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Biomedical subjects

A Ziegler

Publications and source records attributed to A Ziegler.

At least 289 records · Page 16Linked to original sources
PubMed1986

Mapping of HLA genes using pulsed-field gradient electrophoresis.

The technique of pulsed-field gradient electrophoresis (PFGE) allows the determination of gene linkage relationships since DNA fragments up to 2 Mb can be separated. PFGE was employed to study linkage of class I, II and III genes belonging to the human major histocompatibility (HLA) complex. The results establish that the class II DO beta and DZ alpha genes are linked with the DP subregion, centromeric to the DQ/DX-DR-C4 chromosomal segment, and allow us to estimate the minimal length of the entire HLA complex.

Chromosome Mapping↗
PubMed1986

Separate ontogeny of two macrophage-like accessory cell populations in the human fetus.

Human macrophage-like accessory cells were analyzed as they emerge in the absence of extrinsic antigens during fetal development. Monoclonal antibodies to monocytes/macrophages were used in combination with antibodies to HLA class II molecules. In the yolk sac and mesenchyme sampled at wk 4 to 6 of fertilization age, cells with dendritic morphology formed two populations distinguishable by phenotypic criteria: type i (majority) carried both macrophage-associated (RFD7+) and monocyte-associated markers (UCHM1+) but no detectable HLA-DR antigen, and type ii (minority) constitutively expressed class II (HLA-DR and -DP) but no RFD7 and UCHM1. The emergence of this heterogeneity preceded the formation of both thymus and bone marrow. During additional development, type i and type ii cells seeded to different microenvironments and underwent some additional phenotypic changes. Cells of type i, the RFD7+ population with high lysosomal (acid phosphatase) activity, were seen in the thymic cortex, marginal zone of lymph nodes, splenic red pulp, and in the midst of erythropoietic activity within the bone marrow. These cells were UCHM1- and class II-. Cells of type ii formed the population of HLA-DR+, RFD7- interdigitating cells, early inhabitants of T cell areas in the developing thymic medulla, lymph nodes, spleen, and tonsil. The Type ii cells that had already settled in their nichès expressed not only HLA-DR and -DP but also HLA-DQ, and another class II antigen identified by the antibody RFD1, which shows the restricted tissue distribution of HLA-DQ, but is governed by genes that are outside of and telomeric to the HLA-DQ region (or HLA-DR). Finally, subpopulations of macrophages (RFD7+, acid phosphatase-positive) in the fetal gastrointestinal and hepatic systems were HLA-DR+; the latter appear to include precursors of Kupffer cells in the developing liver.

Acid Phosphatase↗
PubMed1986

Immunophenotyping of T-lymphoblastic lymphoma/leukemia: correlation with normal T-cell maturation.

Twenty-nine cases of T-lymphoblastic lymphoma/leukemia were classified with conventional morphologic methods and the aid of monoclonal antibodies. All cases were investigated with a sensitive immunohistochemical method, using a panel of 22 monoclonal antibodies. In addition, normal thymus glands in the 22nd and 36th weeks of gestation were studied. Eight different groups of T-lymphoblastic lymphomas/leukemias could be distinguished, each of which showed a characteristic marker constellation. The results indicate that a complete detection of all thymic and prethymic lymphomas and leukemias is possible. By comparison with the phenotypic pattern of normal peripheral T-lymphocytes and their thymic precursors, the groups could be arranged in a sequence that resembles normal T-cell maturation, monoclonal antibodies.

Adolescent↗
PubMed1986

Analysis by sequential immunoprecipitations of the specificities of the monoclonal antibodies TU22,34,35,36,37,39,43,58 and YD1/63.HLK directed against human HLA class II antigens.

