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Biomedical subjects

R Andreesen

Publications and source records attributed to R Andreesen.

At least 127 records · Page 7Linked to original sources
PubMed1990

Systematic classification of HIV biological subtypes on lymphocytes and monocytes/macrophages.

The growth properties and cytopathic effects of several HIV-1 and HIV-2 strains were compared between cultures on human lymphocytes and monocytes/macrophages, respectively. For some isolates (among these three paired isolates from blood and cerebrospinal fluid) replication and cytopathogenicity were comparable between lymphocytes and monocytes/macrophages (dual tropic viruses), while others showed a very specific tropism for only one cell type. Yet another subtype grew neither well on lymphocytes nor on macrophages. Taking into account the growth properties in monocytes/macrophages we propose a classification system for HIV subtypes on these cells (alpha-delta), in analogy to the nomenclature for HIV-subtyping on lymphocytes (a-d). Using this system, some prototypic viruses (LAV/HTLV-IIIB, HIV-2ROD, SIVBK28, HIV-2ALT) as well as several other HIV-1 and HIV-2 isolates were subtyped.

Cells, Cultured↗
PubMed1990

Biological response to intravenously administered endotoxin in patients with advanced cancer.

The purpose of the study was to evaluate the toxicity and biological activity of highly purified lipopolysaccharide (LPS) administered intravenously to cancer patients in order to establish an optimum dosage scheme. An initial subtoxic dose was increased in weekly increments in accordance with individual regimens that maintained patient reaction at a safe and acceptable level. Purified LPS from Salmonella abortus equi was administered to 11 patients with advanced solid tumors on a weekly schedule with intraindividually escalating dosage as determined by patient response. Biological response was monitored by complete blood count, C-reactive protein, and cytokine measurements at different time points after LPS injection. Tumor necrosis factor-alpha (TNF) and interleukin-1 beta serum levels were measured by enzyme-linked immunosorbent assay and interleukin-6 (IL-6) by bioassay. Dose-limiting toxicities including chills and fever (WHO grade III) were reached at 1.0 ng/kg of body weight (maximal tolerated dose-1, MTD-1). Pretreatment with ibuprofen (1,600 mg) abrogated these side effects, allowing further escalation of LPS doses up to 10 ng/kg of body weight. At dose levels greater than 8.0 ng/kg of body weight (MTD-2), the aforementioned side effects occurred again and, additionally, hepatic toxicity (WHO grade III) was observed. Hematological changes included neutropenia followed by a pronounced neutrophilia contributed to by up to 30% bands, marked monocytopenia for 3 h, and retarded lymphopenia. By 24 h, all hematological parameters returned to pretreatment values. TNF serum levels increased from 10 pg/ml before treatment to 7,000 pg/ml as a function of dosage. Maximum serum levels were reached at 60 to 90 min after LPS injection. Similarly, IL-6 serum concentrations increased from less than 4 to 2,500 U/ml; peak levels were obtained 30 min after TNF peak values. Prior administration of ibuprofen had no effect on the above-mentioned hematological changes nor on cytokine release. LPS can be administered intravenously in weekly intervals at escalating doses from 0.15-10.0 ng/kg of body weight, when patients are protected by pretreatment with ibuprofen at dose levels above 1.0 ng/kg of body weight. Cytokine release as measured by TNF and IL-6 increased in a dose-dependent manner although the constitutional symptoms are completely attenuated.

Adult↗
PubMed1990

Sequential studies on the role of mitoxantrone, high-dose cytarabine, and recombinant human granulocyte-macrophage colony-stimulating factor in the treatment of refractory non-Hodgkin's lymphoma.

