature T and B lymphocytes can engraft and reconstitute stable long-term myelopoiesis and lymphopoiesis in lethally irradiated baboons. These results are consistent with the hypothesis that CD34+ marrow cells contain pluripotent hematopoietic stem cells capable of fully reconstituting lymphohematopoiesis in the transplanted host.

Animals↗
PubMed1992

A c-kit ligand, recombinant human stem cell factor, mediates reversible expansion of multiple CD34+ colony-forming cell types in blood and marrow of baboons.

The ligand for the human c-kit, recombinant human stem cell factor (SCF), was administered to baboons at doses of 200, 100, 50, 25, and 10 micrograms/kg/d. SCF induced a dose-dependent expansion of hematopoietic colony-forming cells (CFC) of multiple types in both blood and marrow, including colony-forming unit (CFU) granulocyte-monocyte, burst-forming unit-erythroid, CFU-MIX, and high proliferative potential-CFC. These changes were associated with a dose-dependent leukocytosis, involving all leukocyte lineages, a reticulocytosis, and increases in marrow cellularity. At 200 micrograms/kg/d of SCF, CFC in blood were increased 10-fold to greater than 100-fold. This correlated with an increased frequency of CD34+ cells in blood. The frequency of CFC in blood approached that of marrow in some animals. These changes were reversed within 7 to 14 days of stopping SCF. The results of these studies suggest a role for the c-kit ligand in stimulating the expansion of multiple CFC types in blood and marrow for potential therapeutic purposes.

Animals↗
PubMed1992

Abnormal responsiveness of granulocyte-committed progenitor cells in cyclic neutropenia.

The mechanism(s) driving cyclic hematopoiesis in human cyclic neutropenia remains unknown. Clinical trials suggest that an abnormal responsiveness of bone marrow progenitor cells to hematopoietic growth factors might cause oscillatory blood counts. Studies were performed to determine whether an abnormal responsiveness to multiple growth factors exists in this disorder and whether the defect could be shown in highly enriched populations of marrow progenitor cells. Bone marrow mononuclear cells from patients with congenital cyclic neutropenia required higher concentrations of added granulocyte-colony-stimulating factor (G-CSF) to achieve half-maximal colony growth than cells from normal subjects (478 +/- 90 pmol/L v 53 +/- 12 pmol/L, P less than .01). Patients also differed in requirement for granulocyte-macrophage-CSF (P less than .05), but not for interleukin-3 (P greater than .30). CD34+ bone marrow cells from three patients also showed this difference in G-CSF responsiveness (P less than .05). These data suggest that the defect in congenital cyclic hematopoiesis lies in growth factor receptor binding or the postreceptor signal transduction system that drives granulocytopoiesis.

Bone Marrow↗
PubMed1992

Differences in the frequency of normal and clonal precursors of colony-forming cells in chronic myelogenous leukemia and acute myelogenous leukemia.

Acute myelogenous leukemia (AML) is a clonal disease that is heterogeneous with respect to the pattern of differentiative expression of the leukemic progenitors. In some patients, the involved stem cells manifest pluripotent differentiative expression, whereas in others, the involved progenitors manifest differentiative expression mainly restricted to the granulocytic pathway. This is in contrast to chronic myelogenous leukemia (CML) which is a clonal disease known to arise in a pluripotent stem cell. Therefore, we tested whether these leukemias could be distinguished with respect to their involvement of immature precursors by studying colony-forming cells (CFC) and their precursors from four glucose-6-phosphate dehydrogenase (G6PD) heterozygous patients with AML and five patients with CML. CFC were separated from their precursors by FACS for expression of CD33 and CD34 followed by growth in a long-term culture (LTC) system. The vast majority of CFC express both the CD33 and CD34 antigens, but their less mature precursors, detected by their ability to give rise to CFC in LTC, express only CD34. In three of the four patients with AML, the CD33-CD34+ cells produced CFC in LTC that appeared to be predominantly or completely normal (ie, nonclonal) in origin. In the fourth patient, a significant enrichment of nonclonal progenitors was obtained in the CD33-CD34+ population, but these cells may also have included significant numbers of clonal cells. In contrast, in four of five patients with CML, cultures of both the CD33-CD34+ and CD33+CD34+ populations produced CFC in LTC that were almost entirely clonal in origin, whereas in the fifth patient a substantial number originated from nonclonal stem cells. These data indicate that granulocyte/monocyte progenitors are predominantly clonally derived in CML and AML. In CML, their precursors are also predominantly clonal, but in some cases of AML they are not. These findings may have implications for understanding the success or failure of current therapies of AML and CML.

