Showing papers on "Haematopoiesis published in 1979"

Properties of haematopoietic stem cells surviving 5-fluorouracil treatment: evidence for a pre-CFU-S cell?

Abstract: The spleen colony assay of Till and McCulloch1, which is a clonal assay2, is considered to be a measure of the stem cell content of haematopoietic tissue. Stem cells are a heterogeneous population3–6 with respect to their capacity to generate further stem cells (assayed as colony-forming units in spleen, CFU-S) and progenitors of red cells, granulocytes, macrophages and platelets. It has been suggested that stem cells are organised for use according to their generation age5,6. There is evidence to indicate that drugs such as hydroxyurea (HU) and 5-fluorouracil (5-FU), which preferentially eliminate proliferating cells, spare non-cycling stem cells which have a high capacity to generate other stem cells6 and progenitors of granulocytes and macrophages6 as well as megakaryocytes7. We show here, however, that the CFU-S content of haematopoietic tissue is not an adequate predictor of the capacity of that tissue to repopulate bone marrow of a lethally irradiated host. Furthermore it appears that haematopoietic stem cells are not only heterogeneous with respect to their capacity to generate other stem cells and progenitors of haemic cells in the spleen but also differ in their capacity to ‘home’ to either the bone marrow or spleen. The evidence suggests a class of ‘primitive’ haematopoietic stem cell (pre-CFU-S) that accumulates in the bone marrow to give rise to cells capable of growing in spleen.

Three new types of viral oncogene of cellular origin specific for haematopoietic cell transformation

Abstract: The RNAs of seven replication-defective leukaemia virus (DLV) strains contain three types of unique sequences, which correlate with the capacity of a given virus strain to transform erythroblasts, macrophage-like cells and myeloblasts, respectively. These sequences, termed erb, mac and myb, have their counterparts in the normal DNA of avian and mammalian species. Our results indicate that DLVs represent recombinants between a common 'vector' related to a chicken endogenous virus and one of three types of cellular gene possibly involved in haematopoietic differentiation.

Do natural killer cells engage in regulated reactions against self to ensure homeostasis

Abstract: Host reactivities not requiring immunization in the mouse, especially natural resistance of irradiated animals to accept grafts of normal or malignant hemopoietic cells, were compared with NK activity against the YAC-1 lymphoma. The effects of several independent variables known to influence natural resistance in vivo had a similar effect on the NK system. Figure 12 lists an impressive array of shared properties and positive correlations. In contrast, the distinctions were few and minor. Many of the positive correlations were of particular significance since the experimental variables either have opposing or no effects on conventional induced immunity. The multiplicity and pervasiveness of these correlations suggest that the cellular mechanisms underlying natural reactivities are similar or common. Cytotoxic effectors mediating natural resistance to normal cells, tumors, and cells infected with intracellular pathogens may be distinct in terms of target selectivity, yet belong to a single cell lineage subject to common regulatory influences for differentiation and function. Regulation of reactivity via suppressor cells was studied in the NK system only. The spleens of mice selected for low levels of NK activity (resulting from young age, irradiation, and treatment with the macrophage-active agents l-carrageenan or hydrocortisone acetate) contained cells capable of inhibiting the lytic function of NK effectors taken from untreated adult donors. All the suppressor cells studied were thymus-independent, as judged by their occurrence in spleens of genetically athymic mice; the suppressive function was resistant to 2000 rads of gamma-rays administered in vitro and was not restricted by the major histocompatibility complex, without exception. However, two major classes of suppressors were identified: (a) macrophagelike cells inducible by l-carrageenan or hydrocortisone acetate, and (b) nonadherent cells found in spleens of untreated infants and of irradiated adult mice. It is proposed that the suppression of NK cytolysis demonstrated in vitro was a manifestation of regulatory mechanisms modulating the level of NK activity in vivo. Macrophagelike cells that are induced, activated, or inactivated by bacteria, viruses, hormones, and other agents may act as regulators of differentiation, maturation, and function of cells belonging to the NK lineage. Nonadherent cells could be either a distinct class of suppressors or immature NK cells capable of binding but not lysing target cells. In the latter case, regulation would be achieved via competitive binding of targets by pre-NK cells presumably in dynamic equilibrium with functional (i.e. matured) NK effectors.