Mitoxantrone (Novantrone, American Cyanamid Company; NO) and high-dose cytarabine (Ara-C; AC) have each been shown to be active in non-Hodgkin's lymphomas (NHL) in various studies. The studies reported here are sequential. The first study (NOAC I) combined high-dose cytarabine (3 g/m2/12 h as a 3 h infusion on day 1) with mitoxantrone (10 mg/m2/d on days 2 and 3). Of 31 patients with relapsed and refractory NHL, 7 achieved complete remission (CR) and 7, partial remission (PR). Myelosuppression was the major toxicity of this regimen. In the second study (NOAC II), the dosage of cytarabine was escalated to 3 g/m2/12 h on days 1 and 2 (4 doses) while mitoxantrone remained 10 mg/m2/d on days 2 and 3. The effects of recombinant human (rh) granulocyte-macrophage colony-stimulating factor (GM-CSF) were simultaneously studied. Twenty-three patients from five centers were treated with NOAC plus rhGM-CSF while 14 patients from four centers received NOAC II alone. A CR was achieved in 9 of 23 patients who received the additional rhGM-CSF and in 2 of 14 patients treated with NOAC alone. With rhGM-CSF, the median duration of severe neutropenia (less than 0.5/nL) after chemotherapy was 8 days versus a median of 13 days without rhGM-CSF, while the duration of severe thrombocytopenia (less than 20/nL) was not significantly different. The rates of infection and mucositis were 25% and 17%, respectively, with rhGM-CSF compared to 53% and 60% without rhGM-CSF. Thus, this last nonrandomized pilot study indicates that administration of rhGM-CSF reduces the duration of chemotherapy-induced cytopenia and the rate of mucositis. This growth factor does not appear to result in stimulation of lymphoma cells. At present, a controlled randomized trial is being conducted using NOAC II with rhGM-CSF or placebo to establish the definitive role of this growth factor in the treatment of NHL.

Adolescent↗
PubMed1989

Defective monocyte-to-macrophage maturation in patients with aplastic anemia.

Macrophages (MAC) are important effector cells of the immune system but also play an essential role as regulatory cells in hematopoiesis. They originate from circulating monocytes (MO) as immature precursor cells that undergo terminal differentiation upon migration from the capillary bed into the various tissues. In the presence of serum, MAC maturation from blood MO is observed in vitro and can be followed by the expression of maturation-associated antigens (MAX.1, .3, .11, and .26; transferrin receptor, 13C2, CD16). We have tested blood MO from 22 patients with aplastic anemia (AA) for their capacity to undergo terminal maturation in vitro. After isolation, blood MO in six patients expressed CD14 molecules at low density when compared to normals. On culture for 7 days, in 15 patients various abnormalities could be shown by phenotype analysis using cell-enzyme-linked immunosorbent assay (ELISA) and an immunoperoxidase staining technique of single cells. Abnormalities ranged from the distinctive failure of mature MAC to express single surface antigens (eg, gp64-MAX.1) to complete inhibition of the development of a MAC maturation-associated phenotype. In three patients the maturational defect was found to persist in complete remission after successful therapy with antileukocyte globulin (ALG). Neither in other immunosuppressed or multiple-transfused patients nor in those with bone marrow hypoplasia secondary to cancer chemotherapy and during hematologic reconstitution following autologous bone marrow transplantation (BMT), defective MO maturation in vitro was seen. Our data provide evidence for the existence of serious disorders within the MO-MAC lineage in patients with AA. This observation may either reflect the stem-cell defect or indicate a MAC involvement in the pathogenesis of the disease.

Anemia, Aplastic↗
PubMed1989

Human macrophages can express the Hodgkin's cell-associated antigen Ki-1 (CD30).

