Biomedical subjects

B Chorváth

Publications and source records attributed to B Chorváth.

At least 55 records · Page 3Linked to original sources

PubMed1991

Fluorescent double labeling of normal and malignant hematopoietic cells by monoclonal antibodies (FITC) and anthracycline cytostatic drug (Daunomycin): a cytometric technique for analysis of drug uptake in hematopoietic cell subpopulations.

A technique of simultaneous double labeling of normal and neoplastic hematopoietic cells with FITC-conjugated monoclonal antibodies directed to selectively expressed hematopoietic cell surface antigens (green fluorescence) and the anthracycline cytostatic drug (Daunomycin, red fluorescence) was described. Flow cytometric analysis of double labeled cells permitted anthracycline cell content determination in peripheral blood lymphocytes, granulocytes, monocytes from healthy donors, T- (MOLT-4), non-T, non-B (REH) and myelomonocytic (U-937) leukemic cell lines. After mixing peripheral blood lymphocytes from healthy individuals with cultured leukemic cells labeled on a restrictively expressed hematopoietic cell differentiation antigen (CALLA-CD10-, MHC class II-DR-antigen, a myelomonocytic differentiation antigen) detected by corresponding monoclonal antibodies (DGH-10-1-A9,Bra30, BraC8), the described technique allowed separate measurements of anthracycline content in leukemic cells vs. peripheral blood lymphocytes from healthy donors. Potential diagnostic aspects and research utilization of this technique are discussed.

Antibodies, Monoclonal↗

PubMed1991

Human monoblastoid cell line U-937 cultured in protein-free medium: immunophenotype, cytochemical and biochemical markers.

Human monoblastoid cell line U-937 was adapted to grow in protein-free (protein-free hybridoma--PFH) medium and cloned by limiting dilution. Resulting cell subline (U-937/PF) cultured in protein-free medium was characterized by immunological, cytochemical and biochemical techniques. There were no major differences in immunophenotype (determined by FACS analysis with monoclonal antibodies directed to HLA and CD antigens) and cytochemical markers between the U-937/PF cells cultured in protein-free cell culture medium and parental U-937 cell cultured in serum-supplemented medium. Maximal cell density was slightly decreased in protein-free culture as compared to the parental cell line in FCS-supplemented medium. Cell viability and cell DNA histograms (determined by propidium iodide cytofluorimetry) showed no major differences between parental U-937 and U-937/PF cells. Phorbol ester (TPA)-induction of differentiation-associated cell markers resulted in a proliferation arrest and accumulation of G0/G1 cells in both sublines. All-trans retinoic acid and, to a lesser extent, TPA-stimulated NBT reduction was higher in parental U-937 cells cultured in serum-supplemented medium as compared to U-937/PF cells. Quantitative differences in the expression and inducibility of some cytochemical markers (beta-glucuronidase, chloroacetate esterase) were found between both examined sublines. Described U-937/PF subline cultured in a protein-free cell culture medium (PFH) appeared as a potential tool for studies of in vitro inducing agents and serum components with differentiation promoting (or inhibiting) activities.

Acid Phosphatase↗

PubMed1990

Modulation of CALLA (CD10) antigen on cultured ALL (REH) cells: effect of various modulators.

Phorbol ester (TPA)-induced down-regulation of the common ALL (CALLA) antigen was studied by continuous flow immunocytometry with the aid of several CD10 monoclonal antibodies, including a new CD10 monoclonal antibody (DGH-10-1-A9), shown to be of IgG1 isotype, recognizing a 100 kDa cell surface protein and effectively inhibited by a series of reference CD10 monoclonal antibodies. The TPA-induced down-regulation of CALLA on REH cells was demonstrated with the aid of the following CD10 monoclonal antibodies: J-5, VIL-A1 and DGH-10-1-A9. No major modulations in cell surface expression of CALLA on REH cells were observed after induction with 1,25-(OH)2 vitamin D3, retinoic acid, recombinant interferon (IFN) alpha 2a and recombinant interleukin 2.