Antigens, CD↗
PubMed1991

Recombinant human stem cell factor, a c-kit ligand, stimulates hematopoiesis in primates.

Recombinant human stem cell factor (SCF) is homologous with recombinant rat SCF (rrSCF) and is a ligand for c-kit. We determined the influence of SCF on hematopoiesis in vitro and in vivo in baboons. In vitro, SCF alone stimulated little growth of hematopoietic colony-forming cells from baboon marrow, but did increase the number of colonies formed in response to erythropoietin (Epo), interleukin-3 (IL-3), and granulocyte-macrophage colony-stimulating factor (GM-CSF). In vivo, SCF caused an increase in the peripheral blood of the number of erythrocytes, neutrophils, lymphocytes, monocytes, eosinophils, and basophils. In marrow, it caused an increase in marrow cellularity and in the absolute number of colony-forming unit-granulocyte-monocyte (CFU-GM) and burst-forming unit-erythroid (BFU-E) in marrow following infusion of SCF. The in vivo stimulation of multiple lymphohematopoietic lineages corroborates previous in vitro studies and suggests a potentially important clinical role for SCF.

Animals↗
PubMed1991

Recombinant human stem cell factor enhances the formation of colonies by CD34+ and CD34+lin- cells, and the generation of colony-forming cell progeny from CD34+lin- cells cultured with interleukin-3, granulocyte colony-stimulating factor, or granulocyte-macrophage colony-stimulating factor.

We tested the ability of recombinant human stem cell factor (SCF) to stimulate isolated marrow precursor cells to form colonies in semisolid media and to generate colony-forming cells (CFC) in liquid culture. SCF, in combination with interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), or granulocyte colony-stimulating factor (G-CSF) caused CD34+ cells to form increased numbers of granulocyte-macrophage colonies (CFU-GM), and to form macroscopic erythroid burst-forming units (BFU-E) in the presence of IL-3, erythropoietin (Epo), and SCF. We tested isolated CD34+lin- cells, a minor subset of CD34+ cells that did not display antigens associated with lymphoid or myeloid lineages, and CD34+lin+ cells, which contain the vast majority of CFC, and found that the enhanced colony growth was most dramatic within the CD34+lin- population. CD34+lin- cells cultured in liquid medium containing SCF combined with IL-3, GM-CSF, or G-CSF gave rise to increased numbers of CFC. Maximal numbers of CFU-GM were generated from CD34+lin- cells after 7 to 21 days of culture, and required the presence of SCF from the initiation of liquid culture. The addition of SCF to IL-3 and/or G-CSF in cultures of single CD34+lin- cells resulted in increased numbers of CFC due to the proliferation of otherwise quiescent precursors and an increase in the numbers of CFC generated from individual precursors. These studies demonstrate the potent synergistic interaction between SCF and other hematopoietic growth factors on a highly immature population of CD34+lin- precursor cells.

Antigens, CD↗
PubMed1991

Proliferative responses to interleukin-3 and granulocyte colony-stimulating factor distinguish a minor subpopulation of CD34-positive marrow progenitors that do not express CD33 and a novel antigen, 7B9.

