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Biomedical subjects

E Karhumäki

Publications and source records attributed to E Karhumäki.

13 recordsLinked to original sources
PubMed1993

An improved enrichment method for functionally competent, highly purified peripheral blood dendritic cells and its application to HIV-infected blood samples.

Dendritic cells (DC) were purified from human peripheral blood using a rapid and simple method based on magnetic depletion of phagocytes with carbonyl iron, followed by centrifugation of nonphagocytic cells on a Percoll density gradient and depletion of lymphocytes and macrophages/monocytes with a panel of MoAbs and immunomagnetic beads. Enriched DC were obtained with > 99% purity as judged by non-specific esterase (NSE) staining. After isolation, these cells, representing 0.4% of the starting mononuclear cell population, still function as potent antigen-presenting cells for purified T lymphocytes. The present results confirm the ability of human peripheral blood DC to present soluble antigens to T cells including microbial antigens and show, further, that DC are more potent soluble antigen-presenting cells than monocytes. The method was successfully applied to the purification of DC from the blood of HIV-infected individuals. We could not detect decreased numbers of DC in four individuals with early HIV infection and no replicating HIV was detected by in situ hybridization in the DC.

Antigen-Presenting Cells↗
PubMed1988

Chromatographic and enzymatic effects on transfer factor-like activity from human leukocytes and porcine spleen dialysate.

1. The effect of dialysable transfer factor (TFd), derived from human leukocytes or porcine spleen cells, was measured using Listeria resistance in mice. 2. The molecular weight range of substance(s) containing TF-like activity is in the less than 3500 MW dialysis fraction on the basis of the capacity of peritoneal macrophages to produce superoxide anion (O2-). This biological activity is removed by heating at 56 degrees C. 3. After Sephadex G-10 chromatography of dialysates the significant activities are found in fractions III and IV of human leukocyte dialysate and in fractions of II and III of porcine spleen dialysate. 4. From enzymatic studies, most of the protective activity of both human leukocyte and porcine spleen dialysate is based on the action of small-molecular weight structures containing peptides and/or polynucleotides.

Animals↗
PubMed1987

Cells of the human myelomonocytic line RC-2A synthesize tissue factor-like procoagulant and urokinase-type plasminogen activator.

Cells of the myelomonocytic leukemia cell line RC-2A were studied for their ability to synthesize clotting-promoting and fibrinolytic factors. The cells were observed to generate procoagulant activity (PCA) in readily measurable quantities. Incubation of RC-2A cells with phorbol myristate acetate (PMA; 3 ng/ml) or phytohemagglutinin (PHA, 10 micrograms/ml) for 18 h resulted in a 4-5-fold increase in PCA relative to unstimulated control. The PCA of RC-2A cells was tissue factor-like in that it was dependent on factor VII but not on factors VIII or IX. RC-2A cells also produced plasminogen activator (PA). Secreted PA was approximately 70% of the PA of an identical number of human monocyte-derived macrophages; fresh isolated monocytes synthesized virtually no PA. Compared to macrophages, RC-2A cells secreted less or no PA-inhibitors. Lysates of RC-2A cells contained over three times more PA than lysed macrophages. Stimulation of the cells with lectins (PHA, concanavalin A) or PMA was followed by a modest (2-3-fold) increase in PA. Enzyme immunoassay with antibodies to urokinase (u-PA) or tissue-type PA (t-PA) identified the RC-2A plasminogen activator as being of urokinase type.

Blood Coagulation Factors↗
PubMed1987

Effect of leukocyte and other tissue dialysates on NBT reduction and prostaglandin production in mice.

The effects of human leukocyte, porcine spleen and bovine liver dialysate fractions on Listeria resistance were measured by survival studies and by assessing the capacity of peritoneal macrophages to produce superoxide anion (0-2) and prostaglandins. Leukocyte (DLE) and other tissue dialysates were fractionated on a Sephadex G-10 column. Thereafter the significant activities were found in fraction III of DLE, fraction II of porcine spleen and fraction II + III of bovine liver dialysate. The treatment with active porcine spleen dialysate fraction increased the capacity of peritoneal macrophages to generate superoxide anion. On the other hand, this fraction significantly decreased the production of prostaglandin PGE2 and thromboxan B2. These results may indicate that all dialysates can be a source of a non-specifically-acting immunomodulatory preparation and that the infection-resistance-increasing substances seem to operate via the monocyte/macrophage activation.

Animals↗
PubMed1987

Regulation of oxidative metabolism by interferon-gamma during human monocyte to macrophage differentiation.

The capacity of human peripheral blood monocytes to generate highly reactive oxygen-derived molecules was studied during differentiation of the cells to macrophages in vitro. The effect of semipurified native interferon gamma (IFN gamma) on the differentiation-associated production of active oxygen intermediates was assessed by continuous exposure of the cells to IFN gamma or by adding it to the cultures at different stages of in vitro differentiation. Chemiluminescence (CL) response, triggered by opsonised zymosan, was highest in fresh isolated monocytes and fell constantly during a two-week culture. IFN gamma had little effect on CL. Generation of intracellular O2- was determined by the reduction of nitroblue tetrazolium (NBT). Zymosan-induced NBT reduction increased slightly during monocyte to macrophage differentiation and was further enhanced by continuous presence of IFN gamma. Hydrogen peroxide (H2O2) release, triggered by phorbol myristate acetate (PMA), was low in monocytes, increased slightly, reaching a maximum on day 3, and declined thereafter. H2O2 secretion was greatly enhanced by the presence of IFN gamma and remained raised for at least 14 d. When added at intervals to spontaneously matured monocytes, IFN gamma had only modest and transient effects on the generation of intracellular O2- and H2O2. It is concluded that IFN gamma seems so to modulate human mononuclear phagocyte differentiation that they maintain or increase their oxidative metabolic capacity.