Antibodies, Monoclonal↗

PubMed1990

Biochemical and immunological phenotype alterations in human monoblastoid cell line U-937 induced by physiological (interferon-alpha, retinoic acid) and nonphysiological (phorbol ester) inducers.

Human monoblastoid cell line U-937 was induced by recombinant or leukocyte human interferon-alpha, retinoic acid, by their combination, or by 12-0-tetradecanoyl-phorbol-13-acetate (TPA), to express some differentiation-associated markers and characteristics. Induced biochemical alterations were studied with the aid of two-dimensional electrophoretic analysis (isoelectrofocusing/SDS-PAGE) of 125I-lactoperoxidase radioiodinated cell surface proteins, 35S-methionine metabolically radiolabeled cell proteins and 32P orthophosphate radiolabeled cell phosphoproteins. Alteration of immunophenotype markers was studied by continuous flow immunocytofluorometry with a panel of monoclonal antibodies directed to leukocyte antigens, cell proliferation, DNA, RNA, and protein synthesis by radioactive precursor incorporation techniques. Furthermore, cytochemical markers, cell adherence and nitroblue tetrazolium (NBT) reduction were utilized to follow the induction of differentiation-associated characteristics. Differential alterations of some immunophenotype markers induced by diverse inducers were observed. Major induced alterations included down-regulation of CD4 (induced by TPA, and to a lesser extent by IFN-alpha), TPA-induced decrease of cell surface expression of transferrin receptor (unmodified by IFN-alpha) and IFN-alpha induced increase of antigen density (fluorescence intensity) of MHC class I antigen. Marked retinoic acid and interferon-alpha induced increase in membrane expression of antigen(s) detected by monoclonal antibodies BraC6 and BraC8, elicited with healthy donor's granulocytes, was also observed.

Antigens, Surface↗

PubMed1989

Isoforms of leukocyte common antigen (CD45) on human neoplastic hematopoietic cell lines.

Leukocyte common antigen (LCA) isoform expression patterns were examined on different human hematopoietic cells and cell lines with the aid of the immunoblotting technique utilizing two anti-LCA monoclonal antibodies elicited by an ALL cell line and able to detect four isoforms (180, 195, 205 and 220 kDa) of LCA on peripheral blood lymphocytes from healthy donors and some neoplastic hematopoietic cell lines. Fourteen leukemia/lymphoma cell lines of different origin and immunophenotype, as well as three nonhematopoietic human tumor cell lines were examined by this technique. Human hematopoietic cell lines expressed two to four different polypeptide chains (180, 195, 205 and 220 kDa). Non-T, non-B cell lines, some B-cell lines and monocyte lymphoma cell line U 937 predominantly expressed higher molecular weight isoforms. In myeloid leukemia cell lines examined the expression of lower molecular weight isoform(s) predominated. Individual variability in LCA isoform patterns on cell lines precluded the strict correlation between these patterns and immunophenotype of the examined cell lines.

Antibodies, Monoclonal↗

PubMed1989

Monoclonal antibodies (series Bra-) of broad (non-lineage) or restricted (myelomonocytic) reactivities elicited with granulocytes or K 562 cells.

A series of monoclonal antibodies was obtained by hybridoma technology after immunization with granulocytes from healthy donors or K 562 immature erythroid-myeloid leukemia cells. Three different types of reactivities with examined hematopoietic-, nonhematopoietic cells and cell lines were observed by microscopic immunofluorescence, immunocytofluorometry and enzyme-linked immunoassay (ELISA), as follows: (i) broad, non-lineage type of two monoclonal antibodies (Bra10G and Bra7F1) with examined hematopoietic and nonhematopoietic human neoplastic cell lines, (ii) non-lineage type of reactivity restricted to hematopoietic cell lines, and (iii) restricted (myelomonocytic) pattern of binding to myeloid cell lines and healthy donors' granulocytes (monoclonal antibodies Bra4F1, BraC8 and Bra1F2). Monoclonal antibodies Bra10G and BraC6 were shown to immunoprecipitate specifically a heterodimeric two-chain cell surface protein p200,95 from cell lysates of lactoperoxidase radioiodinated U 937 cells with recognized epitope localized on the heavy chain (as shown by immunoblotting experiments). Antibodies with restricted myelomonocytic type of reactivity exhibited minor quantitative differences in their microscopic immunofluorescence and immunocytofluorometric patterns of reactivities with examined myeloid leukemia cell lines (K 562, HL 60, U 937) and healthy donors' granulocytes. The monoclonal antibody Bra4F1 was defined by the 4th International Workshop on Leukocyte Differentiation Antigens as CD15 (with typical selective reactivity towards myelomonocytic leukemia cells and cell lines as well as healthy donors' granulocytes) recognizing the X-hapten carbohydrate antigenic determinant.