The monoclonal antibodies (MOABs) TU22, TU34, TU35, TU36, TU37, TU39, TU43, TU58 and YD1/63.HLK were used to identify subpopulations of class II antigens encoded by the human major histocompatibility complex. Since all MOABs reacted with B lymphocytes of HLA-DR1-8 homozygous as well as all heterozygous cells tested, they recognize monomorphic determinants, with the possible exception of TU58 and YD1/63.HLK which do not fix complement. As shown by radioactive binding assays and immunoprecipitations of labeled chains, 3 MOABs reacted strongly and 3 others weakly with isolated beta-chains, and the former also bound alpha-chains, albeit very weakly. Immunoprecipitations with the MOABs from 125I-labeled KR3598 cells (Dw5, DR5, MT2, MB3 homozygous, SB2, SB4) demonstrated that at least 4 different subpopulations of class II antigens were present in the lysate. Possibilities to reconcile these biochemical data with the reactivity of the MOABs with HLA mutant cell lines and with functional as well as tissue distribution studies are discussed.

Animals↗
PubMed1986

Absence of HLA class I and class II antigens as well as beta 2-microglobulin from normal and pathological human spermatozoa.

Human spermatozoa from 87 donors with normal or pathologic semen specimen were examined for the expression of HLA-class I and class II antigens as well as beta 2-microglobulin (beta 2m) using a panel of monoclonal antibodies in an indirect immunofluorescence test. The results make it very unlikely that HLA-class I and class II molecules as well as beta 2m are expressed on human sperm cells.

Antibodies, Monoclonal↗
PubMed1986

Gamma ray-induced mutants as a tool for the production and characterisation of monoclonal antibodies against HLA-alloantigens.

To simplify the screening procedure for murine monoclonal antibodies specific for polymorphic HLA determinants, spleen cells from a mouse immunized with the human cell line BJAB-B95.8.6 were fused with NS1 mouse myeloma cells, and hybridoma supernatants were screened for their reactivity on BJAB-B95.8.6 and two gamma ray-induced HLA-loss mutants of this line. The use of these HLA-loss mutants allowed the rapid identification of two new allospecific MOABs designated TU160 and TU161. Serological as well as biochemical studies revealed TU160 to be specific for HLA-A2, and TU161 for HLA-B13 molecules, respectively. Both MOABs were determined to be antibodies of the IgG class and were able to precipitate their antigens from lysates of radioactively labeled cells.

Animals↗
PubMed1985

5'-O-Palmitoyl- and 3',5'-O-dipalmitoyl-5-fluoro-2'-deoxyuridine--novel lipophilic analogues of 5'-fluoro-2'-deoxyuridine: synthesis, incorporation into liposomes and preliminary biological results.

5'-O-palmitoyl- and 3',5'-O-dipalmitoyl-5-fluoro-2'-deoxyuridine were prepared by the reaction of 5-fluoro-2'-deoxyuridine in dimethylacetamide with palmitic acid chloride. The incorporation of the synthesized prodrugs into liposomes composed of egg phosphatidylcholine/stearylamine/cholesterol/alpha-tocopherol at a molar ratio of 10:1:2:0.05 was nearly quantitative; homogeneous bilayer vesicles (75 nm diameter) were obtained. Preliminary tolerance studies revealed that the prodrug-liposome preparations are about 20-60 times more toxic than the parent drug. The prodrugs incorporated into liposomes were 10 to 30 times more active against murine colon 38 carcinoma compared to the free drug. In comparison to the administration of the prodrugs in peanut oil the liposomal preparations seem to exert improved effects and represent a valuable drug delivery system for parenteral applications.

Animals↗
PubMed1985

Refinement of HLA gene mapping with induced B-cell line mutants.

The lymphoma cell line BJAB.B95.8.6 was gamma-irradiated to induce mutations of major histocompatibility complex (MHC) encoded genes. Cloned "wild-type" cells were phenotyped HLA-A1, A2, B13, B35, Bw4, Bw6, Cw4, DR5, DRw52, DQw1, DQw3, DPw2, DPw4, GLO1 1, PGM3 2-1, and ME1 0 and possessed two apparently normal chromosome 6s prior to mutagenesis. Loss mutants were selected 5 days after 3 Gy gamma-irradiation employing three complement-fixing monoclonal antibodies specific for HLA-A2 (TU101) and Bw4 (TU48, TU109). Fifteen independently arising mutants were isolated and cloned. Typing with monospecific alloantisera and cell-mediated lympholysis revealed the presence of HLA-A1, B35, Bw6, Cw4, DR5, DRw52, DQw3, and DPw4 specificities on all mutant clones. HLA-A2, B13, and Bw4 were absent. Mutants differed in their expression of class II antigens. One group retained DQw1 and DPw2, another was DQw1-, DPw2+, and a third was DQw1-, DPw2-. Karyotyping of the "wild-type" line and selected mutant clones showed that the loss of HLA specificities correlated with deletions which map the HLA-A and -B loci directly to the distal part of the 6p21.33 region and the class II genes to the region 6p21.33 (proximal) to 6p21.31 (distal) on the short arm of chromosome 6.

