Biomedical subjects

W J Murphy

Publications and source records attributed to W J Murphy.

At least 109 records · Page 6Linked to original sources

PubMed1996

Ly-49 G2+ NK cells are responsible for mediating the rejection of H-2b bone marrow allografts in mice.

NK cells can mediate the specific rejection of bone marrow but not solid tissue allografts in lethally irradiated mice. NK cells are also responsible for the phenomenon of "hybrid resistance' in which F1 hybrid H-2 heterozygous mice can reject parental H-2 homozygous bone marrow grafts. Ly-49C and Ly-49 G2 are markers identified on subsets of NK cells. While Ly-49C+ NK cells have been demonstrated to mediate the specific rejection of H-2d bone marrow allografts, the role of the Ly-49 G2+ NK subset is unclear because depletion of this subset in vivo did not affect splenic NK activity against tumor targets. Through bone marrow transplantation typing studies, we demonstrate that Ly-49 G2+ NK cells complement Ly-49C+ NK cells in that they specifically mediate the rejection of H-2b bone marrow allografts in lethally irradiated mice. In support of this, depletion of the Ly-49C+ NK subset in vivo also enhanced the ability of the mice to reject H-2b bone marrow cells suggesting that the depletion was augmenting the ability of the Ly-49 G2+ NK cells to reject the marrow allografts. Depletion of Ly-49 G2+ NK cells in F1 hybrid mice abrogated their ability to reject parental H-2b but not H-2d bone marrow grafts. Therefore, Ly-49 G2 denotes a subset of NK cells that appears to play a critical role in the recognition of H-2b bone marrow cells in allogeneic and F1 hybrid mice.

Animals↗

PubMed1996

Phylogenetic relationships within the aplocheiloid fish genus Rivulus (Cyprinodontiformes, Rivulidae): implications for Caribbean and Central American biogeography.

We examined the phylogenetic relationships of 16 northern species of the aplocheiloid genus Rivulus inhabiting the Caribbean, Central America, and South America. A total of 714 base pairs per taxon were sequenced from two segments of the mitochondrial genome, 12S rRNA and cytochrome b. Both parsimony and neighbor-joining analyses suggest an ancient vicariant origin of the Greater Antillean taxa, in addition to a quite recent dispersal of species into the Lesser Antilles from the South American mainland. Combined analyses support the monophyly of the northern South American assemblage as the sister group of a Central American/Columbian biota. However, the monophyly of the Central American biota remains uncertain. Divergence estimates for the Central American taxa are calibrated from the Last Cretaceous separation of the proto-Antilles from the Americas. These data suggest that the extant Central American taxa represent the descendants of at least two separate invasions during the Cenozoic, prior to the closing of the Panamanian isthmus. Times are consistent with the extensive evidence for reptilian and mammalian exchange throughout the Cenozoic.

Animals↗

PubMed1996

Differential in vitro and in vivo antitumor effects mediated by anti-CD40 and anti-CD20 monoclonal antibodies against human B-cell lymphomas.

The antitumor effects of CD40 and CD20 monoclonal antibodies (mAbs) were compared on various human B-cell lymphomas by using both in vitro and in vivo assays. Anti-CD40 directly inhibited the proliferation of human B-cell lymphomas in vitro, whereas anti-CD20 exerted no inhibitory effects on the growth of any lymphoma tested. These lymphomas were then injected into immunodeficient mice to examine the antitumor efficacy of these unconjugated mAbs in vivo. This xenogeneic model was used in the evaluation of various potential therapeutic agents against human cancers in an in vivo setting. Surprisingly, in contrast to its negligible effects on lymphoma growth in vitro, anti-CD20 was more efficacious than anti-CD40 in promoting the survival of mice bearing some but not all lymphoma lines. To determine whether the antitumor effects of these mAbs were direct or indirect in vivo, we concurrently treated tumor-bearing mice with mAbs to the murine Fc receptor to block antibody-dependent cell-mediated cytotoxicity (ADCC). When these neutralizing antibodies against Fc receptors were administered at the same time as mAb treatment, the antitumor effects of anti-CD20 in vivo were completely abrogated, whereas anti-CD40 treatment, although also diminished, still provided significant antitumor effects. These results indicate that the in vivo antitumor activity of the murine anti-human CD20 mAb was primarily due to ADCC by murine effector cells, which may not translate into comparable effects in humans. By contrast, anti-CD40 may be of potential clinical use in the treatment of lymphomas in humans because of its additional direct anti-proliferative effects. The results also demonstrate a possible difficulty in accurately evaluating the potential clinical efficacy of murine antibodies against human tumors in a human/mouse model system. Murine monoclonal anti-human antibodies may produce greater effects in human/mouse xenogeneic models, in which they are more likely to elicit host effector systems than when used in vivo in humans.