Antibodies, Monoclonal↗

PubMed1989

Study of metabolism and growth limitation of human leukemia cell lines.

The relationship between proliferation and metabolism of four leukemia cell lines (BALL-1, JOK-1, Jurkat, and MOLT-4) in batch culture was studied. The maximum cell density (1.5-2.3 x 10(6) cells/ml) without change of medium was observed on days 6-8 of cultivation. At the same time, the original concentration of glucose in the medium (10 mmol/l) fell to 3.5-4 mmol/l. While BALL-1 and MOLT-4 cells, on day 4 of cultivation, converted 82% of glucose into lactate, on day 7 this value was 50%, or there was no lactate production (MOLT-4), respectively. On the other hand, the values of the coefficient of glycolysis showed that Jurkat and JOK cells converted also other compounds into lactate. Part of the utilized glutamine was employed by all four cell lines: 1. as a precursor of glutamic acid, and 2. as a source of energy. BALL-1 and JOK-1 cells converted part of arginine into ornithine. At the time when the proliferation of the cells ceased, the level of ammonia reached a toxic concentration of 2.0-3.6 mmol/l. Since these cell lines utilized only a part of carbon and nitrogen sources in the medium, it was suggested that the final cell density was limited by a growth inhibitor (i.e. ammonia) and not by a lack of nutrients.

Amino Acids↗

PubMed1988

Characterization of a new murine monoclonal antibody against human DP antigens.

Murine Hybridoma cell line BraFB6 was prepared producing monoclonal antibody reactive with an antigen identified as DP. This identification is based on the results of immunoprecipitation from radiolabeled cell lysates, competitive binding-inhibition assay with a reference anti-DP antibody B7/21, sequential immunoprecipitation and specific binding to the purified DP glycoprotein. In addition to this anti-DP monoclonal antibody, two anti-DR and two anti-DR +DP monoclonals were obtained.

Animals↗

PubMed1988

Immunocytometric characteristics of a monoclonal antibody (Bra55) recognizing the leukocyte common antigen (LCA).

The immunofluorescence cytofluorometric reactivity pattern of monoclonal antibody Bra55 (IgG1) elicited with a non-T, non-B ALL cell line (REH), with a panel of human neoplastic hemopoietic cell lines (including non-T, non-B, T and myeloid leukemia cell lines) and with isolated peripheral blood lymphocytes, monocytes and granulocytes from healthy donors corresponded to the previously described microscopic immunofluorescence, ELISA, immunoprecipitation and immunocytochemic data indicating that this monoclonal antibody recognizes a 170-220 kDa cell surface glycoprotein (leukocyte common antigen) expressed selectively on hemopoietic cells. The purified, FITC-conjugated Bra55 monoclonal antibody was effectively inhibited in its binding to the surface of LCA-positive cells by reference anti-LCA monoclonal antibodies; no inhibition of this activity by LCA-unrelated monoclonal antibodies (such as anti-MHC class I and class II antibodies) was observed. These data confirm the previously reported hemopoietic cell specificity (anti-LCA, CD45) of the Bra55 monoclonal antibody.

Antibodies, Monoclonal↗

PubMed1988

Monoclonal antibody directed to MHC class I antigen (Bra23/9): characterization and utilization for study of antigen expression in differentiation of U 937 cell line.

