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W J Murphy

Publications and source records attributed to W J Murphy.

At least 145 records · Page 8Linked to original sources
PubMed1992

Growth hormone exerts hematopoietic growth-promoting effects in vivo and partially counteracts the myelosuppressive effects of azidothymidine.

Recombinant human growth hormone (rhGH) was administered to mice to determine its effect on hematopoiesis. BALB/c mice and mice with severe combined immune deficiency (SCID), which lack T cells and B cells, were administered intraperitoneal injections of rhGH for 7 days. Upon analysis, both strains of mice exhibited an increase in splenic and bone marrow hematopoietic progenitor cell content and cellularity, indicating that rhGH can act as a hematopoietic growth factor. C57BL/6 mice were then placed on azidothymidine (AZT). AZT is a reverse transcriptase inhibitor currently used as a treatment for acquired immune deficiency syndrome (AIDS), but which also produces significant myelotoxic effects. Treatment of mice with rhGH partially counteracted the myelosuppressive properties of AZT. Bone marrow cellularity, hematocrit values, white blood cell counts, and splenic hematopoietic progenitor cell content were all significantly increased if rhGH (20 micrograms injected intraperitoneally every other day) was concurrently administered with AZT. Administration of ovine GH (ovGH), which, unlike rhGH, has no effect on murine prolactin receptors, also prevented the erythroid-suppressive effects of AZT in mice, but had no significant effect on granulocyte counts. Thus, the effects of GH are mediated at least in part through GH receptors in vivo. Additionally, when mice were initially myelosuppressed by several weeks of AZT treatment, the subsequent administration of ovGH resulted in an increase in splenic hematopoietic progenitor cells. No significant pathologic effects were observed in mice receiving either repeated rhGH or ovGH injections. Thus, GH exerts significant direct hematopoietic growth-promoting effects in vivo and may be of potential clinical use to promote hematopoiesis in the face of myelotoxic therapy.

Animals↗
PubMed1992

Hematopoietic growth-promoting effects of natural killer cells in mice in response to in vivo administration of human interleukin-2.

BACKGROUND: Interleukin-2 (IL-2) is currently being evaluated as an anti-neoplastic agent because of its stimulatory effects on the immune system. However, little is known about the effects of systemic IL-2 administration on hematopoietic parameters. PURPOSE: Recombinant human IL-2 (rHuIL-2) was administered to mice to evaluate its in vivo hematopoietic effects. The mechanism underlying the effects of rHuIL-2 administration was also determined. METHODS: Mice were given 5 x 10(4) IU of rHuIL-2 for 5 days, and their hematopoietic progenitor cell status was determined as measured by growth in soft agar. Antiserum to natural killer (NK) cell-specific markers was used to ascertain if NK cells were responsible for the hematopoietic effects of rHuIL-2. NK cells were purified and cultured in vitro with rHuIL-2 and then adoptively transferred into syngeneic mice to determine the effects on hematopoiesis. RESULTS: Treatment of mice with rHuIL-2 resulted in a significant increase in bone marrow and splenic hematopoietic progenitor cell content. Mice with severe combined immune deficiency (SCID), which lack T cells and B cells yet have NK cells, also responded to the myelostimulatory effects of rHuIL-2. However, removal of NK cells from the SCID mice with antiserum to NK cell-specific markers abrogated the myelostimulatory properties of rHuIL-2. Adoptive transfer of NK cells that were propagated in vitro with rHuIL-2 into mice also resulted in an increase in splenic hematopoietic progenitor cells. CONCLUSIONS: rHuIL-2 exerts significant myelostimulatory effects after in vivo administration, and NK cells are responsible for at least some of these effects. IMPLICATIONS: These results suggest that NK cells and rHuIL-2 may be of use clinically to promote hematopoiesis after bone marrow transplantation or in the face of other myelotoxic therapy in the treatment of cancer.

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PubMed1992

Interleukin-2-activated natural killer cells can support hematopoiesis in vitro and promote marrow engraftment in vivo.