Animals↗

PubMed1996

Adoptive immunotherapy involving recombinant human M-CSF and R24 anti-melanoma antibody induces human T-cell infiltration into human melanoma xenografts.

Directed motion toward and infiltration of tumor masses by effector cells is essential for successful adoptive immunotherapy. A human/SCID mouse chimeric system was used to examine whether an antitumor antibody and recombinant human monocyte colony-stimulating factor (rhM-CSF) could promote human T-cell infiltration of a human tumor in vivo. Fourteen days after subcutaneous injection of the human melanoma cell line M-14 into SCID recipients, several adoptive immunotherapy regimens were initiated using activated human T cells, an anti-melanoma monoclonal antibody (MoAb) (R24), and rhM-CSF. Effects on tumor growth and human T-cell infiltration into the tumor were assessed. Compared with other treatment groups, only mice treated with the combination of activated human T cells, anti-tumor MoAb, and rhM-CSF demonstrated a significant cellular infiltrate in the melanoma. Immunohistology demonstrated human T cells present in the tumor up to 7 days after injection. Groups treated with rhRANTES or rmGM-CSF in place of rhM-CSF exhibited markedly less human T-cell infiltration. Additionally, only mice treated with human T cells, R24, and rhM-CSF demonstrated a significant antitumor response in vivo. This model suggests that activated human T cells can be specifically targeted to in vivo tumor sites by combined treatment with an antitumor antibody and rhM-CSF.

Animals↗

PubMed1996

Relaxation dynamics of spontaneous otoacoustic emissions perturbed by external tones. III. Response to a single tone at multiple suppression levels.

The relaxation dynamics of spontaneous otoacoustic emissions (SOAEs) interacting with an external tone have been successfully described using a van der Pol limit cycle oscillator model [Murphy et al., J. Acoust. Soc. Am. 97, 3702-3710 (1995) and Murphy et al., J. Acoust. Soc. Am. 97, 3711-3720 (1995)]. Data were collected for an SOAE interacting with a single-frequency ipsilateral suppressor. Transitions between different suppressed states were achieved by adding or removing signal at the suppressor frequency. The relaxation dynamics of the van der Pol model provided a good fit to the data.

Humans↗

PubMed1995

In vivo antitumor effects of unconjugated CD30 monoclonal antibodies on human anaplastic large-cell lymphoma xenografts.

CD30 is a M(r) 120,000 surface antigen identified originally by the Ki-1 monoclonal antibody (moAb) against primary and cultured Reed-Sternberg cells present in Hodgkin's disease and anaplastic large-cell lymphomas (ALCLs). Examination of two ALCL cell lines (Karpas 299 and Michel) demonstrated cell surface expression of CD30. Incubation of these lymphomas with two anti-CD30 moAbs that recognize the ligand-binding site (M44 or HeFi-1) resulted in significant growth inhibition in vitro, with significant decreases in cell viability. Another anti-CD30 moAb, Ber-H2, which recognizes a determinant not involved in ligand binding, had no effect on ALCL growth in vitro. When these human ALCL lines were transferred i.v. into mice with severe combined immune deficiency, the mice developed extensive metastasis in the s.c., brain, or eye tissues. The treatment of mice with either M44 or HeFi-1 anti-CD30 moAbs resulted in significant increases in survival, with some mice remaining disease free for more than 100 days. Thus, anti-CD30 treatment is efficacious for CD30+ ALCL cell lines in vivo, and unconjugated anti-CD30 moAbs may be of potential clinical use.