Human hematopoietic colony-forming cells (CFC) express the CD34 antigen (CD34+) as well as differentiation antigens such as CD33 and HLA-DR. CD34+ cells that do not express these latter differentiation antigens have been shown to contain few CFC in direct culture, but generate increasing numbers of CFC when cultured over a marrow stromal cell layer in the long-term culture system. In this study we determined if CD34+ cells with low or absent expression of CD33 and a novel antigen, 7B9 (CD34+CD33-7B9-), could be distinguished from CD34+ cells expressing these antigens (CD34+CD33+7B9+) based on their proliferative responses to interleukin-3 (IL-3) and granulocyte colony-stimulating factor (G-CSF) in a short-term liquid culture system. These two populations were separated by fluorescence-activated cell sorting, cultured with IL-3 (10 ng/mL), G-CSF (100 ng/mL), or IL-3 and G-CSF, and 3H-thymidine uptake was measured. CD34+CD33-7B9- cells proliferated in the presence of IL-3, but not G-CSF. However, a synergistic response to the combination of IL-3 and G-CSF was seen in most experiments. In contrast, CD34+CD33+7B9+ cells proliferated in the presence of either IL-3 or G-CSF but did not display an additive or synergistic response to the combination of IL-3 and G-CSF. In colony-forming assays performed before and after liquid culture, the CD34+CD33-7B9- cells in two experiments contained 0.3% and 2.2% of all sorted marrow CFC before liquid culture and generated 40-fold and ninefold increases in the number of granulocyte-macrophage colony-forming units (CFU-GM), respectively, after liquid culture with IL-3 and G-CSF. In contrast, the CD34+CD33+7B9+ cells contained 99.7% and 97.8% of all sorted marrow CFC before liquid culture and had no change or a threefold increase in the number of CFU-GM, respectively, after liquid culture with IL-3 and G-CSF. Single-cell liquid cultures containing IL-3 and G-CSF with cells that were either CD34+CD33-7B9- and depleted of mature lymphoid cells (CD34+lin-) or were CD34+lin+ showed that a higher proportion of wells containing a CD34+lin- cell gave rise to one or more CFC (8.7%) than did wells containing a CD34+lin+ cell (2.9%), with the responding cells in the former population giving rise to an average of 2.9 +/- 0.6 CFC and in the latter population, 2.0 +/- 1.0 CFC.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗
PubMed1991

Engraftment after infusion of CD34+ marrow cells in patients with breast cancer or neuroblastoma.

The CD34 antigen is expressed by 1% to 4% of human and baboon marrow cells, including virtually all hematopoietic progenitors detectable by in vitro assays. Previous work from our laboratory has shown that CD34+ marrow cells can engraft lethally irradiated baboons. Because the CD34 antigen has not been detected on most solid tumors, positive selection of CD34+ cells may be used to provide marrow cells capable of engraftment, but depleted of tumor cells. In seven patients with stage IV breast cancer and two patients with stage IV neuroblastoma, 2.5 to 17.5 x 10(9) marrow cells were separated by immunoadsorption with the anti-CD34 antibody 12-8 and 50 to 260 x 10(6) positively selected cells were recovered that were 64 +/- 16% (range 35% to 92%) CD34+. The patients received 1.0 to 5.2 x 10(6) CD34-enriched cells/kg after marrow ablative therapy. Six patients engrafted, achieving granulocyte counts of greater than 500/mm3 at 34 +/- 10 (range 21 to 47) days and platelets counts of greater than 20,000/mm3 at 46 +/- 14 (range 28 to 66) days posttransplant. Five of these patients showed durable engraftment until the time of death 82 to 386 days posttransplant. One patient failed to sustain engraftment associated with metastatic marrow disease. Three patients died at days 14, 14, and 17 posttransplant, two of whom had evidence of early engraftment. These studies suggest that CD34+ marrow cells are capable of reconstituting hematopoiesis in humans.

Antigens, CD↗
PubMed1991

Blast colony-forming cells and precursors of colony-forming cells detectable in long-term marrow culture express the same phenotype (CD33- CD34+).

We have previously shown that CD33- CD34+ human marrow cells are capable of giving rise to colony-forming cells (CFC) in long-term marrow culture (LTMC) but are mainly depleted of progenitors that directly form colonies in semi-solid media. In contrast, the CD33+ CD34+ population contains most of the CFC but not the precursors of these cells detectable in LTMC. The purpose of the present study was to determine if a form of CFC with self-renewal potential, the blast CFC, is contained within the CD33+ CD34+ or CD33- CD34+ population. The results demonstrate that blast CFC segregate within the CD33- population, representing a distinct progenitor population that may be analogous to progenitors for CFC detectable in LTMC.