The monoclonal antibody Bra23/9 (IgG2a) elicited by a non-T, non-B ALL cell line (REH), reacted in microscopic immunofluorescence, enzyme-linked immunoassay (ELISA), complement-dependent cytotoxicity tests and immunocytofluorometric measurements with hemopoietic cell lines and peripheral blood lymphocytes, monocytes and granulocytes from healthy donors in a pattern characteristic for MHC class I antigens. Immunoprecipitation of lactoperoxidase radioiodinated cell surface proteins and surface sialoglycoproteins radiolabeled by sodium metaperiodate/tritiated sodium borohydride technique confirmed the structure gp44,p12 (consisting of a 44 kDa glycopeptide linked with a nonglycosylated 12 kDa peptide) typical for MHC class I antigen(s) as a structure recognized by the Bra23/9 monoclonal antibody. The increase of MHC class I antigen density (immunofluorescence intensity) induced by a phorbol ester (TPA) in monoblast U 937 lymphoma cell line was observed by immunocytofluorometry as a predominant tendency in several TPA-induction experiments, where a certain variability among individual experiments in TPA-induced MHC class I antigen alterations was observed.

Antibodies, Monoclonal↗

PubMed1987

Human neoplastic cell line distribution, immunoprecipitation and immunohistopathological study of a gp200 cell surface glycoprotein (LCA) detected by a monoclonal antibody elicited with an ALL cell line.

The antigen recognized by a newly produced monoclonal antibody (bra55; IgG1) elicited by the non-T, non-B acute lymphoblastic leukemia cell line REH 6, was expressed on all examined hemopoietic neoplastic cell lines (including non-T, non-B, T, B and myeloid leukemia cell lines), but not on examined nonhemopoietic human tumor cell lines (such as carcinoma, sarcoma, melanoma and neuroblastoma cell lines), as demonstrated by indirect immunofluorescence and enzyme-linked immunoassay. Specific immunoprecipitation of 125I-lacto-peroxidase radioiodinated cell surface proteins and sodium metaperiodate/tritiated sodium borohydride 3H-radiolabeled cell surface sialoglycoproteins followed by electrophoretic analysis (SDS-PAGE) demonstrated that the immunoprecipitated antigen is a cell surface 200 kDa sialoglycoprotein (on the non-T, non-B ALL cell line REH 6), with variation in its electrophoretic mobility (in the Mr range of 170,000-210,000) on different examined cell lines. These properties are characteristic for the leukocyte common antigen (LCA, T200). Immunoperoxidase staining of several normal and malignant tissues, as well as some nonhemopoietic tumor tissues confirmed the type of antigen tissue distribution pattern characteristic for LCA.

Antibodies, Monoclonal↗

PubMed1987

Supplementary characteristics of anti-MHC class II monoclonal antibodies elicited by an ALL cell line: immunofluorescence cytofluorometry, C-dependent cytotoxicity, two-dimensional analysis of antigen.

Monoclonal antibodies directed to MHC class II antigen(s), elicited by a non-T, non-B ALL cell line, were characterized by immunofluorescence flow cytofluorometry and ELISA immunofiltration measurements of their immunoreactivity with selected neoplastic hemopoietic cell lines, determination of their complement-dependent cytotoxic activity against isolated peripheral blood B and T lymphocytes and by two-dimensional electrophoretic analysis (isoelectric focusing, SDS-PAGE) of radiolabeled, immunoprecipitated by these antibodies cell surface antigens. Patterns of these immunological reactivities, as well as two-dimensional radioimmunoprecipitation patterns (acidic heavy chain p35 and basic light chain p30) of antigens recognized by these antibodies confirm their anti-MHC class II specificity. One of these antibodies (braFB6; IgG2b) displayed identical pattern of expression on cell lines and cell types as the typical anti-MHC class II antibodies, but immunoprecipitated only a single chain p30 radioiodinated cell surface protein (with two-dimensional pattern close to the beta-chain of MHC class II DR antigen). These properties indicate the ability of braFB6 monoclonal antibody to recognize a nonpolymorphic determinant of DP-MHC class II antigen.