Adult↗

PubMed1995

NK cell subsets in the regulation of murine hematopoiesis. I. 5E6+ NK cells promote hematopoietic growth in H-2d strain mice.

NK cells are able to reject bone marrow allografts in lethally irradiated mice. 5E6 is a marker expressed on a subset of NK cells that is responsible for the rejection of H-2d homozygous bone marrow cell (BMC) allografts. This suggests that the 5E6+ NK cell subset somehow recognizes and is deleterious for H-2d BMC. However, unlike Ly-49+ NK cells, 5E6+ cells are not deleted or even down-regulated in H-2d-homozygous mice. We wanted to determine, therefore, the role of the 5E6+ and 5E6- NK cell subsets in the normal physiologic regulation of hematopoiesis in H-2d strains of mice. Surprisingly, both in vivo depletion studies of normal mice and studies in which the subsets were purified and cultured with syngeneic BMC in vitro demonstrated that in H-2d mice, the 5E6+ subset of NK cells did not inhibit, but instead promoted, growth of H-2d BMC. Depletion of the 5E6+ subset also resulted in decreased marrow engraftment after syngeneic bone marrow transplantation in H-2d mice. Analysis of the cell culture supernatants of the purified subsets indicated that the functional effects of the subsets on hematopoiesis correlated with the relative amounts of hematopoietic growth-promoting cytokines produced by the NK cells. These results demonstrate that physiologically relevant subsets of NK cells exist that are involved in the homeostatic regulation of hematopoiesis and that they can be distinguished on the basis of 5E6 expression.

Animals↗

PubMed1995

Antibodies to CD40 prevent Epstein-Barr virus-mediated human B-cell lymphomagenesis in severe combined immune deficient mice given human peripheral blood lymphocytes.

CD40 is expressed on both normal and neoplastic B lymphocytes. Signal transduction through CD40 in vitro has been shown to exert stimulatory effects on normal B cells and inhibitory effects on Epstein-Barr virus (EBV)-induced B-cell lymphoma lines and some other cell lines derived from patients with aggressive histology lymphoma. The transfer of normal human peripheral blood lymphocytes (huPBL) from EBV-seropositive donors into severe combined immune deficient (SCID) mice has been previously shown to result in the generation of human B-cell lymphomas. These tumors are similar to the highly aggressive EBV-induced lymphomas that can arise clinically after transplantation or in the setting of immunodeficiency. Treatment of huPBL-SCID chimeric mice with anti-CD40 or anti-CD20 monoclonal antibodies (MoAb) significantly delayed the development of EBV-induced B-cell lymphoma. However, the effects of the two MoAb were mechanistically distinct. Anti-CD40 treatment prevented lymphoma generation, while still allowing for functional human B-cell engraftment in the huPBL-SCID mice compared with mice receiving no treatment, all of which succumbed to lymphoma. By contrast, treatment with anti-CD20 significantly inhibited total human B-cell engraftment in the SCID recipients, which accounted for the absence of lymphomas. In vitro assays examining the transformation of human B cells by EBV also indicated that anti-CD40 could directly inhibit EBV-transformation, whereas anti-CD20 antibodies had no effect. Thus, anti-CD40 exerts selective effects to allow for the engraftment of normal human B cells and prevent the emergence of EBV lymphomas. Stimulation of CD40 by antibodies or its physiologic ligand may, therefore, be of significant clinical use in the prevention of EBV-induced B lymphomas that may arise when EBV-seropositive individuals receive immunosuppressive regimens after transplantation or in immune deficiency states, such as acquired immune deficiency syndrome.

Animals↗

PubMed1995

A novel biologic function of serum amyloid A. Induction of T lymphocyte migration and adhesion.