The normal precursor of the neoplastic cell in Hodgkin's lymphoma is still unknown. Previous reports on the expression of the Hodgkin's cell-associated antigen Ki-1, CD30, on normal cells have been limited to activated lymphocytes. This study demonstrates, however, that cells of the macrophage lineage also are able to express the Ki-1 antigen. The Ki-1 antigen is absent from normal blood monocytes but expressed on up to 85% of macrophage-type cells developed during subsequent in vitro differentiation on Teflon membranes. Unlike other maturation-associated antigens, Ki-1 is found only at late stages of the macrophage primary cultures. Its expression can be enhanced by human interferon-gamma in a fashion similar to that of HLA-DR molecules. In addition, freshly explanted tumor cells from three patients with histopathologic and clinical features consistent with the diagnosis of true histiocytic lymphoma or malignant histiocytosis as well as the permanent cell line SU-DHL-1 could be demonstrated to express the Ki-1 antigen. The phenotype of histiocytic malignancy was further evaluated to be HLA-DR+MAX.26+CD25+-EMA+OKT9+Ki-1+. The results could indicate either that Hodgkin's lymphoma may arise not only from the lymphocyte but also from the macrophage lineage or may emphasize a macrophage involvement in the pathogenesis of this disease.

Antibodies, Monoclonal↗
PubMed1988

Human macrophage maturation and heterogeneity: restricted expression of late differentiation antigens in situ.

Terminal maturation of human macrophages is an important step for creation of cell diversity amongst site-specific subpopulations and their functional competence in situ. As monocytes undergo differentiation in vitro, they start to express lineage-restricted antigens specific for differentiation stages beyond the blood monocyte level as detected by monoclonal antibodies of the MAX series. We have analyzed the expression of MAX.1, MAX.2, MAX.3 and MAX.11 on exudate-type macrophages from pleural and peritoneal cavity and the alveolar space, as well as on resident and activated tissue macrophages in cryostat sections of spleen, lymph node, tonsil, liver, gut mucosa, skin, placenta, kidney and bone. It was found that "free" macrophages in serous cavities expressed MAX antigens in a heterogenous pattern, whereas none of the organ-specific tissue macrophages subsets did so (with the exception being the weak label of MAX.2 on Kupffer cells). Only during allograft rejection were infiltrating macrophages found to express MAX antigens but not at sites of "non-specific" inflammation or granuloma formation. However, Cyclosporin A treatment seems to suppress the induction of MAX antigen expression on intragraft macrophages. In addition, freshly harvested MAX-negative exudate macrophages converted to the complete Max+ phenotype on further cultivation. Isolated Kupffer cells were able only to express the MAX.2 antigen in culture but still did not react with the MAX.1 and MAX.3 monoclonal antibodies. Some MAX antigens are co-expressed on glomerular mesangial cells, dendritic reticulum cells and placental cells (MAX.1/.11) as well as on capillary endothelium within tissues of active immune response (MAX.2).(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1988

Human macrophage maturation in vitro: expression of functional transferrin binding sites of high affinity.

Human blood monocytes (mo) when cultured in suspension on hydrophobic teflon membranes undergo terminal maturation to macrophages (MO). Together with the appearance of new lineage-restricted differentiation antigens, mature MO but not blood mo, express transferrin (TF) receptor molecules as detected by immunostaining methods. Here we report that radio- and fluorescein-labelled TF binds to a single class of high-affinity binding sites on MO but not on mo. As mo mature in vitro in the presence of human serum, their receptor numbers increase to about 10(6) per cell, showing an apparent Kd for Fe2TF of approximately 5 nM. These receptor numbers were comparable with our estimates for cultured K 562 human tumor cells, and about 20x greater than reported for human MO cultured in the presence of fetal calf serum. Our MO showed 58Fe uptake comparable with uptake by tumor cells and also exhibited TF-promoted uptakes of 61Ga. The possibility that MO might recycle stored iron through receptor-bound apoTF was not supported by experiments which showed that their Fe2TF receptors had much lower affinity for apoTF (Kd greater than 1 microM) and which could not detect separate high-affinity receptors specific for apoTF. Expression of TF receptors was not substantially altered by treatment with human recombinant interferon-gamma.

Cell Division↗
PubMed1988

Activation of human monocyte-derived macrophages cultured on Teflon: response to interferon-gamma during terminal maturation in vitro.