Antibodies, Monoclonal↗

PubMed1986

Two-dimensional analysis of metabolically and cell surface radiolabeled proteins of some human lymphoid and myeloid leukemia cell lines. I. 35S-methionine labeled, lactoperoxidase radioiodinated and 3H-reductively methylated proteins.

Cell surface and cytoplasmic polypeptides of some human hemopoietic cell lines were radiolabeled by three different techniques: 35S-methionine metabolic radiolabeling, lactoperoxidase catalyzed radioiodination and reductive methylation with formaldehyde and tritiated sodium borohydride. Two-dimensional patterns of 35S-methionine labeled proteins revealed more than 500 separated protein spots with essentially similar general aspects of all examined cell lines, sharing major polypeptides such as those with electrophoretic mobilities of major cytoskeletal proteins. 125I-lactoperoxidase radio-iodinated cell surface protein patterns contained about 30 separated protein macromolecules with some marked differences between lymphoid versus myeloid lines and also between individual cell lines. Two-dimensional patterns of tritiated membrane polypeptides consisted of approximately 200 separated protein spots, some prominent of them appeared with electrophoretic mobilities of major cytoskeletal proteins being common to both 35S-methionine and reductive methylation patterns. Two-dimensional patterns of 35S-methionine labeled and cell surface radioiodinated proteins immunoprecipitated by monoclonal antibodies Bra30 and HL39, recognizing MHC class II antigens, appeared as bimolecular complex of larger acidic and smaller basic chains structurally corresponding to the expected two-dimensional patterns of MHC class II antigens.

Autoradiography↗

PubMed1986

Two-dimensional analysis of metabolically and cell surface radiolabeled proteins of some human lymphoid and myeloid leukemia cell lines. II. Glycosylated and phosphorylated proteins.

Cell surface glycoproteins, radiolabeled by sodium metaperiodate/tritiated borohydride technique and cell phosphoproteins, metabolically radiolabeled by 32P-orthophosphate were analyzed by two-dimensional electrophoretic analysis in some myeloid and lymphoid leukemia cell lines. Some markedly expressed major glycoproteins were predominant in some of cell lines (such as 95k and 100k glycoproteins with marked charge heterogeneity in non-T, non-B acute lymphoblastic leukemia cell lines NALM 6 and NALM 16), but markedly quantitatively reduced in other examined cell line, such as lymphoblastoid cell line UHKT 34/2. 32P-orthophosphate radiolabeled phosphoprotein two-dimensional patterns of examined lymphoid leukemia cell lines were essentially similar, with some minor differences, in examined lymphoid and myeloid leukemia cell lines, such as marked expression of a series of large phosphoproteins in the molecular weight range 80-100k in lymphoid cell lines and almost complete absence of these phosphoproteins on examined myeloid leukemia cell lines. Another configuration of acidic phosphoproteins (30-35k) exhibited individual cell line variability and differences between both individual myeloid leukemia cell lines and between lymphoid and myeloid cel lines examined.

Cell Line↗

PubMed1985

Monoclonal antibodies against MHC class II antigens elicited with a human non-T, non-B acute lymphoblastic leukemia cell line.

A series of seven monoclonal antibodies recognizing cell surface antigens of similar distribution on a panel of leukemia/lymphoma and lymphoblastoid human cell lines was prepared by hybridoma technique after immunization with non-T, non-B acute lymphoblastic leukemia cell line REH. Immune reactivity of these monoclonal antibodies with B-lymphoblastoid and lymphoma cell lines, as well as with non-T, non-B leukemia cell lines but not with T-leukemic and myeloid leukemic cell lines (with the exception of myeloid leukemia cell line KG 1) was demonstrated by indirect immunofluorescence. No reactivity was observed with the examined human non-hemopoietic tumor cell lines, except melanoma cell lines HMB-2 and SK 1477. These antibodies immunoprecipitated a similar cell surface bimolecular glycoprotein complex consisting of two glycosylated chains (gp30, 35), as demonstrated by immunoprecipitation of cell surface 125I-lactoperoxidase radioiodinated, periodate/tritiated borohydride radiolabeled and 35S-methionine metabolically radiolabeled proteins of REH cells. These properties, typical of MHC class II antigens correspond also to immunoperoxidase staining of lymph nodes with some selected antibodies.