Regulation of macrophage and granulocyte proliferation. Specificities of prostaglandin E and lactoferrin

Abstract: Hemopoietic colony-forming cells committed to macrophage differentiation (M-CFC) are selectively and differentially inhibited by prostaglandin E (PGE). A hierarchy of sensitivity was observed among murine CFC stimulated by colony-stimulating factors (CSF) which differ in their ability to initiate proliferation of morphologically distinct colony types, or stimulated by CSF provided by macrophage feeder layers. Inhibition of macrophage colony formation to 50 percent levels occurred with PGE concentrations between 10(-8) and 10(-9) M, and was still evident at 10(-10) -10(-11) M PGE concentrations. The growth of mixed colonies containing both macrophages and neutrophils was less sensitive to the inhibitory effects of PGE, however, the monocytoid component of these colonies was reduced in the presence of PGE. Neutrophil progenitor cell proliferation was not influenced by PGE concentrations below 10(-6) M, regardless of time of addition of PGE, whereas clonal macrophage expansion, as well as clone size, was sensitive to inhibition by PGE when added as late as 3 d after culture initiation. Prostaglandin F(2α), was not inhibitory to colony formation. Experimental evidence for a selective role of macrophage PGE in the regulation of macrophage colony formation was directly provided by utilizing resident peritoneal macrophages as a source of CSF for bone marrow target cell overlays. Simultaneous morphological analysis of colonies proliferating in bilayer culture in response to increasing concentrations of macrophages, and direct measurements of PGE synthesized by an identical number of macrophages maintained in liquid culture demonstrate that a specific decline in macrophage colony formation occurs coincident with a linear increase in macrophage PGE synthesis. Inhibition of macrophage PGE synthesis by indomethacin results in the specific enhancement of macrophage colony formation. Furthermore, macrophage PGE synthesis is induced by CSF preparations with the selective capacity to differentially stimulate macrophage proliferation, but not by those which preferentially stimulate granulocyte colony formation. In comparison to the effects of PGE on M-CFC, polymorphonuclear granulocyte-derived lactoferrin (LF) reduces macrophage production of colony-stimulating activities for macrophage, mixed macrophage- neutrophil and neutrophil colony formation. The ability of LF to reduce macrophage PGE synthesis, presumably by decreasing CSF production, suggests that LF and PGE can interact in the control of macrophage and granulocyte proliferation.

Hematopoietic Stem Cells

Abstract: (First of Three Parts) IN man, most tissues consist primarily of differentiated cells that normally show little evidence of proliferation and self-renewal. However, the gastrointestinal mucosal cel...

Organization of haemopoietic stem cells: the generation-age hypothesis.

Abstract: This paper proposes that the previous division history of each stem cell is one determinant of the functional organization of the haemopoietic stem cell population. Stem cells from a lineage of stem cells which have generated many stem cells (older stem cells) are used in the animal to form blood before stem cells which have generated few stem cells (younger stem cells). The stem cell generating capacity of a lineage of stem cells is finite. After a given number of generations a stem cell is lost to the stem cell compartment by forming two committed precursors of the cell lines. Its part in blood formation is taken by the next oldest stem cell. We have called this proposal the generation-age hypothesis. Experimental evidence in support of the proposal is presented. We stripped away older stem cells from normal bone marrow and 13 day foetal liver with phase-specific drugs and revealed a younger population of stem cells whose capacity for stem cell generation was three- to four-fold greater than that of the average normal, untreated population. We aged normal stem cells by continuous irradiation and serial retransplantation and found that their stem cell generative capacity had declined eight-fold. We measured the stem cell generative capacity of stem cells in the bloodstream. It was a half to a quarter that of normal bone marrow stem cells and we found a subpopulation of circulating stem cells whose capacity for stem cell generation was an eighth to a fortieth that of normal femoral stem cells. This subpopulation was identified by its failure to express the brain-associated antigen which was present on 75% of normal femoral stem cells but was not found on their progeny, the committed precursors of granulocytes.

Cellular interactions in haematopoiesis.

Abstract: In vitro culture of haematopoietic cells has provided some surprising insights into critical interactions of blood-forming cells. Subpopulations of lymphoid cells have been shown to produce colony-stimulating activity, to interact with macrophages, and to have important effects on the very early stages of erythropoiesis. Macrophages have multiple influences on the proliferation and differentiation of other haematopoietic cells.

The Hematopoietic System

Abstract: Anemia is probably the commonest effect of nutritional deficiency in human beings and has certainly been the most extensively studied. Iron deficiency is widely recognized as the most important cause of anemia in the world (Finch, 1969; Beaton, 1974).