In the course of an inflammatory response, the concentration of serum amyloid A (SAA), a hepatocyte-derived acute phase protein, increases up to 1000-fold above the normal level. Although SAA was previously thought to be immunosuppressive, we recently reported that SAA is a potent chemoattractant for monocytes and neutrophils. The present study shows that recombinant human (rh) SAA also induces directional migration of T cells in vitro. Phenotypic analyses revealed that CD4+ and CD8+ T cell subsets were equally responsive to rhSAA, whereas CD45RA cells were also not selectively attracted by rhSAA. The T cell chemotaxis induced by rhSAA was inhibited by pretreatment of cells with pertussis toxin, suggesting the interaction of rhSAA with a G-protein-coupled receptor species. T cells pretreated with an optimal concentration of SAA exhibited enhanced adherence to human umbilical cord endothelial cell monolayers. Subcutaneous administration of rhSAA into huPBL-SCID mice caused the infiltration of human T lymphocytes at the injection sites by 4 h. These results suggest that SAA may play an important role in recruiting T lymphocytes, as well as neutrophils and monocytes into inflammatory lesions.

Animals↗

PubMed1995

A classical enhancer element responsive to both lipopolysaccharide and interferon-gamma augments induction of the iNOS gene in mouse macrophages.

The ability of macrophages to kill some kinds of tumor cells is dependent upon the production of the free radical nitric oxide (NO) by the inducible enzyme NO synthase (iNOS; EC 1.14.13.39). Expression of the iNOS gene is induced by lipopolysaccharide (LPS) and augmented by interferon-gamma (IFN-gamma). Two regions of the iNOS promoter are known to regulate induction, a promoter proximal region I (RI) and a more distal region II (RII). Reconfiguration of RI within the iNOS regulatory region revealed its dependence upon native position and orientation for maximal activity, suggesting that it is a core promoter module, and further implicated the putative octamer element as a contributor to promoter activity. RII, however, functioned in a relatively orientation- and position-independent manner. Therefore, it had the characteristics of a classical enhancer element.

Amino Acid Oxidoreductases↗

PubMed1995

Characterization of the 5' flanking region and gene encoding the mouse interferon-gamma receptor.

The purpose of this investigation was to characterize the gene that encodes the receptor for mouse interferon-gamma (IFN-gamma R), including determination of its size, intronic boundaries and its transcription start points (tsp). The mouse IFN-gamma R gene is 22-kb long, with six introns that range in size from approx. 1 to 7 kb. The first six exons encode the extracellular and transmembrane (TM) domains of the protein, while the last exon of about 1 kb encodes most of the intracellular domain. No canonical TATA box can be found in the 5' flanking sequence of the gene, and primer extension analysis indicates multiple tsp. In addition, the gene's 5' promoter region was sequenced to identify candidate responsive elements that might regulate expression of the gene. Among the putative regulatory motifs identified by computer-assisted analysis are multiple SP1 and AP-2 sites, an NF1 and CCAAT box, as well as a potential cyclic AMP-responsive element (CRE).

Animals↗

PubMed1995

Effects of growth hormone and prolactin immune development and function.

Growth hormone and prolactin are neuroendocrine hormones that exert numerous effects on immune system function and development. Several fundamental questions are addressed in this review. Do neuroendocrine hormones affect specific immune cell types? What is the physiological significance of these effects? Can these effects be exploited clinically? While it is clear that there are indeed significant interactions between the neuroendocrine and immune systems, there are relatively few examples with demonstrated physiological significance. Present studies indicate that growth hormone and prolactin may exert markedly different effects on immune cell types depending on their stage in differentiation. Recent emphasis has also been focussed on the use of these hormones or their antagonists clinically in the treatment of AIDS, cancer, and autoimmune disease states due to their pleiotropic effects and low toxicity after systemic administration. However, we do not yet have a clear picture of how the influence of neuroendocrine hormones may be used to favorably alter pathophysiologic processes affecting immune function and development.

Animals↗

PubMed1995

Relaxation dynamics of spontaneous otoacoustic emissions perturbed by external tones. I. Response to pulsed single-tone suppressors.