Antibodies, Monoclonal↗

PubMed1985

Hemopoietic cell line distribution and immunoprecipitation of cell surface proteins recognized by two newly prepared monoclonal antibodies elicited by a human non-T, non-B leukemia cell line.

Two newly prepared monoclonal antibodies elicited by a human non-T, non-B acute lymphoblastic leukemia cell line REH recognized distinct antigenic specificities characterized by the pattern of their immunofluorescence reactivities with a panel of hemopoietic cell lines and by immunoprecipitation of 125I-lactoperoxidase radioiodinated cell surface proteins, as well as periodate/tritiated borohydride radiolabeled cell surface sialoglycoproteins. Monoclonal antibody anti-p30 (BraFB6; IgG2b) recognized an antigen similar in its distribution to MHC class II antigens and immunoprecipitated a p30 cell surface protein, radiolabeled by lactoperoxidase catalyzed radioiodination. Monoclonal antibody anti-gp95 (BraEA10; IgG3) reacted in immunofluorescence intensively with non-T, non-B, T-leukemia and myeloid leukemia cell lines, less intensively with lymphoblastoid and lymphoma cell lines of B-phenotype and no reactivity was observed with examined non-hemopoietic human tumor cell lines. This antibody immunoprecipitated a lactoperoxidase radioiodinated and periodate/NaB3H4 tritium-radiolabeled cell surface sialoglycoprotein of approximately 95k (gp95) with variability in its apparent molecular weight, related to the origin of cells utilized for radiolabeling and immunoprecipitation.

Antibodies, Monoclonal↗

PubMed1985

A simple technique for cell surface radioactive labeling of human and animal neoplastic cells: reductive methylation with formaldehyde and tritiated borohydride.

Avian sarcoma virus-, or 3,4-benzopyrene-transformed cultured rat cells and human leukemia or lymphoblastoid cell lines were radiolabeled by reductive methylation with formaldehyde and tritiated sodium borohydride--an application of a known technique for radiolabeling of soluble proteins. Optimal conditions for tritium incorporation into cell proteins with the aid of this technique were ascertained. Analysis of cell proteins tritium radiolabeled with the aid of this technique by acrylamide electrophoresis or by two-dimensional electrophoretic analysis allowed to disclose typical transformation-associated alterations in oncovirus-, or chemical carcinogen-transformed cells, as well as cell type-associated protein patterns in examined lymphoid cell lines. An individual protein (class II MHC antigen) radiolabeled by this technique has been identified as bimolecular complex p30,35 by immunoprecipitation with a monoclonal antibody recognizing this antigen; electrophoretic properties of immunoprecipitated antigen were identical to those observed after immunoprecipitation of the same antigen radiolabeled by sodium periodate/tritiated borohydride glycoprotein radiolabeling.

Animals↗

PubMed1985

Studies on the distribution of the antigens detected by some newly prepared monoclonal antibodies in normal hemopoietic and leukemic cells.

A great number of hybridoma clones has been developed in two independent fusions after immunization with cells of a human non-T, non-B REH leukemic cell line, recognizing different differentiation antigens on leukocytes. Only four of these new murine monoclonal hybridoma-derived antibodies (Bra20, Bra30, BraFB6 and BraEA10) have been used in our study for determination of their reactivity spectrum in normal blood cells and fresh lymphoid and non-lymphoid leukemic cells. The resulting reactivity spectra of these four monoclonal antibodies in normal hemopoietic and leukemic cells in indirect immunofluorescence assay are in agreement with supposed Ia-like reactivity for Bra20, Bra30 and Bra FB6 monoclonal antibodies and "common" leukocyte specificity for BraEA10 monoclonal antibody.

Antibodies, Monoclonal↗