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L Mátyus

Publications and source records attributed to L Mátyus.

At least 37 records · Page 2Linked to original sources
PubMed1988

The different effect of alpha and gamma interferons and interleukin 2 on the expression of CD2, CD3, CD4 and CD8 antigens in comparison to histocompatibility antigens of human lymphocytes.

The effects of alpha- and gamma-interferons (IFN-alpha, -gamma) and of interleukin 2 (IL-2) on the expression of certain differentiation antigens were compared with those of major histocompatibility antigens on human lymphocytes. IFN-gamma and IFN-alpha in high doses significantly increased the expression of T11 (CD2) differentiation antigen, but did not affect the expression of T4 (CD4), T8 (CD8), T3 (CD3) and Leu-7 antigens (HNK-1). Both natural and recombinant IFN-alpha and -beta apparently increased the expression of HLA-ABC antigens and of beta-2 microglobulin (beta 2m) after 16 h incubation. The amount of HLA-DR antigen, however, doubled in a few hours following IFN-gamma treatment. IL-2 affected the expression of CD2 and CD8 antigens only marginally, but did not affect that of CD3 and Leu-7; however, it strongly enhanced the expression of HLA-ABC, HLA-DR, and beta 2m antigens.

Antigens, Differentiation↗
PubMed1987

Flow cytometric measurements of fluorescence energy transfer using single laser excitation.

Flow cytometric energy transfer (FCET) measurements between labeled specific sites of cell surface elements (Szöllosi et al., Cytometry, 5:210-216, 1984) have been extended in a simplified form using a flow cytometer equipped with single excitation beam. This versatile and easily applicable method has several advantages over any nonflow cytometric (i.e., spectrofluorimetric) energy transfer measurements on cell surfaces: The labeled ligands can be applied in excess, without washing, thereby enabling the investigation of relatively labile receptor-ligand complexes. Contributions of signals from cell debris, from cell aggregates, or from nonviable cells can be avoided by gating the data collection on the light scatter signal. The heterogeneity of the cell population with respect to the proximity of the labeled binding sites can be studied. In the cases of homologous ligands or of ligands binding to the same molecule but at different epitopes, the determination of fluorescence resonance energy transfer efficiency values can be carried out on a cell-by-cell basis, offering data on intramolecular conformational changes. This modified FCET method enabled us to demonstrate the uniform density of glycoproteins, specific for Con A binding, in the plasma membrane of normal and Gross virus leukemic mouse cells of different sizes. The utility of this procedure has also been demonstrated by using the mean fluorescence intensities of the distribution curves in the calculation of the fluorescence energy transfer efficiency.

Antigens, Surface↗
PubMed1987

Flow cytometric determination of the sperm cell number in diluted bull semen samples by DNA staining method.

Flow cytometric determination of the number of bull sperm cells showed that the number of spermatozoa measured by light scattering may considerably differ from the actual number of sperm cells in the samples, depending on the proportion of contaminating particles, similar in size to sperm cells. No accurate information can be obtained from the sum of live and dead cells distinguished by means of double fluorescence staining, since a part of the sperm cell population is in a transitory state i.e. between the viable and dead states, so it cannot be stained by either dye. The number of spermatozoa in the sample can be determined very accurately if the sample is treated first with Nonidet-P-40 detergent then stained with propidium iodide. With this procedure the DNA content of each cell nucleus can be labeled and, through detecting the fluorescence signals, the actual sperm cell count of the sample can be determined with the accuracy of 95-98%.

Animals↗
PubMed1986

Accessibility of cell surface thiols in human lymphocytes is altered by ionophores or OKT-3 antibody.

The accessibility of cell surface sulfhydryl groups in human peripheral lymphocytes was investigated with 5,5'-dithiobis-(2-nitrobenzoic acid) in the presence and absence of ionophore antibiotics and the monoclonal antibody, OKT-3. Only a few accessible protein thiols have been found on the cells as demonstrated by labeling with a fluorescent non-penetrating thiol-marker, monobromotrimethyl-ammoniobimane and the subsequent gel electrophoretic analysis of the protein pattern. Difference spectrophotometric measurement of thiol-DTNB reaction revealed that ionophores altering the transmembrane potential induced an enhanced cell surface thiol-exposure on the minute time scale. The effect showed a dependence on the external concentration of the cations. The binding of monoclonal antibody, OKT-3, directed against T3 complexes, resulted in a similar, concentration-dependent increase of thiol-accessibility. These data are interpreted as early membrane-effects of ionophores and the specific antibody including changes in the conformational equilibrium or vertical displacements of certain membrane proteins. These events are likely to be coupled to the changes in the transmembrane potential of the lymphocytes.