Prevention of genetic anemias in mice by microinjection of normal hematopoietic stem cells into the fetal placenta

Abstract: Mice homozygous for mutant genes at the W locus have a marked macrocytic anemia that is fatal in some genotypes. The defect is believed to originate in the developmentally pluripotent hematopoietic stem cell population. Anemia is first grossly manifest on day 13 of gestation, when the liver is the chief hematopoietic organ. The known paucity of blood-forming foci in livers of homozygotes and the limited formation of their erythrocytes suggested that such fetuses—unlike normal ones—might have conditions favorable for in utero seeding of genetically normal hematopoietic tissue. If this were accomplished before day 13, the anemia might essentially be prevented, or at least substantially mitigated, and normalcy soon achieved by cell selection. This proved to be the case. Allogeneic normal fetal liver cells were microinjected into the blood vessels of the fetal placenta on day 11 of gestation. Of eight mutant homozygotes born from segregating matings, six (four W/W, two Wv/Wv) were successfully populated with donor cells. Strain-specific hemoglobin markers demonstrated replacement of the erythroid lineage with the normal type, the rate of substitution being more rapid in the W/W (ordinarily more anemic) recipients. Strain-specific isozyme differences revealed that white blood cells were also replaced. Thus, the initial selective pressure, hence the W-mutant phenotypic lesion, must have occurred at the pluripotent stem cell stage. The animals remained immunologically tolerant of the donor cells and no graft-versus-host reaction occurred. The early introduction of hematopoietic cells differing genetically from all the other tissues of the animal provides possibilities for tracing normal hematopoietic lineages in vivo, for analyzing cell and tissue interactions, such as those between lymphocytes and thymus, and for clarifying the etiology of other blood or immune insufficiencies or malignancies.

Colony formation in agar by multipotential hemopoietic cells.

Abstract: Agar cultures of CBA fetal liver, peripheral blood, yolk sac and adult marrow cells were stimulated by pokeweed mitogen-stimulated spleen conditioned medium. Two to ten percent of the colonies developing were mixed colonies, documented by light or electron microscopy to contain erythroid, neutrophil, macrophage, eosinophil and megakaryocytic cells. No lymphoid cells were detected. Mean size for 7-day mixed colonies was 1,800-7,300 cells. When 7-day mixed colonies were recloned in agar, low levels of colony-forming cells were detected in 10% of the colonies but most daughter colonies formed were small neutrophil and/or macrophage colonies. Injection of pooled 7-day mixed colony cells to irradiated CBA mice produced low numbers of spleen colonies, mainly erythroid in composition. Karyotypic analysis using the T6T6 marker chromosome showed that some of these colonies were of donor origin. With an assumed f factor of 0.2, the mean content of spleen colony-forming cells per 7-day mixed colony was calculated to vary from 0.09 to 0.76 according to the type of mixed colony assayed. The fetal and adult multipotential hemopoietic cells forming mixed colonies in agar may be hemopoietic stem cells perhaps of a special or fetal type.

Ontogeny of terminal deoxynucleotidyl transferase-positive cells in lymphohemopoietic tissues of rat and mouse.

Abstract: The ontogeny of hemopoietic cells which contain the enzyme terminal deoxynucleotidyl transferase (TdT) was studied in rats and mice During fetal life, TdT-positive cells were first detected in the thymus, where they appeared on or about day 17 of gestation TdT-positive cells were not found in fetal liver, spleen, or bone marrow, but appeared in bone marrow and spleen on the day after birth In the rat, peak levels of TdT-positive cells were attained at 3 to 4 weeks of age in thymus, bone marrow, and spleen, accounting for 67, 39, and 23% of nucleated cells, respectively The percentages of TdT-positive cells in thymus and bone marrow decreased gradually thereafter, whereas, TdT-positive cells in spleen were no longer detectable by 7 weeks of age Normal percentages of TdT-positive cells were found in bone marrow and spleen from neonatally thymectomized rats and congenitally athymic (nu/nu) mice Dexamethasone treatment resulted in a marked decrease in TdT-positive cells The results are discussed with respect to the putative role of TdT-positive hemopoietic cells as thymocyte progenitors

Isolation and characterisation of a bipotential haematopoietic cell line.

Abstract: VARIOUS cell lines have been used to study the regulation of proliferation and differentiation, and events occurring during mutagenesis and carcinogenesis. These include ‘normal’ cell lines which, however, frequently show chromosome changes, especially aneuploidy, and where normality is based essentially on the nontumorigenic capacity of the cells. Whether such cells retain the ability to fulfil their genetically programmed functional state in vivo has not been determined. Moreover, although studies using transformed, tumorigenic cells (Friend leukaemia1, myeloid leukaemia2 and neuroblastoma3) have given useful information on some of the factors involved in differentiation, the fact that the cells are tumorigenic indicates that caution must be exercised in the interpretation of results. We report that we have now isolated and cloned an autonomous haematopoietic cell line where the cells have a diploid complement of chromosomes, are non-tumorigenic and bipotential (can be induced to differentiate in vivo into two distinct haematopoietic lineages), and which in appropriate circumstances protect mice from potentially lethal radiation.