Cell Differentiation↗
PubMed1985

Effect of human leukocyte and other tissue dialysates on Listeria resistance and phagocytosis in mice.

The effect of dialyzable transfer factor (TFd) on Listeria resistance was measured by survival studies and by assessing phagocytic capacity of peritoneal macrophages. Unfractionated dialysates from human leukocytes (DLE), bovine liver, porcine spleen and kidney as well as saline were injected i.p. into NMRI mice 72 h before the i.p. injection of 1-3 x 10(6) Listeria organisms. The results show that DLE, porcine spleen and bovine liver dialysate increased the LD50 5-20 times. Porcine kidney dialysate had no effect on the survival of the mice. After the fractionation of porcine spleen dialysate on Sephadex G-10 column, a significant activity was found in two fractions, II and IX. When active fractions were given together (II + IX) i.p. three days prior to the infection with listeria organisms, the survival of mice increased significantly, whereas no effect was seen when the fractions were given i.v. and the bacteria i.p. Also the treatment with active fractions increased significantly the phagocytic capacity of peritoneal macrophages. Taken together, our results suggest that the Listeria protective substances seem to operate via monocyte activation.

Animals↗
PubMed1985

Cellular immunity in acne vulgaris during transfer factor treatment.

The effect of treatment with human dialyzable transfer factor was investigated on acne vulgaris patients in a double-blind study. About 1/3 of the patients improved clinically during the study period but there was no correlation between clinical improvement and transfer factor treatment. Prior to treatment parameters of cell-mediated immunity were significantly altered in the patients. These alterations normalized during the study in all patients irrespective of transfer factor treatment, possibly due to the immunostimulatory effect of repeated skin testing. The present results support previous findings that acne patients have slightly altered cell-mediated immunity, but the results further suggest that abnormalities are not significant in the pathogenesis of acne vulgaris.

Acne Vulgaris↗
PubMed1980

Polyclonal activation of human lymphocytes by bacteria.

The proliferative response of human unseparated lymphocytes, T cells, and B cells to various bacterial strains was investigated. All the bacteria tested induced a proliferative response in unseparated lymphocytes and B cells. T cells were stimulated only after reconstitution with monocytes. Stimulation of umbilical cord blood lymphocytes suggests that the response is polyclonal. We interpret these and previous data as an indication of a common mechanism of resistance against infectious diseases.

B-Lymphocytes↗
PubMed1980

Evaluation of delayed type immune reactivity in patients with acne vulgaris.

The delayed-type immune reactivities of 39 patients suffering from moderate to severe papulopustular or nodulo-cystic forms of Acne vulgaris were compared with healthy acne-free controls. In vivo reactivity was assessed by skin testing with four common recall antigens. In vitro the afferent arm of the immune system was assayed by antigen and mitogen simulated lymphocyte transformation and the efferent arm by granulocyte random migration and by granulocyte responsiveness to a standard migration inhibitory lymphokine preparation. Spontaneous lymphocyte transformations were also evaluated. In acne patients the skin test reactivities were in general only slightly decreased. Their lymphocytes showed relatively normal responses to mitogen stimulation, but antigen responsiveness was significantly diminished. Furthermore the patients' lymphocytes showed increased spontaneous transformation. All these changes correlated, to some extent, with the severity of the disease. The granulocytes of acne patients showed increased random migration, of borderline significance, but the granulocyte responses to the lymphokine preparation were completely normal. The results suggest that immunologic abnormalities are mild and probably secondary to the inflammatory process.

Acne Vulgaris↗
PubMed1978

Spontaneous lymphokine production by human B lymphocytes.

When human blood lymphocytes are cultured in vitro without any intended stimulus, they produce activities in the supernatant resembling lymphokine. This phenomenon was further investigated in the present study, where it has been demonstrated by physicochemical characterization and inhibition experiments that leukocyte migration inhibitory activity in the supernatants is due to leukocyte inhibitory factor (LIF). When T and B lymphocytes were purified by carbonyl iron and SRBC-rosette sedimentation, only B cells produced LIF and leukocyte chemotactic lymphokine(s) in subsequent cultures. B cells elaborated lymphokines without the help of T cells. the need for co-operation of monocytes was also unlikely. T cells were inactive even when reconstituted with monocytes and platelets.

B-Lymphocytes↗
PubMed1978

Bacteria induce lymphokine synthesis polyclonally in human B lymphocytes.

We have studied the ability of various bacteria to stimulate human lymphocytes to produce leukocyte migration inhibitory factor (LIF). Mononuclear cells from adult and cord blood as well as purified T and B lymphocytes were stimulated with killed bacteria. The culture supernatants were tested for the presence of LIF by the agarose migration method. All nine bacterial strains tested activated unseparated mononuclear cells and B lymphocytes but not T cells to produce LIF. LIF was also present in cord blood cell cultures suggesting that the stimulation of lymphocytes was polyclonal rather than antigenic. Therefore, we propose that one of the physiologic functions of B lymphocyte lymphokines might be to form part of the nonspecific defense mechanisms against microbial invasion.

B-Lymphocytes↗