Antigens, CD↗
PubMed1990

Human hematopoietic precursors in long-term culture: single CD34+ cells that lack detectable T cell, B cell, and myeloid cell antigens produce multiple colony-forming cells when cultured with marrow stromal cells.

CD34+ human marrow cells not expressing T cell-, B cell-, and myeloid cell-associated antigens (TBM-) were cloned by two-color cell sorting into culture wells containing irradiated marrow stromal cells. After 4 wk of culture, 3.7 +/- 2.1% of these cells generated colony-forming cells (CFC), with each of these cells generating 6.3 +/- 5.3 CFC. This was not due to the 0.5 +/- 0.5% CFC present in the purified CD34+ TBM- cells, as less than 1% of CFC persist in these cultures. This is the first demonstration that single immature precursor cells in human long-term cultures generate multiple CFC progeny. The immature nature of these clonable CD34+ TBM- precursors suggests their candidate status as human hematopoietic stem cells.

Antibodies, Monoclonal↗
PubMed1990

Stem cell selection--clinical experience.

The ability to isolate large numbers of hematopoietic progenitors will facilitate an understanding of the growth and differentiation of bone marrow. Furthermore, isolating hematopoietic progenitors will have widespread clinical applications to autologous marrow transplantation, allogeneic marrow transplantation, gene therapy, and in vitro marrow expansion. With the development of avidin-biotin immunoadsorption, it is now feasible to isolate large numbers of these progenitor cells for clinical purposes. Successful hematopoietic reconstitution has been demonstrated in lethally irradiated baboons transplanted with CD34+ cells isolated by immunoadsorption with the anti-CD34 antibody 12-8. Recent studies have shown that CD34+ cells enriched from the marrow of patients with metastatic breast cancer can be used for autologous marrow transplantation.

Animals↗
PubMed1990

Positive selection of hematopoietic progenitors from marrow and peripheral blood for transplantation.

The ability to obtain large numbers of purified hematopoietic progenitors (HPC) will facilitate the understanding of elements that influence the growth and differentiation of bone marrow. Furthermore, HPC isolation will have direct application to autologous marrow transplantation (AMT) for malignancies as well as facilitate the transfer of genes in marrow cells for the correction of genetic disorders. The transplantation of HPC will help delineate the cells or factors responsible for graft rejection and graft-versus-host-disease. Or several techniques that have been utilized for the separation of HPC, only the avidin-biotin immunoadsorption (ABIA) method has been shown capable of separating the number of cells required for large animals and man. The application of this technique to AMT in man requires the identification of an antigen found predominantly on HPC in peripheral blood or marrow but not on malignant cells that could potentially contaminate bone marrow. Studies have demonstrated that the CD34 antigen is expressed by the majority of human marrow HPC measured in long-term marrow culture and is expressed on cells capable of autologous engraftment in lethally irradiated baboons. Although the CD34 antigen is not detectable by FACS analysis on peripheral blood cells, ABIA can enrich for such cells. The CD34 antigen is not detected on cells from patients with breast cancer or neuroblastoma thus allowing clinical studies to proceed. Preliminary results suggest that CD34(+)-enriched cells are depleted of tumor cells and are capable of autologous reconstitution in man.

Antigens, CD↗
PubMed1989

Precursors of colony-forming cells in humans can be distinguished from colony-forming cells by expression of the CD33 and CD34 antigens and light scatter properties.