The dynamic aspects of the suppression of spontaneous otoacoustic emissions by external tones are evaluated. A Van der Pol oscillator driven by an external tone is used as an interpretive model for data on the pulsed suppression of spontaneous emissions obtained from six female subjects. Typical results for both the onset of, and recovery from suppression yield 1/r1 (where -r1 is the negative linear component of the damping function) in the range of 2-25 ms. In accordance with the predictions of the model, (a) the relaxation time for the onset of suppression increases with the amount of suppression induced by the external tone, (b) the values of r1 and the amplitudes of the unsuppressed emissions exhibit an inverse correlation, (c) the values inferred for r1 are not significantly dependent on the frequency of the pulsed suppressor tone, and (d) the inferred r1 values are not significantly dependent upon the amount of suppression.

Adult↗

PubMed1995

Relaxation dynamics of spontaneous otoacoustic emissions perturbed by external tones. II. Suppression of interacting emissions.

The level of a spontaneous otoacoustic emission (SOAE) during recovery from suppression by an external tone sometimes exhibits a prominent overshoot before reaching its normal level. At the onset of suppression, a less prominent undershoot is sometimes observed before the emission level stabilizes. The overshoot and undershoot are described in terms of the variable amount suppression produced by a neighboring higher-frequency SOAE which is responding more slowly to the modulation of the external tone. The variation of the SOAE amplitude during pulsed suppression is modeled by a pair of Van der Pol limit-cycle oscillators with the primary oscillator linearly coupled to the displacement of the secondary high-frequency one. We have found relaxation time constants for the onset of suppression of the order of 4.5 and 7.4 ms for the primary and secondary SOAEs, respectively, and for the recovery from suppression 4.8 and 10.48 ms for the primary and secondary SOAEs, respectively. The same model is also successful in describing the release from suppression of the primary SOAE by the secondary SOAE when the latter is partially suppressed by the external tone. Aspirin administration reduces the magnitude of the overshoot by reducing the level of the higher-frequency SOAE and thereby eliminating the suppression of the lower-frequency one.

Acoustic Stimulation↗

PubMed1995

Epstein-Barr virus-induced human B-cell lymphoma arising in HuPBL-SCID chimeric mice: characterization and the role of CD40 stimulation in their treatment and prevention.

The transfer of human peripheral blood lymphocytes (huPBL) from EBV-seropositive donors into mice with severe combined immune deficiency (SCID) has been shown previously to result in the generation of human EBV-induced B-cell lymphomas. These lymphomas are similar to the aggressive lymphomas that arise clinically in immunocompromised individuals. We have assessed the p53 status of these human B-lymphomas and the clonality of cell lines established from tumors growing in the huPBL-SCID mice. While the lymphoma cell lines were demonstrated to be pauciclonal by Southern analysis, none of the lines demonstrated mutated p53 as determined by immunoprecipitation studies using antibodies specific for mutant p53. The cell lines were all positive for CD40, a marker present on normal and neoplastic B cells. Antibodies to CD40 significantly inhibited the growth of these EBV-transformed B-cell lymphomas both in vitro and in vivo. When partially purified human B cells were incubated with either anti-CD40 or anti-IgM in the presence of EBV-containing supernatants in vitro, only anti-CD40 prevented transformation by EBV. Treatment of huPBL-SCID mice with anti-CD40 also prevented the occurrence of the EBV lymphomas. However, long-term human B-cell engraftment was not inhibited as determined by the presence of serum human immunoglobulin in the chimeric mice. Overnight incubation of the huPBL with anti-CD40 did not prevent the incidence of lymphomas in huPBL-SCID chimeras suggesting that continuous exposure to anti-CD40 is required. These studies suggest that anti-CD40 may be of significant clinical use in the treatment or prevention of EBV-induced B-cell lymphomas.

Animals↗

PubMed1995

Monocyte chemotactic protein-1 (MCP-1), -2, and -3 are chemotactic for human T lymphocytes.

