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Biomedical subjects

M Kubin

Publications and source records attributed to M Kubin.

At least 55 records · Page 3Linked to original sources
PubMed1994

Cooperation of natural killer cell stimulatory factor/interleukin-12 with other stimuli in the induction of cytokines and cytotoxic cell-associated molecules in human T and NK cells.

The ability of natural killer cell stimulatory factor/interleukin-12 (IL-12) to induce cytokines other than IFN-gamma from both T and NK cells was studied. Both the direct effect of IL-12 and the cooperation between IL-12 and other cytokine inducers such as IL-2, phorbol diesters, and receptor antibodies were evaluated. It was found that IL-12 induces mRNA accumulation and production of GM-CSF and TNF-alpha from both T and NK cells and, as tested on NK cells only, induces M-CSF mRNA accumulation. Compared with cytokine inducers, IL-12 ability to induce IFN-gamma production was severalfold higher than its ability to induce GM-CSF or TNF-alpha. Likewise, the synergistic effect of IL-12 with the other stimuli to induce IFN-gamma was stronger than that observed in the case of GM-CSF or TNF-alpha. The IL-12-mediated enhancement of NK cytotoxicity is accompanied by an increased accumulation of mRNA for at least two genes encoding cytotoxic cell granule-associated proteins, the serine esterase granzyme B and the pore-forming protein perforin. IL-12 induction of perforin mRNA accumulation was not synergistic with either IL-2 or anti-CD16 stimulation, whereas granzyme B mRNA accumulation, induced by IL-2 or anti-CD16 stimulation, was slightly potentiated by IL-12. Thus, although IFN-gamma production is probably one of the most physiologically relevant effects of IL-12, induction of other cytokines by IL-12 in the presence of other inflammatory or immune stimuli may have a role in the in vivo functions of IL-12. The observation that both the IL-12-mediated enhancement of NK cell-mediated cytotoxicity and the increased expression of genes encoding cytotoxic cell granule-associated proteins were not cooperative with the effect of other NK cell activators suggests that the effect of IL-12 on cytotoxic cells is in part independent from that of other stimuli regulating the functions of these cells.

CD3 Complex↗
PubMed1993

Interleukin 10 (IL-10) inhibits human lymphocyte interferon gamma-production by suppressing natural killer cell stimulatory factor/IL-12 synthesis in accessory cells.

Natural killer cell stimulatory factor or interleukin 12 (NKSF/IL-12) is a heterodimeric cytokine produced by monocytes/macrophages, B cells, and possibly other accessory cell types primarily in response to bacteria or bacterial products. NKSF/IL-12 mediates pleiomorphic biological activity on T and NK cells and, alone or in synergy with other inducers, is a powerful stimulator of interferon gamma (IFN-gamma) production. IL-10 is a potent inhibitor of monocyte-macrophage activation, that inhibits production of tumor necrosis factor alpha (TNF-alpha), IL-1 and also IFN-gamma from lymphocytes acting at the level of accessory cells. Because TNF-alpha and IL-1 are not efficient inducers of IFN-gamma, the mechanism by which IL-10 inhibits IFN-gamma production is not clear. In this paper, we show that IL-10 is a potent inhibitor of NKSF/IL-12 production from human peripheral blood mononuclear cells activated with Staphylococcus aureus or lipopolysaccharide (LPS). Both the production of the free NKSF/IL-12 p40 chain and the biologically active p70 heterodimer are blocked by IL-10. NKSF/IL-12 p40 chain mRNA accumulation is strongly induced by S. aureus or LPS and downregulated by IL-10, whereas the p35 mRNA is constitutively expressed and only minimally regulated by S. aureus, LPS, or IL-10. Although IL-10 is able to block the production of NKSF/IL-12, a powerful inducer of IFN-gamma both in vitro and in vivo, the mechanism of inhibition of IFN-gamma by IL-10 cannot be explained only on the basis of inhibition of NKSF/IL-12 because IL-10 can partially inhibit IFN-gamma production induced by NKSF/IL-12, and also, the IFN-gamma production in response to various stimuli in the presence of neutralizing antibodies to NKSF/IL-12. Our findings that antibodies against NKSF/IL-12, TNF-alpha, or IL-1 beta can significantly inhibit IFN-gamma production in response to various stimuli and that NKSF/IL-12 and IL-1 beta can overcome the IL-10-mediated inhibition of IFN-gamma, suggest that IL-10 inhibition of IFN-gamma production is primarily due to its blocking production from accessory cells of the IFN-gamma-inducer NKSF/IL-12, as well as the costimulating molecule IL-1 beta.

Antigen-Presenting Cells↗
PubMed1993

Cytokine cross-talk between phagocytic cells and lymphocytes: relevance for differentiation/activation of phagocytic cells and regulation of adaptive immunity.