Antibodies, Monoclonal↗
PubMed1985

Characterization of a monoclonal anti-Bw4 antibody (Tü109): evidence for similar epitopes on the Bw4 and Bw6 antigens.

The production and serologic, as well as immunochemical properties of a cytotoxic murine IgG monoclonal antibody (Tü109) that precipitates HLA-class I molecules, are described. In the microcytotoxicity assay Tü109 supernatant was demonstrated on a panel of 424 HLA-ABC, -DR, -DQ, -MT typed normal Caucasian blood donors to define an epitope on HLA-B locus molecules in great association with the supertypic specificity Bw4. Reactivity of supernatant showed MHC linked inheritance of the Tü109 determinant and discriminated the HLA-Bw4/Bw6 associated HLA-B locus split antigens. Weak or lack of binding on lymphocytes from some HLA-Bw4 heterozygous individuals, particularly typing for HLA-Bw44, appeared to be due to qualitative and/or quantitative variations of HLA-B locus molecules on the cell surface. With Tü109 ascites fluid, however, extra-reactivity on all HLA-Bw6+ cells was demonstrated. Preferential binding of supernatant to HLA-Bw4, but reactivity of ascites fluid with HLA-Bw6+ molecules in addition, was furthermore confirmed by IEF analysis of antigens immunoprecipitated with Tü109 from cell lysates. Thus the antibody may help to analyze the evolutionary relationship of the diallelic specificities Bw4 and Bw6.

Antibodies, Monoclonal↗
PubMed1985

Dissection of human allostimulatory determinants with cloned T cells: stimulation inhibition by monoclonal antibodies TU22, 34, 35, 36, 37, 39, 43, and 58 against distinct human MHC class II molecules.

Alloantigenic determinants causing secondary lymphoproliferative responses of primed T cells were investigated by blocking stimulation with monoclonal antibodies TU22, 34, 35, 36, 37, 39, 43, and 58 binding differentially to HLA-DR and SB or MB associated molecules. In particular, the use of cloned and functionally defined T cell responders greatly facilitated the assignment of stimulator-level inhibition caused by these antibodies. Thus, a novel way of functional "mapping" for stimulatory epitopes for sets of clones with restimulation specificities associated with HLA-D, SB, MB, or hitherto unidentified class II determinants is presented here. This considerably helps to elucidate the distinct immunoregulatory roles of the three major class II alloantigen systems thus far defined.

Antibodies, Monoclonal↗
PubMed1985

Specificity of monoclonal antibodies directed against human and murine class II histocompatibility antigens as analyzed by binding to HLA-deletion mutant cell lines.

The specificity of 70 monoclonal anti-Ia monoclonal antibodies (MoAbs) (18 mouse allo-induced and 52 rodent anti-human) was studied with a panel of 17 HLA-deletion mutants that were derived from a single parent line and vary in expression of Ia antigens due to deletion of different subregions of HLA. MoAb binding was analyzed both by ELISA and flow microfluorometry. Characterization of the MoAbs with respect to specificity for products of subregions of a DR1-DC1-SB2 haplotype revealed great complexity. Many antibodies were quite specific for DR-linked determinants (26 MoAbs), DC-linked determinants (5 MoAbs), or determinants indistinguishable from SB (4 MoAbs). However, many MoAbs bound to products of more than one subregion: DR + SB (+/- weak DC) (22 MoAbs); DR + DC (3 MoAbs); or DR + DC + SB (1 MoAb). Furthermore, a number of the MoAbs bound unequally to products of the two HLA haplotypes analyzed, particularly among those recognizing DC1-linked determinants and the murine alloinduced MoAbs. Finally, despite strong structural homologies of murine I-A to human DC and murine I-E to human DR, the intraspecies cross-reactions of MoAbs do not closely follow that pattern. These data: (1) illustrate the usefulness of HLA-deletion mutant cell lines for analysis of the specificity of MoAbs and for delineation of HLA subregions; (2) demonstrate the great diversity of MoAbs specific for class II molecules and the high frequency of MoAbs that bind to products of more than one Ia subregion, particularly DR and SB. In view of such complexity, many (perhaps most) MoAbs cannot be relied on to unambiguously identify products of a particular Ia subregion, without extensive characterization.