Macrophages (M phi) are potential antitumor effector cells derived from circulating blood monocytes (mo). Most studies on human mo/M phi biology and function have been performed using immature mo precursor cells. However, the conclusions drawn may be questionable, as mo have to undergo terminal differentiation before they reach relevant tissue sites of inflammation and immune reaction. We have analyzed the ability of mo-derived, teflon-cultured M phi to respond to activating stimuli with an increased tumor cytotoxic effector cell function using recombinant interferon-gamma (IFN-gamma), IFN-alpha 2, granulocyte/macrophage colony stimulating factor (GM-CSF), interleukin(IL) 2, IL 1 alpha, and bacterial lipopolysaccharides (LPS) as mediator molecules. It could be shown that the response of M phi to the most potent activator molecule, IFN-gamma, depends on the terminal differentiation from the mo stage to the mature M phi. Whereas adherent mo could be activated only moderately, M phi increased their cytotoxicity by a factor of up to 400. IFN-gamma activation positively correlated with the effector cell number, the time of incubation and the dosage used. Activation did not depend on the presence of LPS, and was lost within 24 to 48 h. LPS itself activated cells only in the microgram range. IFN-alpha 2 activated M phi only at a two log higher concentration than IFN-gamma; GM-CSF was only slightly effective, whereas M phi incubation with IL 1 alpha or IL 2 did not result in M phi activation. Thus, the ability of human M phi to become activated appears to be a function of cellular maturation and is acquired during the terminal step of M phi differentiation. Teflon-cultured M phi could facilitate studies of the activation of human M phi and may be more suitable cells for adoptive immunotherapy in cancer patients than blood monocytes.

Cell Differentiation↗
PubMed1988

Microculture assay for human macrophage maturation in vitro. Cell-ELISA analysis of differentiation antigen expression.

The terminal differentiation of monocytes (mo) to macrophages (MO) is essential for the complex functioning of the mononuclear phagocyte system. Similar to in vivo MO maturation, blood mo transform to MO when cultured in vitro. This offers a model system for experimental studies of functional defects within this cell lineage. In order to develop a microassay for the evaluation of MO maturation in vitro we monitored the antigenic phenotype of MO during differentiation in vitro. The cells were grown either in suspension on hydrophobic Teflon foils, or as plastic adherent monolayers. Surface antigens were visualized on single cells with the immunoperoxidase slide technique or quantitated with the enzyme-linked immunosorbent assay (ELISA). As MO mature in vitro they increase in cell size, in the amount of beta-2-microglobulin, the myeloid antigen CD14 and HLA-DR antigen expression as measured with cell-ELISA, both in microwell cultures and on single cells. Upon terminal differentiation mo-MO express differentiation-specific antigens (transferrin receptor, surface transferrin and antigens of the Max series) which are indicative of a successful MO maturation. Monocyte cultures in microplates and the subsequent evaluation of differentiation antigen expression could be used as an experimental system to study the modulation of MO differentiation in vitro and may serve as an in vitro parameter of MO function in vivo.

Antigens, Differentiation↗
PubMed1987

Differential effects of ether lipids on the activity and secretion of interleukin-1 and interleukin-2.

Alkyl lysophospholipids (ALP) are synthetic analogues of lysophosphatidylcholine and represent a new generation of antitumor drugs currently being tested in phase-I trials in patients with cancer. The present study reports the differential modulation of human immunocompetent cells in vitro by ALP. Serum-bound ALP effectively blocked the response of growth factor-dependent cells to interleukin-2 (IL-2), inhibited the cellular production and release of IL-2 and suppressed the comitogenic effect of interleukin-1 (IL-1) on mouse thymocytes. In contrast, ALP-primed, monocyte-derived macrophages (MO) lost their ability to release IL-1 in response to stimuli like lipopolysaccharides (LPS) during terminal maturation from monocytes. Supernatants from ALP-primed, LPS-induced MO possessed costimulatory as well as direct mitogenic activity. Neither ALP alone nor ALP-conditioned MO supernatants stimulated mouse thymocytes. Priming of MO by ET-18-OH, an ALP molecule not substituted in the sn-2 position, occurred at concentrations 4- to 16-fold higher than the most active compounds ET-18-OCH3 and the thioether analogue BM 41.440. ALP also primed MO for subsequent activation of tumor cytotoxicity by LPS and interferon-gamma. IL-1 has multiple biological activities in common with ALP, and it may mediate antitumor activity and other ALP effects in vivo. The ability of ALP to induce differential immunomodulation, as demonstrated in this study, may make ALP worthy of study for the therapy of both autoimmune and neoplastic disease.