Cytokines represent one of the most important elements in the communication among different cell types. They play an increasingly better understood role in the communication among hematopoietic cells and in particular in the reciprocal regulation of effector cell types of innate or natural resistance (phagocytic cells and Natural Killer (NK) cells) and those of adaptive immunity (T and B lymphocytes). Lymphocytes produce several cytokines with either stimulatory (e.g., colony stimulatory factor) or suppressive (e.g., tumor necrosis factors and interferons) effects on proliferation of early hematopoietic cells. Many of these cytokines, alone or acting in synergistic combinations, also have a differentiation-inducing ability on immature myeloid cells and act as powerful potentiators of the cellular functions of terminally differentiated phagocytic cells. The communication between lymphocytes and phagocytic cells is not unidirectional, as phagocytic cells produce factors that regulate lymphocyte activation. In addition to their role as antigen presenting cells expressing costimulatory accessory molecules and secreting cytokines (e.g., IL-1, IL-6, TNF), phagocytic cells have been recently shown to produce Natural Killer cell Stimulatory Factor (NKSF/IL-12). IL-12 is a heterodimeric cytokine with important modulatory functions on cytotoxicity of NK and T cells, lymphocyte proliferation, lymphokine production, and development of T helper cell subsets. These communications between phagocytic cells and lymphocytes are further regulated by negative and positive feedback mechanisms that contribute to maintain the homeostasis of the system in physiologic conditions and to govern the changes in this equilibrium needed for the response to infectious or other foreign agents.

Animals↗
PubMed1993

Serovar determination and molecular taxonomic correlation in Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum: a cooperative study of the International Working Group on Mycobacterial Taxonomy.

A cooperative study was conducted by the International Working Group on Mycobacterial Taxonomy to correlate the agglutination serovar designations of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum strains with the species ascriptions of these organisms according to molecular criteria and cultural properties and to assess the reproducibility of serovar determinations for a set of 63 reference strains of these species. Among the molecular criteria, the level of agreement between results obtained with nucleic acid probes and T-catalase serology results was 94% for strains of M. avium and M. intracellulare. Nucleic acid probes were not available for M. scrofulaceum, but none of the 10 strains ascribed to this species on the basis of catalase serology data reacted with a nucleic acid probe for M. avium or M. intracellulare. Ascription to a species on the basis of mycolic acid high-performance liquid chromatography patterns was in agreement with catalase serology results in 86% of the cases examined. Most strains belonging to serovars 1 through 6 and 8 through 11 were identified by molecular criteria as M. avium, most strains belonging to serovars 7, 12 through 20, 23, and 25 were identified as M. intracellulare, and most strains belonging to serovars 41 through 43 were identified as M. scrofulaceum, in agreement with common current practice. Evidence for assigning serovar 27 to M. scrofulaceum was obtained. However, two strains of a given serovar may, on occasion, be placed in different species. The dominant species assignments for strains belonging to serovars 21, 24, 26, and 28 remain unresolved.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination Tests↗
PubMed1992

Production of natural killer cell stimulatory factor (interleukin 12) by peripheral blood mononuclear cells.

Natural killer cell stimulatory factor (NKSF), or interleukin 12 (IL-12), is a 70-kD heterodimeric cytokine composed of two covalently linked chains, p40 and p35. NKSF/IL-12 has multiple effects on T and NK cells and was originally identified and purified from the supernatant fluid of Epstein-Barr virus (EBV)-transformed human B lymphoblastoid cell lines. We have produced a panel of monoclonal antibodies against both chains of NKSF/IL-12. Some of these antibodies have neutralizing activity, and several combinations of them have been used to establish sensitive radioimmunoassays detecting the free p40 chain, the free p35 chain, or the p70 heterodimer. Using these reagents, we have determined that most EBV-transformed human B lymphoblastoid cell lines constitutively produce low levels of the p70 heterodimer and an excess of the free p40 chain, whereas Burkitt lymphoma-derived, T, myeloid, and many solid tumor-derived cell lines produce neither. Production of both p40 and p70 is increased several-fold upon stimulation of the EBV-transformed cell lines with phorbol diesters. The ability of supernatant fluids from unstimulated and phorbol diester-stimulated cell lines to induce interferon gamma (IFN-gamma) production from T and NK cells, one of the effects of NKSF/IL-12, parallels the levels of production of the p70 heterodimer, known to be the biologically active form of NKSF/IL-12. Staphylococcus aureus Cowan I strain (SAC) and other stimuli induce accumulation of p40 mRNA and production of both p40 and p70 by peripheral blood mononuclear cells (PBMC). The producer cells appear to include both adherent cells and nonadherent lymphocytes, possibly B cells. The supernatant fluids from SAC-stimulated PBMC mediate the typical functions of NKSF/IL-12 (i.e., IFN-gamma induction, mitogenic effects on T/NK blasts, enhancement of NK cell cytotoxicity) at concentrations of p70 similar to those at which recombinant NKSF/IL-12 mediates the same functions. Moreover, these activities are significantly inhibited by anti-NKSF/IL-12 antibodies. The neutralizing anti-NKSF/IL-12 antibodies also inhibit 85% of the IFN-gamma production in response to SAC, an NKSF/IL-12 inducer, and approximately 50% of the IFN-gamma production in response to non-NKSF/IL-12-inducers such as IL-2, phytohemagglutinin, and anti-CD3 antibodies. These results indicate that induced or constitutively produced NKSF/IL-12 has a major role in facilitating IFN-gamma production by peripheral blood lymphocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Induction of expression of genes encoding components of the respiratory burst oxidase during differentiation of human myeloid cell lines induced by tumor necrosis factor and gamma-interferon.