Purified natural killer (NK) cells were obtained from mice with severe combined immune deficiency (SCID) to ascertain their effect on hematopoiesis. When activated and propagated with recombinant human interleukin-2 (rhIL-2) in vitro, SCID spleen cells maintained a phenotypic and lytic spectrum consistent with a pure population of activated NK cells. When added with syngeneic bone marrow cells (BMC) in soft agar, the activated NK cells could support hematopoietic growth in vitro without the addition of exogenous hematopoietic growth factors. However, when syngeneic BMC were added along with cytokines to produce optimal growth conditions, the addition of NK cells was then inhibitory for hematopoietic colony formation. Antibodies to interferon-gamma (IFN-gamma) partially reversed the inhibitory effects. Supernatants from the NK-cell cultures could also exert these effects on hematopoiesis, although to a lesser extent. Analysis of the NK cell RNA demonstrated that activated NK cells express genes for hematopoietic growth factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte CSF (G-CSF), and IL-1 beta. The NK cells were also found to express IFN-gamma, transforming growth factor-beta 1 (TGF-beta 1), and tumor necrosis factor-alpha (TNF-alpha) mRNA. Analysis of the NK-cell supernatants using factor-dependent myeloid progenitor cell lines showed that the NK cells were producing G-CSF and growth-promoting activity that could not be attributed to IL-1, IL-3, IL-4, IL-5, IL-6, GM-CSF, G-CSF, macrophage CSF (M-CSF), or stem cell factor. The transfer of activated NK cells with BMC into lethally irradiated syngeneic mice resulted in greater BMC engraftment in the recipients. Thus, these results using a pure population of activated NK cells indicate that when activated, these cells can produce a variety of growth factors for hematopoiesis and exert significant hematopoietic growth-promoting effects in vivo.

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PubMed1992

Immunologic and hematologic effects of neuroendocrine hormones. Studies on DW/J dwarf mice.

DW/J dwarf mice lack acidophilic anterior pituitary cells and are deficient in growth hormone and other neuroendocrine mediators. These mice were examined to determine the effects of these deficiencies on hematopoietic and immune system development. Previous studies have suggested that these mice had immunologic defects primarily involving T cell development. However, we have found that these mice exhibit decreased peripheral blood cell counts affecting all lineages (erythrocytic, leukocytic, and platelets). Examination of lymphoid tissues of dwarf mice indicated that their spleens were hypoplastic. Treatment of these mice with recombinant human growth hormone resulted in a significant improvement of peripheral blood counts and spleen cell number. Analysis of the bone marrow indicated a profound deficiency of B cell progenitors in the dwarf mice. However, in untreated dwarf mice, mature B cells and T cells were observed in the spleens. Although treatment with recombinant human growth hormone could correct the hematopoietic deficiencies in these mice, it did not restore the B cell progenitor populations, suggesting that an absence of growth hormone is not solely responsible for this deficiency. Thus, these mice display significant myeloid and lymphoid deficiencies that have been previously undetected.

Animals↗
PubMed1992

Human growth hormone promotes engraftment of murine or human T cells in severe combined immunodeficient mice.

Growth hormone (GH) has previously been implicated in T-cell development, and here we test its efficacy in promoting T-lymphocyte engraftment in mice with severe combined immune deficiency (SCID). SCID mice receiving syngeneic thymocytes and treated with recombinant human GH (rhGH) had significantly better T-cell engraftment in their lymph nodes. Human T-cell engraftment was also strongly promoted by rhGH in SCID recipients receiving human peripheral blood lymphocytes. Additionally, although mature human cells have not been thought to enter the murine thymus, human T cells were detected in the SCID thymus after rhGH treatment. Thus, rhGH can be used to optimize long-term peripheral T-cell engraftment in these human-mouse chimeras and may also be useful clinically in treating T-cell deficiencies.

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PubMed1992

Donor-type activated natural killer cells promote marrow engraftment and B cell development during allogeneic bone marrow transplantation.

Purified NK cells were obtained from mice with severe combined immune deficiency and were activated with human IL-2 (hrIL-2) in vitro to determine if, once activated, these cells could be transferred with compatible bone marrow cells (BMC) and promote marrow engraftment in irradiated allogeneic recipients. After culture with hrIL-2, these cells maintained a phenotypic and lytic spectrum consistent with a pure population of activated NK cells. These activated NK cells were then adoptively transferred with the donor BMC and rhIL-2 into lethally irradiated allogeneic hosts. The addition of NK cells with the BMC allowed for more rapid hematopoietic engraftment as determined through short term studies, and greater donor-derived chimerism with accelerated reconstitution of the B cell population as determined with long term analysis. No evidence of graft-vs-host disease was detected in the recipients receiving the activated NK cells with allogeneic T cell replete BMC and hrIL-2. The mechanism by which the transferred NK cells improved BMC engraftment was at least partly through the abrogation of the host effector cell's ability to mediate resistance to the marrow graft. Thus, the administration of donor-type activated NK cells with BMC and hrIL-2 may significantly augment hematopoietic engraftment and immune reconstitution in the clinical setting of allogeneic BMT without giving rise to graft-vs-host disease.