Animals↗
PubMed1985

Monosomy 6 in a human lymphoma line induced by selection with a monoclonal antibody.

The human Epstein Barr Virus-superinfected B lymphoma cell line BJAB-B95.8.6 was mutagenized by gamma irradiation, and HLA mutants were selected with the HLA-Bw6-specific monoclonal antibody SFR8-B6. One of the mutants obtained, BM19, had lost one of the chromosomes 6 present in the wild type cells. Electrophoretic analysis of phosphoglucomutase isozyme PGM3 and erythrocyte glyoxalase 1 from both cells supports this conclusion. The HLA antigens expressed on BM19 were HLA-A2, B13, Bw4, C-, DR2 (questionable), DRw52 (weak) and DQw1. This constitutes one of the haplotypes of the wild type cells, the other (lost from BM19 cells) being HLA-A1, B35, Bw6, Cw4, DR5, DRw52 (strong) and DQw3. Possibilities to employ BM19 cells for the analysis of the major histocompatibility complex and other chromosome 6-encoded genes as well as their products are discussed.

Antibodies, Monoclonal↗
PubMed1985

Divergent expression of HLA-DC/MB, -DR, and -SB region products on normal and pathological tissues as detected by monoclonal antibodies.

A group of eight monoclonal antibodies directed against different monomorphic determinants of HLA-class II molecules was used to investigate the distribution of HLA-DC/DS/MB, -DR and -SB-like antigens on normal and pathological lymphoid and nonlymphoid tissues of human adult and fetal donors. HLA-MB/DC/DS-like molecules, as defined by the antibody TU 22, showed the most limited distribution as they were detected on B-lymphocytes, monocyte/macrophage subpopulations and distinct interstitial cells of various organs. HLA-DR and -SB-like antigens characterized by the other anti-HLA-class II reagents (TU34, TU35, TU37, TU39, TU43, TU58) were also present on these cell types. However, selective expression of HLA-DR and/or -SB like molecules was demonstrated with these antibodies on certain vascular endothelia, as well as different B-cell lymphomas and distinct epithelial cells in adults. Exclusive reactivity of the antibody TU39 shown on endothelial cells of fetal liver and kidney suggested specific functions of HLA-SB antigens during ontogeny. Furthermore, HLA-DR and/or -SB like molecules but not TU22+ HLA-DC/MB antigens were found to be inducible on normally Ia-like antigen negative epithelial cells of various diseased organs. Implications of this differential tissue distribution of HLA-DC/MB/DS, -DR and -SB like products in relation to organ transplantation, regulation of immune responses and cell differentiation are discussed.

Adult↗
PubMed1985

Expression of HLA-A and -B antigens on differentiating U-937 cells.

Cells from the human immature monocytoid cell line U-937 were induced with 12-O-Tetradecanoyl-phorbol-13-acetate (TPA) to differentiate towards macrophage-like cells. The expression of HLA-antigens during differentiation was examined with a panel of monoclonal antibodies directed against monomorphic and polymorphic determinants. Class II antigens could be detected neither on uninduced nor on TPA-induced U-937 cells. While the expression of HLA-A3 did not change significantly during differentiation, the "supertypic" specificities HLA-Bw4 and Bw6 as well as the "private" specificity HLA-B18 could be detected only on a drastically decreased number of cells after 4 days of exposure to TPA. This may imply a selective loss of HLA-B molecules from the cell membrane and therefore a separate regulatory control of HLA-A and -B antigens.

Cell Differentiation↗