We determined whether human marrow cells that directly form colonies in vitro could be distinguished from cells that generate or become CFC only after LTMC in the presence of irradiated marrow stromal cells. In previous studies, an anti-CD33 antibody, L4F3, and complement (C') were used to lyse nearly all CFC in marrow, and the remaining cells generated CFC in LTMC. In the present studies, marrow cells were treated with L4F3 + C' and the remaining CD33- cells were separated into CD34+ and CD34- populations and placed in LTMC. Only the CD34+ cells were found to generate significant numbers of CFC. To compare the CD33-CD34+ and CD33+CD34+ cells, we isolated each cell population using two-color FACS. Only LTMCs of the CD33-CD34+ cells generated CFC for greater than 5 wk. In contrast, cells that expressed both the CD33 and CD34 antigens, which contained most of the CFC, generated few CFC in LTMC. Fractionation of marrow cells based on right angle and forward light scattering suggested that precursors for CFC have low right angle and low forward light scattering properties. The CD33-CD34+ marrow cells were therefore further fractionated based on light scatter characteristics. Cells with low right angle and low forward light scatter formed few or no colonies on direct culture, yet generated greater numbers of CFC after 4 wk of LTMC than did cells with low right angle and high forward light scatter. Most (87-98%) CFC generated in the LTMCs that were initiated with CD33-CD34+ cells were found to express the CD33 antigen. Thus, hematopoietic progenitors with differing proliferative and differentiative potentials can be directly separated on the basis of their expression of CD33 and CD34 cell surface antigens and their light scatter properties.

Antibodies, Monoclonal↗
PubMed1989

Cutaneous and extracutaneous neutrophilic infiltrates (Sweet syndrome) in three patients with Fanconi anemia.

Three patients with coexistent Fanconi syndrome and Sweet syndrome (neutrophilic dermatosis) are presented. These sterile skin lesions responded to systemic corticosteroid therapy in all three cases, and recurred when treatment was discontinued. The association in children of Sweet syndrome with malignancy has previously been recognized; it has not been reported in the premalignant phase of Fanconi anemia. This report expands the differential diagnosis of the neutrophilic dermatoses. Children with Sweet syndrome and anemia should be examined for Fanconi anemia by diepoxybutane cytogenetic studies.

Adult↗
PubMed1989

Interleukin-3, GM-CSF, and G-CSF receptor expression on cell lines and primary leukemia cells: receptor heterogeneity and relationship to growth factor responsiveness.

Recombinant human granulocyte-macrophage (GM) colony-stimulating factor (GM-CSF), G-CSF, and interleukin-3 (IL-3) labeled with 125I were used to study the characteristics and distribution of receptors for these factors on in vitro cell lines and on cells from patients with acute nonlymphocytic leukemia (ANL) and acute lymphocytic leukemia (ALL). Receptors for GM-CSF and G-CSF were restricted to a subset of myelomonocytic cell lines whereas IL-3 receptors were also found on pre-B- or early B-cell lines. Receptors for all three CSFs were broadly distributed on ANL cells, with considerable variability in levels of expression. Measurement of the colony-forming ability of ANL cells in response to the CSFs showed that there was no direct correlation between the ability of the cells to respond to a growth factor and the absolute number of receptors expressed for that growth factor. Binding of radiolabeled IL-3 and GM-CSF to ANL cells produced complex biphasic curves. Further analysis showed that both IL-3 and GM-CSF were able to partially compete for specific binding of the heterologous radiolabeled ligand to cells from several ANL patients, suggesting that heterogeneity may exist in human CSF receptors. These results provide new insights into the complex role that CSFs may play in ANL.

Cell Division↗
PubMed1988

Endotoxin-associated protein: a potent stimulus for human granulocytopoietic activity which may be accessory cell independent.

Proteins coextracted with endotoxin, termed endotoxin-associated protein (EAP), have been shown to exert interleukin 1-like activities. The present studies demonstrate that EAP also exerts potent granulopoietic colony-stimulating activity (CSA) on human peripheral blood and bone marrow progenitor cells, comparable to that seen with various types of conditioned media. The CSA observed with EAP appeared to be heat (100 degrees C, 30 min) and trypsin resistant and partially pronase resistant. Similar resistance was observed with the porin proteins of the outer membrane of gram-negative bacteria, and similar CSA activity was observed with a purified porin preparation of Neisseria gonorrhoeae. The CSA of EAP could be demonstrated in human peripheral blood and bone marrow leukocytes rigorously depleted of monocytes, T lymphocytes, and B lymphocytes by treatment with specific monoclonal antibodies and complement.

Antigen-Presenting Cells↗