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PubMed1992

Human-mouse lymphoid chimeras: host-vs.-graft and graft-vs.-host reactions.

Human peripheral blood lymphocytes (huPBL) were injected into mice with severe combined immune deficiency (SCID). It was ascertained that murine natural killer (NK) cells were capable of affecting engraftment of human lymphocytes in SCID mice. The presence of host NK cells resulted in the clearance of the human lymphocytes. Human T lymphocytes were the primary cell to engraft in the SCID recipients, with human T cells being detected in the spleen, lymph nodes, bone marrow and peritoneal cavity of the mice up to several months after transfer. No human T cells were detected in the murine thymus and the level of engraftment in the periphery could be highly variable. Additionally, there appeared to be significant reactions between the human lymphocytes and the murine host resulting in a xenogeneic graft-vs.-host reaction (XGVHR). The predominant manifestation involved splenomegaly resulting from an expansion of murine hematopoietic cells in the spleens of these xenogeneic chimeras. The severity of the XGVHR could be correlated with the extent of human T cell engraftment and the recovered human T cells were found to be in a proliferative state. Thus, there appear to be significant host-vs.-graft and graft-vs.-host interactions occurring in human/mouse lymphocyte chimeras.

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PubMed1992

Recombinant human growth hormone promotes human lymphocyte engraftment in immunodeficient mice and results in an increased incidence of human Epstein Barr virus-induced B-cell lymphoma.

Recombinant human growth hormone (rhGH) previously has been demonstrated to promote human or mouse T-cell engraftment in immunodeficient mice. We then wanted to examine long-term effects of rhGH on human cell engraftment in these mice. Mice with severe combined immune deficiency (SCID) were given human peripheral blood lymphocytes or human bone marrow cells and daily injections of rhGH (20 micrograms ip every other day). Upon later assessment for engraftment by flow cytometric analysis, it was determined that rhGH strongly promoted human T-cell engraftment in the thymus and spleens of these mice. However, there was considerable variability in both the incidence and extent of engraftment which appears to be due to donor-to-donor variation. Additionally, rhGH promoted B lymphomagenesis in these mice since long-term treatment of these xenogeneic chimeras with rhGH resulted in the increased incidence of human Epstein-Barr virus (EBV)-infected B-cell lymphoma. Thus, while rhGH can be used to optimize human T-cell engraftment in SCID mice, it also increases the likelihood of B-cell lymphoma generation when the donor is EBV infected. The results suggest that the activation of human T cells by rhGH results in an increased ability of these cells to traffic to the peripheral lymphoid organs of the SCID mice and results in a lymphoid microenvironment conducive to the outgrowth of EBV-transformed B lymphocytes.

Animals↗
PubMed1992

Prognostic reliability of somatosensory and visual evoked potentials of asphyxiated term infants.

The purpose of this study was to determine whether SEPs would improve the predictive power of VEPs for the prognosis of asphyxiated infants. 57 term infants had SEPs and VEPs recorded during the first three days of life, during the first week and at follow-up visits. All survivors have been followed for 18 to 24 months. 34 had a normal outcome, 12 had severe neurological sequelae and 11 died. The SEPs had both high sensitivity (96 per cent) and negative predictive power (97 per cent); normal SEPs virtually guaranteed normal outcome. The VEPs had both a specificity and positive predictive power of 100 per cent; abnormal VEPs guaranteed abnormal outcome. Both together had a higher predictive power than either alone. The combination of VEPs and SEPs yields a powerful means of prognostication for term asphyxiated infants; the results suggest that both be included in the assessment of this population.

Asphyxia Neonatorum↗
PubMed1990

An absence of T cells in murine bone marrow allografts leads to an increased susceptibility to rejection by natural killer cells and T cells.