Anti-Bacterial Agents↗
PubMed1986

Cyclosporin A depolarizes cytoplasmic membrane potential and interacts with Ca2+ ionophores.

Cytoplasmic membrane potential of mouse lymphocytes was determined with flow cytometry and fluorescence spectroscopy using 3,3'-dihexylcarbocyanine iodide (DiOC6(3)). The amount of this lipophilic cation incorporated into the cytoplasmic membrane is dependent upon the transmembrane potential, so the dye is suitable for continuous monitoring of this parameter, under controlled conditions. Membrane potential of the cells was decreased in the presence of cyclosporin A and cyclosporin G in a dose-dependent manner. However, the depolarization caused by Ca2+ ionophores, ionomycin and A23187, was reduced in the presence of cyclosporin A. Electron spin resonance spectroscopy with 5-doxylstearic acid as a probe indicated that cyclosporin A decreased the apparent motional freedom of membrane lipids. These data suggest incorporation of cyclosporin A into the cytoplasmic membrane, causing changes in ion fluxes. The membrane potential change induced by cyclosporin A may have selective biological consequences in certain subpopulations of lymphocytes.

Animals↗
PubMed1985

Subset specificity of lupus antilymphocyte antibodies studied by two-colour microfluorimetry.

Subset specific lymphocytotoxic activity of lupus sera was studied by a combination of selective immunofluorescence labelling and complement-mediated lysis. Most frequently death of B cells was detected. Many of the sera caused lysis of T lymphocytes; selective cytotoxicity against suppressor T cells could be observed less frequently. All the anti-T4, anti-T8 and anti-B lymphocyte antibodies proved to be cold reactive.

Antibody Specificity↗
PubMed1984

A follow-up study of the development of Rauscher erythroleukemia.

Expression of cell membrane antigens recognized by antiserum raised against purified Friend murine leukemia virus (Fr-MuLV) envelope glycoprotein (gp71) and by xenotropic MuLV-coded cell surface antigen (XenCSA) specific antibodies was studied in the course of the development of Rauscher erythroleukemia in the spleen of Balb/c mice. DNA content vs immunofluorescence or light scattering of cells were simultaneously analyzed. At early stages of the disease (4-5 days after infection) the gp71 and XenCSA-related antigen expression is enhanced mainly on S-G2/M-phase cells as compared to the majority of G1-phase cells or to the endogenous background of uninfected cells. Later (around 10 days after infection) an approximately ten-fold increased gp71-related antigen density is reached in every phase of the cell cycle. These data show that the virus-induced transition from resting to proliferating state is coupled to enhanced expression of both helper and defective viral env-gene products in the cell membrane of mitotic and G1-phase cells as well.

Animals↗
PubMed1984

Cellular DNA content of T helper, T suppressor and B lymphocytes in SLE.

The ratio of in vivo activated T helper, T suppressor and B cells in the blood of patients with SLE has been studied through simultaneous subset specific immunofluorescence labelling and the analysis of cellular DNA content with the help of flow fluorimetry. In the active stage of the disease an increase was observed in the proportion of proliferating cells either among the T helper cells or the B cells. Occasionally, however, the rate of proliferation in both subsets grew at the same time. Cases with a high number of activated B cells have proved to be more serious. The percentage of the T suppressor cells in the S-G2-M phase of the cell cycle increased moderately in both the active and the inactive stages of the disease. Our results are also discussed in relation to the pathogenetic mechanism of SLE.

B-Lymphocytes↗
PubMed1984

Flow cytometric analysis of viability of bull sperm cells.

Fluorescein diacetate and propidium iodide double fluorescence labeling of animal sperm cells in combination with 55 degrees C treatment for 15 min was used to monitor the viability and heat tolerance of sperm cells by flow cytometry. The applicability of the elaborated test to detect fertility differences has been shown on sperm samples obtained from bulls of known fertility values. According to preliminary examinations the method seems to be suitable to test the fertility of other male animals, too. The simplicity of the relatively quick procedure may provide a new screening method to qualify male animals before using their semen for large scale artificial insemination.

Animals↗