Haemopoiesis in long-term bone marrow cultures. A review.

Abstract: Bone marrow-derived adherent cell layers, containing endothelial cells, fat cells and macrophages will support prolonged haemopoiesis invitro. Evidence suggests that the adherent layer is acting as an invitro haemopoietic inductive environment for stem cell proliferation and differentiation into the variety of committed progenitor cells of the granulocytic, erythroid, megakaryocytic and lymphoid lineages. Using this system we have analysed the factors controlling proliferation of stem cells (CFU-S), differentiation and maturation of granulocyte/macrophage precursor cells (CFU-C), leukaemic transformation by chemicals and viruses, the role of environment versus stem cells in the aetiology of haemopoietic aplasias and the possible usefulness of long-term cultures for bone marrow transplantation.

Antibody-Mediated Aplastic Anemia and Diffuse Fasciitis

Abstract: IT has been suggested that aplastic anemia may be due to either a deficiency of hematopoietic stem cells or an adverse interaction between stem cells and factors in the marrow microenvironment.1 Th...

Abelson virus-transformed haematopoietic cell lines with pre-B-cell characteristics.

Abstract: THE Abelson murine leukaemia virus (A-MuLV) complex, which consists of a replication-defective focus-forming virus and its helper Moloney leukaemia virus, causes a thymus-independent lymphosarcoma in BALB/c mice1. Infection in vivo leads to the production of tumours which are usually classified as ‘null’ lymphoid cells2, although immunoglobulin (Ig)-synthesising B-cell lines have been reported3–5 and macrophage lines may occasionally be produced6. In some cases, particularly with pretreatment of the mice with the mineral oil pristane, there is a high incidence of Ig-producing plasmacytomas7. Additional data on Ly phenotypes have suggested that most A-MuLV tumours, including those with no demonstrable Ig synthesis, may be B-cell lineage derivatives8. Here, we provide evidence for A-MuLV transformation of B-cell precursors resulting in two cell lines which retain the capacity for inducible IgM synthesis. Line ABC-1 was derived from BALB/c mouse bone marrow cells transformed in vitro by the Abelson virus9 and line ATV-3 from a tumour in a BALB/c mouse inoculated with A-MuLV.

Erythropoietin-stimulated erythropoiesis in long-term bone marrow culture

Abstract: The proliferation of multipotential haematopoietic stem cells (CFU-S) is possible in some long-term bone marrow cultures1–3. Granulocyte and macrophage progenitors (CFU-C)2 and megakaryocyte precursor cells (CFU-M)4 are present in these cultures and undergo full development into mature cells5–7. In contrast, while immature erythroid progenitors (‘early’ BFU-E) are maintained in long-term culture, none of the more differentiated progeny (CFU-E) have been detected, and no morphologically recognisable erythroid cells have been observed8–11. We now describe a modified culture system in which the ‘early’ BFU-E develop into ‘late’ BFU-E in response to added erythropoietin. Further maturation of these cells into CFU-E and non-nucleated erythrocytes can be achieved by mechanical agitation of the long-term cultures or by transferring the cells into dishes which do not allow cell attachment to occur.

Selective effects of cyclosporin A on colony-forming lymphoid and myeloid cells in man.

Abstract: THE properties of the fungus metabolite, cyclosporin A, have suggested its potential as a clinically valuable immunosup-pressive agent(1,2). Experiments in animals have demonstrated that its suppressive action against cell-mediated and humoral immunity is not accompanied by any appreciable myelotoxicity(3,4). In this respect, cyclosporin A contrasts with other immunosuppressants in current use, such as antilymphocyte globulin and azathioprine. There are, however, few data to substantiate a selective toxicity of cyclosporin A against human lymphocytes. Here, we have compared its effects against human lymphoid and myeloid cells, using colony formation by the different cell types as the end point. We found that the compound exhibited far greater toxicity towards a sub-population of T cells than towards either B lymphocytes or haematopoietic precursor cells.

Pluripotential stem cell replication in continuous human, prosimian, and murine bone marrow culture.

Abstract: Prolonged replication of pluripotential stem cells and committed progenitor cells is sustained for prolonged periods in a murine marrow culture system. Alterations in stem cell replication and differentiation are observed after infection of the cultures with Friend virus and Kirsten sarcoma virus consistent with transformation of pluripotential stem cells in the first case and transformation of the macrophage component of the hemopoietic microenvironment in the second. Prolonged myelopoiesis and CFU-c proliferation was also observed in continuous human and prosimian marrow cultures, suggesting the applicability of this technique for analysis of stem cell control and in vitro leukemogenesis in species other than the mouse.