The mechanisms behind the increased incidence of marrow graft failure in recipients that receive allogeneic marrow depleted of T cells were studied. Recipient mice were lethally irradiated and challenged with bone marrow cells (BMC) from C.B-17 +/+ (+/+) donors. Radioisotope 125IUdR incorporation was assessed 5 to 7 days after transfer to determine the extent of engraftment. Some groups received BMC in which the T cells were removed by treatment with antibody and C. In addition, some groups received BMC from T cell-deficient C.B-17 scid/scid (SCID) mice to determine the postulated need for donor T cells in hematopoiesis and engraftment. In a model system that distinguishes between possible host NK cell and radioresistant T cell-mediated rejection of marrow allografts, it was determined that the absence of donor T cells in a marrow graft does not affect engraftment in syngeneic recipients. However, both host NK cell and radioresistant T cell rejection was markedly enhanced when SCID BMC or BMC from C.B-17 +/+ donors that had T cells removed by antibody and complement were infused into irradiated allogeneic recipients. Furthermore, the addition of alloreactive thymocytes as a source of T cells could abrogate this increased susceptibility of the BMC to host rejection mechanisms. As determined by histology and 59Fe uptake, the addition of thymocytes resulted in enhanced erythropoiesis. These results suggest that the increased incidence of marrow graft failure when BMC depleted of T cells are used is a result of active rejection by host effector cells and that the adverse effect of marrow T cell depletion can be reversed by the addition of thymocytes.

Animals↗
PubMed1990

Natural killer cells activated with interleukin 2 in vitro can be adoptively transferred and mediate hematopoietic histocompatibility-1 antigen-specific bone marrow rejection in vivo.

An adoptive transfer model was developed for examining natural killer (NK) cell-mediated bone marrow cell (BMC) graft rejection. Homogeneous populations of NK cells were obtained by culturing spleen cells from mice with severe combined immune deficiency in the presence of recombinant interleukin 2 for 7 days. These cells maintained a phenotypic (CD3-CD4-CD8-NK-2.1+ and asialo GM1+) and lytic pattern consistent with that of activated NK cells. The cells were infused into lethally irradiated recipients whose own NK cells were depleted by anti-NK-1.1 antibody treatment and could no longer reject marrow allografts. The transferred NK cells restored the ability of the hosts to reject BMC in a hematopoietic histocompatibility-1 (Hh-1) antigen-specific manner. Immunogenetic studies demonstrated that the rejection was a function of the donor, not host, NK cells. These studies demonstrate that NK cells can be cultured in vitro with recombinant interleukin 2 and are capable of mediating Hh-1-specific BMC rejection in vivo in the absence of other immune cell types.

Animals↗
PubMed1989

A transcriptional analysis of the Trypanosoma brucei hsp83 gene cluster.

Ten to twelve copies of the 83-kDa heat-shock protein gene (hsp83) from Trypanosoma brucei are arranged in a head-to-tail tandem array of 2.8-kb repeat units, which are transcribed to give 2.6-kb mature mRNAs. We have cloned and sequenced one of the repeat units. The gene encodes a putative protein of 81 kDa which is highly homologous to Hsp83 of Drosophila melanogaster (75%), Hsp90 of Saccharomyces cerevisiae (72%) and the C62.5 protein of Escherichia coli (61%). The 5' end of the mature mRNA was mapped by primer extension sequence analysis and shown to contain the spliced leader. The mapping of the 3' poly(A) addition sites by S1 analysis indicated that there is 218 nt of intergenic sequence linking the boundaries encoding the mature mRNA. Within this sequence are a number of elements conserved with the trypanosome hsp70 intergenic region, including a 14-nt sequence that also has homology to the Drosophila heat-shock consensus element.

Amino Acid Sequence↗
PubMed1987

Acute rejection of murine bone marrow allografts by natural killer cells and T cells. Differences in kinetics and target antigens recognized.