Animals↗
PubMed1986

HLA-DR antigens on human macrophages from bronchoalveolar lavage fluid.

The expression of HLA-DR (Ia-like) antigens on human macrophages was investigated by analyses of cells from bronchoalveolar lavage fluid obtained from 12 patients with pulmonary sarcoidosis, six patients with extrinsic allergic alveolitis, nine patients with cryptogenic fibrosing alveolitis, 11 normal non-smokers, and 12 normal smokers. The HLA-DR antigen was demonstrated by the mouse monoclonal antibody OKIa by a peroxidase-antiperoxidase method performed on glass slides. No differences were found in the percentage of alveolar macrophages that expressed DR antigens between the five study groups. OKIa positivity was observed on more than 90% of macrophages in all cases. These observations suggest that the previously reported enhanced antigen presentation by alveolar macrophages in sarcoidosis is not linked with an increase in the percentage of DR+ macrophages in the lung.

Adult↗
PubMed1986

Human macrophage maturation and heterogeneity: analysis with a newly generated set of monoclonal antibodies to differentiation antigens.

We have analyzed the expression of late differentiation antigens during terminal in vitro maturation of human macrophages (M phi) from blood monocytes (MO) in comparison to their distribution among mature M phi residing in various tissue sites. By immunizing mice with M phi derived from blood MO by culture on hydrophobic Teflon foils, monoclonal antibodies (mAbs) were developed (MAX.1, MAX.2, MAX.3, MAX.11) that reacted with lineage-restricted differentiation antigens. These antigens were expressed exclusively on M phi or were markedly increased after in vitro differentiation. The only overlap to another hemopoietic cell lineage was observed with MAX.3, which is shared by platelets and megakaryocytes. In the course of M phi maturation in vitro, the MAX.1 and MAX.3 antigens are detected within the cytoplasm two days before they appear on the cell surface. In contrast, the MAX.11 antigen is expressed simultaneously in the cytoplasm and at the cell surface, is found in varying degrees on a minor portion of blood MO and U937 cells, and is expressed rapidly at high density during early M phi differentiation in vitro. Among conventional mAbs that do not react with MO we found those against the transferrin (TF)-receptor, the BA-2, and the PCA1 antigen to label M phi. M phi matured in vivo and isolated from body fluids were positive with some but not all MAX mAbs. Distinctive patterns were observed with pulmonary M phi, exudate M phi from pleural and peritoneal effusions, synovial fluids, and early lactation milk. M phi from the alveolar space, for example, constantly expressed the MAX.2 antigen but not the MAX.3 antigen. Pleural effusion M phi, however, did not react with the MAX.1 mAb, but in most cases, it did react with the MAX.3 mAb. The detection of novel differentiation antigens, all expressed on monocyte-derived M phi but differently expressed on site-specific M phi in situ, underlines the remarkable heterogeneity among human M phi. The expression of these antigens is flexible because those MAX antigens that were not expressed in situ could be induced if cells from distinct tissue sites were cultured in vitro for several days. MAX mAbs may be of potential value to study both the sequential stages of maturation within the M phi lineage as well as differential developments induced by various culture conditions in parallel to environmental factors in vivo.

Animals↗
PubMed1985

Clonogenicity of normal and malignant hematopoietic progenitor cells after exposure to synthetic alkyl-lymphospholipids.