Monocyte chemotactic protein (MCP)-1, -2, and -3 all have been shown to induce monocyte/macrophage migration in vitro and MCP-1, also known as MCAF, chemoattracts basophils and mast cells. We report here that natural MCP-1 as well as synthetic preparations of MCP-2 and MCP-3 stimulate significant in vitro chemotaxis of human peripheral blood T lymphocytes. This MCP-induced migration was dose-dependent and directional, but not chemokinetic. Phenotypic analysis of the T cell population responsive to MCP-1, MCP-2, and MCP-3 demonstrates that both CD4+ and CD8+ T cells migrated in response to these chemokines. Similar results were observed using human CD4+ and CD8+ T cell clones. Neutralizing antisera to MCAF or MCP-2 abrogated T cell migration in response to MCP-1 and MCP-2, respectively, but not to RANTES. Subcutaneous administration of purified MCP-1 into the hind flanks of SCID mice engrafted with human peripheral blood lymphocytes (PBL) induced significant human CD3+ T cell infiltration into the site of injection at 4 h. These results demonstrate that MCP-1, MCP-2, and MCP-3 are inflammatory mediators that specifically stimulate the directional migration of T cells as well as monocytes and may play an important role in immune cell recruitment into sites of antigenic challenge.

Animals↗

PubMed1995

Engraftment of SCID mice by human bone marrow hematopoietic cells cultured in vitro: an in vivo model for human gene transfer.

Demonstration of the ability of fresh human hematopoietic cells to engraft severe combined immuno-deficient (scid) mice has provided an in vivo assay for expansion and maturation of early human progenitor cells. However, engraftment of cultured hematopoietic cells has been difficult to achieve. We wished to further develop this model as an in vivo assay for efficiency of retroviral gene transfer and expression in the differentiated progeny of adult human bone marrow progenitor cells. Human bone marrow cells were cultured in vitro for six days under conditions suitable for infection by retroviral vectors prior to transfer to irradiated scid mice. Cultured human bone marrow cells introduced by both intravenous (i.v.) and intraperitoneal (i.p.) injection persisted in the bone marrow, spleen and peritoneum of recipient animals up to four weeks after transfer. Following irradiation scid mice receiving cultured human bone marrow cells by either i.v. or i.p. routes demonstrated engraftment of the bone marrow and spleen as determined by the growth of human hematopoietic progenitors in soft agar. By flow cytometric analysis human cells were also detected in the peritoneum of mice receiving cultured human bone marrow cells i.p. These results suggest that the transfer of cultured human bone marrow cells to scid mice with the subsequent engraftment of these cells in the bone marrow, spleen and peritoneum of recipients can routinely occur. This provides an in vivo model for retroviral gene transfer to human cells.

Adult↗

PubMed1995

Growth inhibition and apoptosis of RL human B lymphoma cells by vitamin E succinate and retinoic acid: role for transforming growth factor beta.

Vitamin E succinate (VES) and all-trans-retinoic acid (RA) were determined to be growth inhibitory for B lymphoma cells in vitro. RL, an Epstein-Barr virus-negative human cell line, was growth suppressed 87% with VES (5 micrograms/ml) and 58% with RA (10(-6) M); both agents blocked the cells in G1 of the cell cycle. The antiproliferative effect of VES seems to be independent of its potential antioxidant property because both fat- and water-soluble antioxidants were found to have no effect on RL cell proliferation. VES and RA increased IgM antibody concentrations in cell supernatants 5.8- and 9.9-fold, respectively. DNA fragmentation and flow cytometry studies showed VES- and RA-induced apoptosis in RL cells. VES- and RA-treated RL cells gradually underwent apoptosis over time with maximal induction occurring at days 6 and 5 of culture, respectively. A role for transforming growth factor beta in VES- and RA-mediated RL growth suppression is indicated by increased ligand and type II receptor protein expression. Furthermore, neutralizing antibodies to transforming growth factor beta 1 partially blocked the growth suppressive action of both VES and RA, thus suggesting that a TGF-beta autocrine negative loop was involved in VES and RA suppression of RL cell growth.

Antibodies, Neoplasm↗