Lethally irradiated C.B-17 +/+, C.B-17 scid/scid (severe combined immunodeficiency, SCID), BALB/c-nu/nu (nude), and C57BL/6 (B6) mice were challenged with H-2-homozygous or H-2-heterozygous totally allogeneic bone marrow cell (BMC) grafts. Some of the irradiated mice were immunized simultaneously with large numbers of irradiated marrow and spleen cells syngeneic with the viable BMC transferred. Irradiated SCID and nude mice, devoid of T cells but with normal NK cell function, were able to reject H-2-homozygous BMC grafts within 4 d. However, they were unable to reject H-2-heterozygous BMC allografts by 7 d even if they were immunized. B6 and C.B-17 +/+ mice were able to reject H-2 heterozygous BMC allografts by 7-8 d, but not as early as 4 d, if they were immunized. The rejection of H-2-homozygous BMC on day 4 was inhibited by administration of anti-NK-1.1 antibodies, but not by anti-Lyt-2 antibodies. Conversely, the rejection of H-2-heterozygous allogeneic BMC on day 8 was prevented by anti-Lyt-2 but not by anti-NK-1.1 antibodies. The data indicate that both NK cells and Lyt-2+ T cells can mediate rejection of allogeneic BMC acutely, even after exposure of mice to lethal doses of ionizing irradiation. NK cells appear to recognize Hemopoietic histocompatibility (Hh) antigens on H-2 homozygous stem cells. The inability of SCID and nude mice to reject H-2 heterozygous totally allogeneic BMC indicate that NK cells do not survey donor marrow cells for self H-2 antigens and reject those cells that express nonself H-2 antigens. The T cells presumably recognize conventional H-2 antigens (probably class I) under these conditions.

Animals↗
PubMed1987

Rejection of bone marrow allografts by mice with severe combined immune deficiency (SCID). Evidence that natural killer cells can mediate the specificity of marrow graft rejection.

C.B-17 scid (H-2d) mice are homozygous for the gene that causes severe combined immune deficiency (SCID). These mice have no T or B cell function, yet display normal natural killer (NK) activity. Irradiated SCID mice were challenged with marrow grafts to determine if antibodies are necessary for marrow allograft rejection. SCID mice rejected H-2/Hh-1 allogeneic marrow grafts. Moreover, this rejection capability could be adoptively transferred using SCID marrow as a source of NK progenitors infused into irradiated B6 (H-2b) hosts. We conclude that NK cells can mediate marrow allograft reactivity in the absence of immunoglobulin. It follows that NK cells probably have specific receptors for Hh antigens.

Animals↗
PubMed1986

Identification of a novel Y branch structure as an intermediate in trypanosome mRNA processing: evidence for trans splicing.

We present evidence that addition of the 35 nucleotide spliced leader (SL) to the 5' end of T. brucei mRNAs occurs via trans RNA splicing. A 100 nucleotide fragment of the 135 base SL RNA (100-mer) is revealed by S1 nuclease analysis of total and poly(A)+ RNA. This 100-mer is not detected by Northern hybridization analysis, indicating that it does not exist free in the cell. The 5' end of the 100-mer maps precisely to the conserved splice junction sequence of the SL RNA. Purified debranching enzyme releases this 100-mer RNA as a free, 100 nucleotide species. This indicates that the 100-mer is covalently linked to poly(A)+ RNA by a 2'-5' phosphodiester bond, that the branched intermediate has a discontinuous intron or Y structure (rather than a lariat), which is expected of a trans-spliced mRNA, and that the SL RNA is indeed the donor of the SL sequence to trypanosome mRNAs.

Animals↗
PubMed1984

Structure of the 5' ends of immunoglobulin genes: a novel conserved sequence.

Recent investigations have suggested that tissue-specific regulatory factors are required for immunoglobulin gene transcription. Cells of the mouse lymphocytoid pre-B-cell line 70Z/3 contain a constitutively rearranged immunoglobulin kappa light chain gene; the nucleotide sequence of this gene exhibits all the known properties of a functionally competent transcription unit. Nevertheless, transcripts derived from this gene are detectable only after exposure of the cells to bacterial lipopolysaccharide, implying that accurate DNA rearrangement is not sufficient to activate expression of the gene. Comparison of the sequence of the 70Z/3 kappa light chain gene with those encoding other immunoglobulin heavy and light chains has revealed that a distinctive promoter region structure is characteristic of this multigene family. The sequence A-T-T-T-G-C-A-T lies approximately 70 base pairs upstream from the site of transcriptional initiation in every light chain gene examined; in heavy chain genes, the corresponding location is occupied by the precise inverse (A-T-G-C-A-A-A-T) of this sequence. Although adjacent regions of DNA have diverged extensively in evolution, these octanucleotide sequences are stringently conserved at this location among diverse immunoglobulin genes from at least two mammalian species. The proximity of this conserved octanucleotide block to the site of transcriptional initiation suggests that it may serve as a recognition locus for factors regulating immunoglobulin gene expression in a tissue-specific fashion.

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