Alkyl-lysophospholipids (ALP) are synthetic analogues of natural lysophosphatidylcholine and represent a new class of anti-tumor agents. They are cytotoxic in vitro with a high selectivity for neoplastic cells which, in contrast to normal cells, lack an alkyl-cleavage enzyme to degrade the adsorbed ALP molecules. As ALP accumulates, it interferes with normal membrane phospholipid turnover and eventually causes disruption of membrane integrity. To evaluate the potential value of ALP in eliminating leukemic cells from remission marrows prior to autologous transplantation, we tested the effect of various ALPs on the clongenicity of normal human marrow cells and on promyelocytic leukemia HL-60. A remarkable difference in the dose response to ALP of normal marrow cells an HL-60 was observed. After an incubation period of 24 h, the same inhibition of clonogenicity in HL-60 occurred at ALP concentrations 4 times lower than in normal marrow cells. Reducing the exposure time to 6 h enhanced the selectivity further: whereas HL-60 colonies were nearly completely inhibited at 16 micrograms ALP/ml, more than 50% of normal CFU-c and BFU-E were recovered after incubation with 48 micrograms/ml. No further increase in selectivity was achieved by changing the incubation temperature. Both thioether- and alkyl-analogues were active and no difference was observed between methoxy- and acylamino-substituted ALPs. We conclude that this selective cytotoxicity makes ALP compounds worth further study as purging agents in autologous bone marrow transplantation programs.

Animals↗
PubMed1985

Monoclonal antibodies against differentiation antigens on human macrophages.

Human macrophages matured in vitro from blood monocytes without additional exogenous activation were used to produce monoclonal antibodies (mAbs). Ten of them were selected for high avidity and the best discrimination between mature macrophages and a panel of other cells including freshly prepared monocytes, B cells, T cells, granulocytes and thrombocytes. Five mAbs (MAX. 1, MAX. 2, MAX. 3, MAX. 11, MAX. 24) were found to detect macrophage differentiation antigens. One mAb (MAX. 26) detects an antigen which is shared by mature macrophages and T cells.

Animals↗
PubMed1985

[In vitro and in vivo studies with interleukin 2 (IL-2) and various immunostimulants in a patient with AIDS].

We report on a lethal course of an acquired immunodeficiency syndrome (AIDS) in a young female patient. She had spent her vacancies six years before diagnosis in Haiti, where a sexual intercourse with a Haitian man had occurred. Leading clinical symptoms consisted of recurrent Herpes simplex infections of the genital and perianal region as well as unexplained high temperatures. There were some typical laboratory and immunologic features of this disease with leukopenia, hypergammaglobulinemia, cutaneous anergy, a reduction of peripheral T-lymphocytes (OKT 3) and an almost complete loss of OKT 4 (helper cells) positive lymphocytes. The mitogenic response upon stimulation with allogeneic cells (MLC) or with the mitogens PHA, Con A and PWM was significantly reduced. There was no measurable interleukin-2 (IL-2) secretion of peripheral blood lymphocytes. Several immunostimulators (thymopentin, inosiplex, bestatin) were tested in lymphocyte proliferation assays in vitro. The mitogenic response could not be enhanced by neither of these substances. A clinical trial with Delimmun (inosiplex) for 14 days did not show any clinical or immunologic improvement in this patient. The intravenous application of high dose immunoglobulin G was without any observable effect. The proliferation inducing capacity of a highly purified IL-2 preparation on the AIDS cells in vitro led us to a clinical trial with this substance. We applied 100 Bödeker units of IL-2 per kg body weight and day subcutaneously for 16 days. A therapeutical effect, however, could not be observed. Cell marker analyses did not show significant changes in lymphocyte subpopulation composition under IL-2 therapy. There was an increase in the spontaneous cell proliferation 14 days after start of IL-2 therapy. The PHA- and IL-2 response of the AIDS cells, however, was unchanged. It cannot be excluded that an administration of IL-2 in earlier stages of AIDS may have beneficial effects.

Acquired Immunodeficiency Syndrome↗