In HL-60 and ML-3 human myeloid cell lines, gamma-interferon (IFN-gamma) and/or tumor necrosis factor (TNF) induce synergistic accumulation of transcripts of the genes encoding the heavy chain (gp91-phox) of cytochrome b558 and the cytosolic factors p47-phox and p67-phox, components of the superoxide-generating NADPH oxidase system. The accumulation of transcripts for gp91-phox and p47-phox, as quantitated at the single-cell level by in situ hybridization, is extremely heterogeneous; however, when the cells are stimulated by IFN-gamma and TNF together, most or all the cells in the induced cultures express higher accumulation of gp91-phox and p47-phox transcripts than cells from uninduced culture. In situ hybridization was performed on cellular subsets separated by fluorescence-activated cell sorting on the basis of surface expression of differentiation antigens or respiratory burst activity. The accumulation of gp91-phox and p47-phox transcripts correlated positively with the expression of the CD14 and CD11b antigens, two markers expressed on mature myelomonocytic cells. Similarly, accumulation of the two transcripts correlated with respiratory burst activity in cells separated by fluorescence-activated cell sorting after being loaded with dichlorofluorescein diacetate and stimulated with 12-O-tetradecanoylphorbol-13-acetate. These results suggest that all the cells in the culture are induced to differentiate by TNF and IFN-gamma but that at the time of analysis there is heterogeneity in the level of differentiation and a proportion of cells is present that shows more mature characteristics with a coordinate expression of the various differentiation markers and functions.

Blotting, Northern↗
PubMed1992

Natural killer cell stimulatory factor (NKSF) or interleukin-12 is a key regulator of immune response and inflammation.

Natural Killer cell Stimulatory Factor (NKSF) or interleukin-12 (IL-12) is a heterodimeric cytokine of 70 kDa formed by a heavy chain of 40 kDa (p40) and a light chain of 35 kDa (p35). Although it was originally identified and purified from the supernatant of Epstein-Barr virus-transformed B cell lines, it has been shown that among peripheral blood cells NKSF/IL-12 is predominantly produced by monocytes, with lower production by B cells and other accessory cells. The most powerful inducers of NKSF/IL-12 production are bacteria, bacterial products and parasites. In addition to the biologically active p70 heterodimer, the cells producing NKSF/IL-12 also secrete a large excess of monomeric p40, a molecule with no demonstrable biological activity. NKSF/IL-12 is active on T lymphocytes and NK cells on which it induces production of lymphokines, enhancement of cytotoxic activity and mitogenic effects. NKSF/IL-12 induces T and NK cells to produce IFN-gamma and synergizes with other IFN-gamma inducers in this effect. In vitro, and probably in vivo, NKSF/IL-12 is required for optimal IFN-gamma production. When human lymphocytes are stimulated with antigens in vitro, addition of exogenous NKSF/IL-12 to the culture induces differentiation of T helper type 1 (Th1) cells, whereas neutralization of endogenous NKSF/IL-12 with antibodies favors differentiation of Th2 cells. IFN-gamma, a product of Th1 cells, enhances NKSF/IL-12 production by mononuclear cells, whereas IL-10 and IL-4, products of Th2 cells, efficiently inhibit it. Therefore, NKSF/IL-12 appears to be an important inducer of Th1 responses produced by accessory cells during early antigenic stimulation and its production is regulated by a positive feedback mechanism mediated by Th1 cells through IFN-gamma and a negative one by Th2 cells through IL-10 and IL-4. The balance of IL-12 production versus IL-10 and IL-4 production early during an immune response might therefore be instrumental in determining Th1-type versus Th2-type immune responses. Because of this potential role of IL-12 during immune responses, our results demonstrating the impaired ability of HIV seropositive patients to produce NKSF/IL-12 in response to bacterial stimulation suggest that this defect in NKSF/IL-12 production might be a factor contributing to their immune depression.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Development of an enzyme immunoassay for the serodiagnostic of tuberculosis and mycobacterioses.

An enzyme-linked immunosorbent assay (ELISA) test has been developed for the serodiagnosis of mycobacterioses. The test is based on an interspecific antigen, antigen 60 (A60). This antigen belongs to the group of thermostable macromolecular antigens and is the principal constituent of tuberculin RT 23. A60 is composed of proteins, polysaccharides and lipids in a ratio that varies with the growth cycle of the mycobacterium. The test detects antibodies against mycobacteria and is most effective in cases of active infections. We found that the best way to cope with the day-to-day variations in the results obtained was to transform the absorbance values into arbitrary IgG units. The variations observed with IgM antisera were, however, too great to allow more than a qualitative test. Healthy individuals are negative in the IgG and IgM tests and tuberculous patients are usually positive in the IgG test. The presence of IgM antibodies was only rarely observed. For IgG antibodies, the best discriminative power at a 1:100 dilution of the analyzed sera seemed to lie at 125 sero-units. It was found that some sera originating from clinically documented tuberculous cases responded in a poor way in this test.

Animals↗
PubMed1984

[2 cases of probable interhuman transmission of Mycobacterium bovis].

Transmission of M. bovis infection from a 36 year old father, a veterinary assistant, with cavitary lung tuberculosis and repeated demonstration of M. bovis in sputum to his 11 year old daughter is described. The infection manifested itself by a postinfectional allergic tuberculin reaction which was treated preventively with Isoniazid for 6 months. After 10 months a pulmonary primary complex developed with cavitary disintegration and repeated excretion of M. bovis in sputum. In the second case the source of infection was a 56 year old cattle attendant with cavitary lung tuberculosis and repeated excretion of M. bovis. During repeated contacts he infected his 44 year old friend, a bricklayer, whose resistance was reduced due to anemia and liver impairment. His findings showed cavitary lung tuberculosis in the middle lung field. In this case, too, M. bovis in the sputum was repeatedly demonstrated.

Adult↗
PubMed1980

Phage typing of Mycobacterium kansasii.

An improved phage typing scheme of M. kansasii is presented. Ultrasonic treatment of the bacterial suspensions was successfully used in order to obtain homogeneous bacterial growth and to improve the reproducibility of the typing. By means of 9 phages 14 lysis patterns (phage types) could be distinguished. The phage typing was applied to 450 strains of Dutch, British and Czechoslovakian origin. The epidemiological relationships between environmental and clinical isolates of M. kansasii among the strains of Dutch and Czechoslovakian origin was confirmed by the results of phage typing.

Bacteriophage Typing↗
PubMed1979

Comparison of auramine-rhodamine B and acridine orange for staining of acid-fast bacteria.

In cooperation of 6 laboratories in Czechoslovakia and in the GDR, the efficiency of auramine-rhodamine B (AR) and acridine orange (AO) (short-time method) for staining of acid-fast bacilli was compared. Whereas a former comparison of AR and AO (original method) pointed out the superiority of AR, the investigation of both methods used as short-time procedures showed significantly more acid-fast rods after using AO. The number of "false positive" results was somewhat higher on AR staining. However the results depend not only on the method used but also on the procedure of staining and the optical equipment, and they are essentially influenced by the experience and proficiency of the microscopist. Taking into account the results of both studies both auramine-rhodamine B and acridine orange can be proposed for the staining of slides for microscopical detection of acid-fast rods. In case of AO, the short-time method is superior to the original long-time procedure.

Acridine Orange↗
PubMed1977

[Tonographic and tonometric aqueous humor outflow tests after trabeculotomy (author's transl)].

In 10 eyes which trabeculotomy was performed because of primary open angle glaucoma preoperatively, 1 to 3 months and 12 months postoperatively the diurnal curves and tonographic results were compared. The i.o. pressure was reduced in all eyes. The ocular rigidity was decreased from 0.0206 +/- 0.0019 (s.d.) preoperatively to 0.0164 +/- 0.0015 after 1 to 3 months and to 0.0168 +/- 0.0017 after 12 months. Regarding the individual change of ocular rigidity, the outflow facility was improved on an average of from 0.13 +/- 0.02 preoperatively to 0.37 +/- 0.10 or 0.20 +/- 0.03 units postoperatively. This means a reduction of the resistance to aqueous outflow from 10.62 +/- 1.89 to 3.88 +/- 0.57 or 5.77 +/- 0.77 units. The differences are statistically significant. If the changings of ocular rigidity are not regarded there is no significant improvement of the conditions of aqueous humor outflow.

Aged↗